trunk/ipslv-temp/slv4.comp.c

/*
 *  SLV: Ascend Nonlinear Solver
 *  by Karl Michael Westerberg
 *  Created: 2/6/90
 *  Version: $Revision: $
 *  Version control file: $RCSfile: $
 *  Date last modified: $Date: $
 *  Last modified by: $Author: $
 *
 *  This file is part of the SLV solver.
 *
 *  Copyright (C) 1990 Karl Michael Westerberg
 *  Copyright (C) 1993 Joseph Zaher
 *  Copyright (C) 1994 Joseph Zaher, Benjamin Andrew Allan
 *
 *  The SLV solver is free software; you can redistribute
 *  it and/or modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version.
 *
 *  The SLV solver is distributed in hope that it will be
 *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with the program; if not, write to the Free Software Foundation,
 *  Inc., 675 Mass Ave, Cambridge, MA 02139 USA.  Check the file named
 *  COPYING.  COPYING is found in ../compiler.
 *
 */

#include <math.h>
#include <stdarg.h>
#include "utilities/ascConfig.h"
#include "utilities/ascSignal.h"
#include "utilities/ascMalloc.h"
#include "utilities/set.h"
#include "general/time.h"
#include "utilities/mem.h"
#include "utilities/ascPanic.h"
#include "general/list.h"
#include "compiler/fractions.h"
#include "compiler/dimen.h"
#include "compiler/functype.h"
#include "compiler/func.h"
#include "solver/mtx.h"
#include "solver/linsol.h"
#include "solver/linsolqr.h"
#include "solver/slv_types.h"
#include "solver/var.h"
#include "solver/rel.h"
#include "solver/discrete.h"
#include "solver/conditional.h"
#include "solver/logrel.h"
#include "solver/bnd.h"
#include "solver/calc.h"
#include "solver/relman.h"
#include "solver/slv_common.h"
#include "solver/slv_client.h"
#include "solver/slv4.h"
#include "solver/slv_stdcalls.h"

#if !defined(STATIC_QRSLV) && !defined(DYNAMIC_QRSLV)
int slv4_register(SlvFunctionsT *f)
{
  (void)f;  /* stop gcc whine about unused parameter */

  FPRINTF(stderr,"QRSlv not compiled in this ASCEND IV.\n");
  return 1;
}
#else /* either STATIC_QRSLV or DYNAMIC_QRSLV is defined */
#ifdef DYNAMIC_QRSLV
/* do dynamic loading stuff.   yeah, right */
#else /* following is used if STATIC_QRSLV is defined */

#define DEBUG FALSE
#define DEBUG_COMPLEMENTARY_VAR TRUE
#define SLV4(s) ((slv4_system_t)(s))
#define SERVER (sys->slv)
#define slv4_PA_SIZE 46 /* MUST INCREMENT WHEN ADDING PARAMETERS */
#define slv4_RA_SIZE 11

/* do not delete (or extend) this array definition.
*/
#define IEX(n) slv4_iaexpln[(n)]
#define slv4_IA_SIZE 16
static char *slv4_iaexpln[slv4_IA_SIZE] = {
"If lifds != 0 and showlessimportant is TRUE, show direct solve details",
"If savlin != 0, write out matrix data file at each iteration to SlvLinsol.dat",
"scale residuals by relation nominals for evaluating progress",
"Cutoff is the block size cutoff for MODEL-based reordering of partitions",
"Update jacobian every this many major iterations",
"Update row scalings every this many major iterations",
"Update column scalings every this many major iterations",
"Require misunderstood reduction somewhere in the stepping algorithm",
"Require residual >= some other number in the stepping algorithm",
"Check jacobian for poorly scaled columns and whine if found",
"Truncate whole step vector rather than componentwise at variable bound",
"Reorder option. 0 = MODEL based, 1 = MODEL based2, 2 = simple spk1",
"Use safe calculation routines",
"Update relation nominal scalings every this many major iterations",
"Max iterations for iterative scaling",
"scaleopt = 0: 2norm,= 1: relnom,= 2 2norm + iterative,= 3: relnom + iterative,= 4: iterative"
};

/* change  slv4_PA_SIZE above (MUST INCREMENT) WHEN ADDING PARAMETERS */
#define UPDATE_JACOBIAN_PTR (sys->parm_array[0])
#define UPDATE_JACOBIAN     ((*(int *)UPDATE_JACOBIAN_PTR))
#define UPDATE_WEIGHTS_PTR  (sys->parm_array[1])
#define UPDATE_WEIGHTS      ((*(int *)UPDATE_WEIGHTS_PTR))
#define UPDATE_NOMINALS_PTR (sys->parm_array[2])
#define UPDATE_NOMINALS     ((*(int *)UPDATE_NOMINALS_PTR))
#define REDUCE_PTR      (sys->parm_array[3])
#define REDUCE          ((*(int *)REDUCE_PTR))
#define EXACT_LINE_SEARCH_PTR   (sys->parm_array[4])
#define EXACT_LINE_SEARCH   ((*(int *)EXACT_LINE_SEARCH_PTR))
#define DUMPCNORM_PTR       (sys->parm_array[5])
#define DUMPCNORM       ((*(int *)DUMPCNORM_PTR))
#define TRUNCATE_PTR        (sys->parm_array[6])
#define TRUNCATE        ((*(int *)TRUNCATE_PTR))
#define SAFE_CALC_PTR       (sys->parm_array[7])
#define SAFE_CALC       ((*(int *)SAFE_CALC_PTR))
#define SCALEOPT_PTR        (sys->parm_array[8])
#define SCALEOPT        ((*(char **)SCALEOPT_PTR))
#define UPDATE_RELNOMS_PTR  (sys->parm_array[9])
#define UPDATE_RELNOMS      ((*(int *)UPDATE_RELNOMS_PTR))
#define ITSCALELIM_PTR      (sys->parm_array[10])
#define ITSCALELIM      ((*(int *)ITSCALELIM_PTR))
#define RELNOMSCALE_PTR     (sys->parm_array[11])
#define RELNOMSCALE     ((*(int *)RELNOMSCALE_PTR))
#define TOO_SMALL_PTR       (sys->parm_array[12])
#define TOO_SMALL       ((*(real64 *)TOO_SMALL_PTR))
#define CNLOW_PTR       (sys->parm_array[13])
#define CNLOW           ((*(real64 *)CNLOW_PTR))
#define CNHIGH_PTR      (sys->parm_array[14])
#define CNHIGH          ((*(real64 *)CNHIGH_PTR))
#define TOWARD_BOUNDS_PTR   (sys->parm_array[15])
#define TOWARD_BOUNDS       ((*(real64 *)TOWARD_BOUNDS_PTR))
#define POSITIVE_DEFINITE_PTR   (sys->parm_array[16])
#define POSITIVE_DEFINITE   ((*(real64 *)POSITIVE_DEFINITE_PTR))
#define DETZERO_PTR     (sys->parm_array[17])
#define DETZERO         ((*(real64 *)DETZERO_PTR))
#define STEPSIZEERR_MAX_PTR (sys->parm_array[18])
#define STEPSIZEERR_MAX     ((*(real64 *)STEPSIZEERR_MAX_PTR))
#define PARMRNG_MIN_PTR     (sys->parm_array[19])
#define PARMRNG_MIN     ((*(real64 *)PARMRNG_MIN_PTR))
#define MIN_COEF_PTR        (sys->parm_array[20])
#define MIN_COEF        ((*(real64 *)MIN_COEF_PTR))
#define MAX_COEF_PTR        (sys->parm_array[21])
#define MAX_COEF        ((*(real64 *)MAX_COEF_PTR))
#define ITSCALETOL_PTR      (sys->parm_array[22])
#define ITSCALETOL      ((*(real64 *)ITSCALETOL_PTR))
#define IGNORE_BOUNDS_PTR   (sys->parm_array[23])
#define IGNORE_BOUNDS       ((*(int32 *)IGNORE_BOUNDS_PTR))
#define SHOW_MORE_IMPT_PTR  (sys->parm_array[24])
#define SHOW_MORE_IMPT      ((*(int32 *)SHOW_MORE_IMPT_PTR))
#define RHO_PTR         (sys->parm_array[25])
#define RHO         ((*(real64 *)RHO_PTR))
#define PARTITION_PTR       (sys->parm_array[26])
#define PARTITION       ((*(int32 *)PARTITION_PTR))
#define SHOW_LESS_IMPT_PTR  (sys->parm_array[27])
#define SHOW_LESS_IMPT      ((*(int32 *)SHOW_LESS_IMPT_PTR))
#define AUTO_RESOLVE_PTR    (sys->parm_array[28])
#define AUTO_RESOLVE        ((*(int32 *)AUTO_RESOLVE_PTR))
#define TIME_LIMIT_PTR      (sys->parm_array[29])
#define TIME_LIMIT      ((*(int32 *)TIME_LIMIT_PTR))
#define ITER_LIMIT_PTR      (sys->parm_array[30])
#define ITER_LIMIT      ((*(int32 *)ITER_LIMIT_PTR))
#define STAT_TOL_PTR        (sys->parm_array[31])
#define STAT_TOL        ((*(real64 *)STAT_TOL_PTR))
#define TERM_TOL_PTR        (sys->parm_array[32])
#define TERM_TOL        ((*(real64 *)TERM_TOL_PTR))
#define SING_TOL_PTR        (sys->parm_array[33])
#define SING_TOL        ((*(real64 *)SING_TOL_PTR))
#define PIVOT_TOL_PTR       (sys->parm_array[34])
#define PIVOT_TOL       ((*(real64 *)PIVOT_TOL_PTR))
#define FEAS_TOL_PTR        (sys->parm_array[35])
#define FEAS_TOL        ((*(real64 *)FEAS_TOL_PTR))
#define LIFDS_PTR       (sys->parm_array[36])
#define LIFDS           ((*(int32 *)LIFDS_PTR))
#define SAVLIN_PTR      (sys->parm_array[37])
#define SAVLIN          ((*(int32 *)SAVLIN_PTR))
#define REORDER_OPTION_PTR  (sys->parm_array[38])
#define REORDER_OPTION      ((*(char **)REORDER_OPTION_PTR))
#define CUTOFF_PTR      (sys->parm_array[39])
#define CUTOFF          ((*(int32 *)CUTOFF_PTR))
#define FACTOR_OPTION_PTR   (sys->parm_array[40])
#define FACTOR_OPTION       ((*(char **)FACTOR_OPTION_PTR))
#define CONVOPT_PTR     (sys->parm_array[41])
#define CONVOPT         ((*(char **)CONVOPT_PTR))
#define LINTIME_PTR     (sys->parm_array[42])
#define LINTIME         ((*(int *)LINTIME_PTR))
#define TRUNCATE_COMP_PTR   (sys->parm_array[43])
#define TRUNCATE_COMP       ((*(int *)TRUNCATE_COMP_PTR))
#define TRUNCATE_ALL_PTR    (sys->parm_array[44])
#define TRUNCATE_ALL        ((*(int *)TRUNCATE_ALL_PTR))
#define TOWARD_COMP_BOUNDS_PTR  (sys->parm_array[45])
#define TOWARD_COMP_BOUNDS  ((*(real64 *)TOWARD_COMP_BOUNDS_PTR))
/* change  slv4_PA_SIZE above (MUST INCREMENT) WHEN ADDING PARAMETERS */


#define REX(n) slv4_raexpln[(n)]
static
char *slv4_raexpln[slv4_RA_SIZE] = {
"Var nominal to use if user specifies 0.0",
"Smallest column norm we won't complain about if checking",
"Largest column norm we won't complain about if checking",
"If bound is in the way, we go this fraction toward it",
"Hessian fudge number when optimizing",
"Minimum 2x2 determinant of newton/gradient we consider non-parallel",
"Step size must be determined this precisely, or prngmin happy",
"Parameter range must be this narrow to exit inner loop if step size unhappy",
"'Largest' drop in maxstep allowed",
"'Smallest' drop in maxstep allowed",
"scale termination ratio for iterative method"};

struct update_data {
  int                    jacobian;   /* Countdown on jacobian updating */
  int                    weights;    /* Countdown on weights updating */
  int                    nominals;   /* Countdown on nominals updating */
  int                    relnoms;    /* Countdown on relnom updating */
  int                    iterative;  /* Countdown on iterative scale update */
};


struct jacobian_data {
  linsolqr_system_t      sys;          /* Linear system */
  mtx_matrix_t           mtx;          /* Transpose gradient of residuals */
  real64                 *rhs;         /* RHS from linear system */
  dof_t                  *dofdata;     /* dof data pointer from server */
  mtx_region_t           reg;          /* Current block region */
  int32                  rank;         /* Numerical rank of the jacobian */
  enum factor_method     fm;           /* Linear factorization method */
  boolean                accurate;     /* ? Recalculate matrix */
  boolean                singular;     /* ? Can matrix be inverted */
  boolean                old_partition;/* old value of partition flag */
};

struct slv4_system_structure {

  /*
   *  Problem definition
   */
  slv_system_t              slv;   /* slv_system_t back-link */
  struct rel_relation         *obj;    /* Objective function: NULL = none */
  struct var_variable         **vlist; /* Variable list (NULL terminated) */
  struct rel_relation         **rlist; /* Relation list (NULL terminated) */

  /*
   *  Solver information
   */
  int                    integrity;    /* ? Has the system been created */
  int32                  presolved;    /* ? Has the system been presolved */
  slv_parameters_t       p;            /* Parameters */
  slv_status_t           s;            /* Status (as of iteration end) */
  struct update_data     update;       /* Jacobian frequency counters */
  int32                  cap;          /* Order of matrix/vectors */
  int32                  rank;         /* Symbolic rank of problem */
  int32                  vused;        /* Free and incident variables */
  int32                  vtot;         /* length of varlist */
  int32                  rused;        /* Included relations */
  int32                  rtot;         /* length of rellist */
  double                 clock;        /* CPU time */
  void *parm_array[slv4_PA_SIZE];      /* array of pointers to param values */
  struct slv_parameter pa[slv4_PA_SIZE];/* &pa[0] => sys->p.parms */

  /*
   *  Calculated data (scaled)
   */
  struct jacobian_data   J;            /* linearized system */
  struct vector_data     nominals;     /* Variable nominals */
  struct vector_data     weights;      /* Relation weights */
  struct vector_data     relnoms;      /* Relation nominals */
  struct vector_data     variables;    /* Variable values */
  struct vector_data     residuals;    /* Relation residuals */
  struct vector_data     gamma;        /* Feasibility steepest descent */
  struct vector_data     Jgamma;       /* Product of J and gamma */
  struct vector_data     newton;       /* Dependent variables */
  struct vector_data     varstep1;     /* 1st order in variables */
  struct vector_data     varstep2;     /* 2nd order in variables */
  struct vector_data     varstep;      /* Step in variables */

  real64                 objective;    /* Objective function evaluation */
  real64                 phi;          /* Unconstrained minimizer */
  real64                 maxstep;      /* Maximum step size allowed */
  real64                 progress;     /* Steepest directional derivative */
};


/*
 *  Integrity checks
 *  ----------------
 *     check_system(sys)
 */

#define OK        ((int)813029392)
#define DESTROYED ((int)103289182)
static int check_system(slv4_system_t sys)
/*
 *  Checks sys for NULL and for integrity.
 */
{
  if( sys == NULL ) {
    FPRINTF(stderr,"ERROR:  (slv4) check_system\n");
    FPRINTF(stderr,"        NULL system handle.\n");
    return 1;
  }

  switch( sys->integrity ) {
  case OK:
    return 0;
  case DESTROYED:
    FPRINTF(stderr,"ERROR:  (slv4) check_system\n");
    FPRINTF(stderr,"        System was recently destroyed.\n");
    return 1;
  default:
    FPRINTF(stderr,"ERROR:  (slv4) check_system\n");
    FPRINTF(stderr,"        System reused or never allocated.\n");
    return 1;
  }
}

/*
 *  General input/output routines
 *  -----------------------------
 *     print_var_name(out,sys,var)
 *     print_rel_name(out,sys,rel)
 */

#define print_var_name(a,b,c) slv_print_var_name((a),(b)->slv,(c))
#define print_rel_name(a,b,c) slv_print_rel_name((a),(b)->slv,(c))

/*
 *  Debug output routines
 *  ---------------------
 *     debug_delimiter(fp)
 *     debug_out_vector(fp,vec)
 *     debug_out_var_values(fp,sys)
 *     debug_out_rel_residuals(fp,sys)
 *     debug_out_jacobian(fp,sys)
 *     debug_write_array(fp,real64 *,length)
 *     debug_out_parameters(fp)
 */

/*
 *  Outputs a hyphenated line.
 */
static void debug_delimiter( FILE *fp)
{
  int i;
  for( i=0; i<60; i++ ) PUTC('-',fp);
  PUTC('\n',fp);
}

#if DEBUG
/*
 *  Outputs a vector.
 */
static void debug_out_vector( FILE *fp, slv4_system_t sys,
                              struct vector_data *vec)
{
  int32 ndx;
  FPRINTF(fp,"Norm = %g, Accurate = %s, Vector range = %d to %d\n",
    calc_sqrt_D0(vec->norm2), vec->accurate?"TRUE":"FALSE",
    vec->rng->low,vec->rng->high);
  FPRINTF(fp,"Vector --> ");
  for( ndx=vec->rng->low ; ndx<=vec->rng->high ; ++ndx )
    FPRINTF(fp, "%g ", vec->vec[ndx]);
  PUTC('\n',fp);
}

/*
 *  Outputs all variable values in current block.
 */
static void debug_out_var_values( FILE *fp, slv4_system_t sys)
{
  int32 col;
  struct var_variable *var;

  FPRINTF(fp,"Var values --> \n");
  for( col = sys->J.reg.col.low; col <= sys->J.reg.col.high ; col++ ) {
    var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
    print_var_name(fp,sys,var);
    FPRINTF(fp, "\nI    Lb  Value   Ub  Scale   Col INom\n");
    FPRINTF(fp,"%d\t%.4g\t%.4g\t%.4g\t%.4g\t%d\t%.4g\n",
      var_sindex(var),var_lower_bound(var),var_value(var),
      var_upper_bound(var),var_nominal(var),
      col,sys->nominals.vec[col]);
  }
}

/*
 *  Outputs all relation residuals in current block.
 */
static void debug_out_rel_residuals( FILE *fp, slv4_system_t sys)
{
  int32 row;

  FPRINTF(fp,"Rel residuals --> \n");
  for( row = sys->J.reg.row.low; row <= sys->J.reg.row.high ; row++ ) {
    struct rel_relation *rel;
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
    FPRINTF(fp,"  %g : ",rel_residual(rel));
    print_rel_name(fp,sys,rel);
    PUTC('\n',fp);
  }
  PUTC('\n',fp);
}

/*
 *  Outputs permutation and values of the nonzero elements in the
 *  the jacobian matrix.
 */
static void debug_out_jacobian( FILE *fp, slv4_system_t sys)
{
  mtx_coord_t nz;
  real64 value;

  nz.row = sys->J.reg.row.low;
  for( ; nz.row <= sys->J.reg.row.high; ++(nz.row) ) {
    FPRINTF(fp,"   Row %d (rel %d)\n", nz.row,
      mtx_row_to_org(sys->J.mtx,nz.row));
    nz.col = mtx_FIRST;
    while( value = mtx_next_in_row(sys->J.mtx,&nz,&(sys->J.reg.col)),
           nz.col != mtx_LAST ) {
      FPRINTF(fp,"      Col %d (var %d) has value %g\n", nz.col,
        mtx_col_to_org(sys->J.mtx,nz.col), value);
    }
  }
}

#endif

static void debug_write_array(FILE *fp,real64 *vec, int32 length)
{
  int32 i;
  for (i=0; i< length;i++)
    FPRINTF(fp,"%.20g\n",vec[i]);
}

static char savlinfilename[]="SlvLinsol.dat.\0";
static char savlinfilebase[]="SlvLinsol.dat.\0";
static int savlinnum=0;

/* The number to postfix to savlinfilebase. increases with file accesses. */

/*
 *  Array/vector operations
 *  ----------------------------
 *     destroy_array(p)
 *     create_array(len,type)
 *     zero_vector(vec)
 *     copy_vector(vec1,vec2)
 *     prod = inner_product(vec1,vec2)
 *     norm2 = square_norm(vec)
 *     matrix_product(mtx,vec,prod,scale,transpose)
 */

#define destroy_array(p)  \
   if( (p) != NULL ) ascfree((p))
#define create_array(len,type)  \
   ((len) > 0 ? (type *)ascmalloc((len)*sizeof(type)) : NULL)
#define create_zero_array(len,type)  \
   ((len) > 0 ? (type *)asccalloc((len),sizeof(type)) : NULL)

#define zero_vector(v) slv_zero_vector(v)
#define copy_vector(v,t) slv_copy_vector((v),(t))
#define inner_product(v,u) slv_inner_product((v),(u))
#define square_norm(v)  slv_square_norm(v)
#define matrix_product(m,v,p,s,t) slv_matrix_product((m),(v),(p),(s),(t))

/*
 *  Calculation routines
 *  --------------------
 *     ok = calc_objective(sys)
 *     ok = calc_boundaries(sys)
 *     ok = calc_residuals(sys)
 *     ok = calc_J(sys)
 *     calc_nominals(sys)
 *     calc_weights(sys)
 *     scale_J(sys)
 *     scale_variables(sys)
 *     scale_residuals(sys)
 *     calc_pivots(sys)
 *     calc_rhs(sys)
 *     calc_newton(sys)
 *     calc_gamma(sys)
 *     calc_Jgamma(sys)
 *     calc_varstep1(sys)
 *     calc_varstep2(sys)
 *     calc_varstep(sys)
 *     calc_phi(sys)
 */

/*
 *  Evaluate the objective function.
 */
static boolean calc_objective( slv4_system_t sys)
{
  calc_ok = TRUE;
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  sys->objective = (sys->obj ? relman_eval(sys->obj,&calc_ok,SAFE_CALC) : 0.0);
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  return calc_ok;
}

/*
 *  Evaluate all objectives.
 */
static boolean calc_objectives( slv4_system_t sys)
{
  int32 len,i;
  static rel_filter_t rfilter;
  struct rel_relation **rlist=NULL;
  rfilter.matchbits = (REL_INCLUDED);
  rfilter.matchvalue =(REL_INCLUDED);
  rlist = slv_get_solvers_obj_list(SERVER);
  len = slv_get_num_solvers_objs(SERVER);
  calc_ok = TRUE;
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  for (i = 0; i < len; i++) {
    if (rel_apply_filter(rlist[i],&rfilter)) {
      relman_eval(rlist[i],&calc_ok,SAFE_CALC);
#if DEBUG
      if (calc_ok == FALSE) {
    FPRINTF(stderr,"error in calc_objectives\n");
    calc_ok = TRUE;
      }
#endif
    }
  }
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  return calc_ok;
}


/*
 *  Calculates all of the residuals of included inequalities.
 *  Returns true iff (calculations preceded without error and
 *  all inequalities are satisfied.)
 */
static boolean calc_inequalities( slv4_system_t sys)
{
  struct rel_relation **rp;
  boolean satisfied=TRUE;
  static rel_filter_t rfilter;
  rfilter.matchbits = (REL_INCLUDED | REL_EQUALITY | REL_ACTIVE);
  rfilter.matchvalue = (REL_INCLUDED | REL_ACTIVE);

  calc_ok = TRUE;
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  for (rp=sys->rlist;*rp != NULL; rp++) {
    if (rel_apply_filter(*rp,&rfilter)) {
      relman_eval(*rp,&calc_ok,SAFE_CALC);
      satisfied= satisfied &&
      relman_calc_satisfied(*rp,FEAS_TOL);
    }
  }
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  return (calc_ok && satisfied);
}

/*
 *  Calculates all of the residuals in the current block and computes
 *  the residual norm for block status.  Returns true iff calculations
 *  preceded without error.
 */
static boolean calc_residuals( slv4_system_t sys)
{
  int32 row;
  struct rel_relation *rel;
  double time0;

  if( sys->residuals.accurate ) return TRUE;

  calc_ok = TRUE;
  row = sys->residuals.rng->low;
  time0=tm_cpu_time();
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  for( ; row <= sys->residuals.rng->high; row++ ) {
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
#if DEBUG
    if (!rel) {
      int r;
      r=mtx_row_to_org(sys->J.mtx,row);
      FPRINTF(stderr,"NULL relation found !!\n");
      FPRINTF(stderr,"at row %d rel %d in calc_residuals\n",(int)row,r);
      FFLUSH(stderr);
    }
#endif
    sys->residuals.vec[row] = relman_eval(rel,&calc_ok,SAFE_CALC);

    if (strcmp(CONVOPT,"ABSOLUTE") == 0) {
      relman_calc_satisfied(rel,FEAS_TOL);
    } else if (strcmp(CONVOPT,"RELNOM_SCALE") == 0) {
      relman_calc_satisfied_scaled(rel,FEAS_TOL);
    }
  }
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  sys->s.block.functime += (tm_cpu_time() -time0);
  sys->s.block.funcs++;
  square_norm( &(sys->residuals) );
  sys->s.block.residual = calc_sqrt_D0(sys->residuals.norm2);
  return(calc_ok);
}

/*
 *  Calculates the current block of the jacobian.
 *  It is initially unscaled.
 */
static boolean calc_J( slv4_system_t sys)
{
  int32 row;
  var_filter_t vfilter;
  double time0;
  real64 resid;

  if( sys->J.accurate )
    return TRUE;

  calc_ok = TRUE;
  vfilter.matchbits = (VAR_INBLOCK | VAR_ACTIVE);
  vfilter.matchvalue = (VAR_INBLOCK | VAR_ACTIVE);
  time0=tm_cpu_time();
  mtx_clear_region(sys->J.mtx,&(sys->J.reg));
  for( row = sys->J.reg.row.low; row <= sys->J.reg.row.high; row++ ) {
    struct rel_relation *rel;
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
    relman_diffs(rel,&vfilter,sys->J.mtx,&resid,SAFE_CALC);
  }
  sys->s.block.jactime += (tm_cpu_time() - time0);
  sys->s.block.jacs++;

  if( --(sys->update.nominals) <= 0 ) sys->nominals.accurate = FALSE;
  if( --(sys->update.weights) <= 0 ) sys->weights.accurate = FALSE;

  linsolqr_matrix_was_changed(sys->J.sys);
  return(calc_ok);
}

/*
 *  Retrieves the nominal values of all of the block variables,
 *  insuring that they are all strictly positive.
 */
static void calc_nominals( slv4_system_t sys)
{
  int32 col;
  FILE *fp = MIF(sys);
  if( sys->nominals.accurate ) return;
  fp = MIF(sys);
  col = sys->nominals.rng->low;
  if(strcmp(SCALEOPT,"NONE") == 0 ||
     strcmp(SCALEOPT,"ITERATIVE") == 0){
    for( ; col <= sys->nominals.rng->high; col++ ) {
      sys->nominals.vec[col] = 1;
    }
  } else {
    for( ; col <= sys->nominals.rng->high; col++ ) {
      struct var_variable *var;
      real64 n;
      var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
      n = var_nominal(var);
      if( n <= 0.0 ) {
    if( n == 0.0 ) {
      n = TOO_SMALL;
      FPRINTF(fp,"ERROR:  (slv4) calc_nominals\n");
      FPRINTF(fp,"        Variable ");
      print_var_name(fp,sys,var);
      FPRINTF(fp,"        \nhas nominal value of zero.\n");
      FPRINTF(fp,"        Resetting to %g.\n",n);
      var_set_nominal(var,n);
    } else {
      n =  -n;
      FPRINTF(fp,"ERROR:  (slv4) calc_nominals\n");
      FPRINTF(fp,"        Variable ");
      print_var_name(fp,sys,var);
      FPRINTF(fp,"        \nhas negative nominal value.\n");
      FPRINTF(fp,"        Resetting to %g.\n",n);
      var_set_nominal(var,n);
    }
      }
#if DEBUG
      FPRINTF(fp,"Column %d is");
      print_var_name(fp,sys,var);
      FPRINTF(fp,"\nScaling of column %d is %g\n",col,n);
#endif
      sys->nominals.vec[col] = n;
    }
  }
  square_norm( &(sys->nominals) );
  sys->update.nominals = UPDATE_NOMINALS;
  sys->nominals.accurate = TRUE;
}

/*
 *  Calculates the weights of all of the block relations
 *  to scale the rows of the Jacobian.
 */
static void calc_weights( slv4_system_t sys)
{
  mtx_coord_t nz;
  real64 sum;

  if( sys->weights.accurate )
    return;

  nz.row = sys->weights.rng->low;
  if(strcmp(SCALEOPT,"NONE") == 0 ||
     strcmp(SCALEOPT,"ITERATIVE") == 0) {
    for( ; nz.row <= sys->weights.rng->high; (nz.row)++ ) {
      sys->weights.vec[nz.row] = 1;
    }
  } else if (strcmp(SCALEOPT,"ROW_2NORM") == 0 ||
         strcmp(SCALEOPT,"2NORM+ITERATIVE") == 0) {
    for( ; nz.row <= sys->weights.rng->high; (nz.row)++ ) {
      sum=mtx_sum_sqrs_in_row(sys->J.mtx,nz.row,&(sys->J.reg.col));
      sys->weights.vec[nz.row] = (sum>0.0) ? 1.0/calc_sqrt_D0(sum) : 1.0;
    }
  } else if (strcmp(SCALEOPT,"RELNOM") == 0 ||
         strcmp(SCALEOPT,"RELNOM+ITERATIVE") == 0) {
    for( ; nz.row <= sys->weights.rng->high; (nz.row)++ ) {
      sys->weights.vec[nz.row] =
    1.0/rel_nominal(sys->rlist[mtx_row_to_org(sys->J.mtx,nz.row)]);
    }
  }
  square_norm( &(sys->weights) );
  sys->update.weights = UPDATE_WEIGHTS;
  sys->residuals.accurate = FALSE;
  sys->weights.accurate = TRUE;
}

/*
 *  Scales the jacobian.
 */
static void scale_J( slv4_system_t sys)
{
  int32 row;
  int32 col;

  if( sys->J.accurate ) return;

  calc_nominals(sys);
  for( col=sys->J.reg.col.low; col <= sys->J.reg.col.high; col++ )
    mtx_mult_col(sys->J.mtx,col,sys->nominals.vec[col],&(sys->J.reg.row));

  calc_weights(sys);
  for( row=sys->J.reg.row.low; row <= sys->J.reg.row.high; row++ )
     mtx_mult_row(sys->J.mtx,row,sys->weights.vec[row],&(sys->J.reg.col));
}

static void jacobian_scaled(slv4_system_t sys)
{
  int32 col;
  if (DUMPCNORM) {
    for( col=sys->J.reg.col.low; col <= sys->J.reg.col.high; col++ ) {
      real64 cnorm;
      cnorm =
        calc_sqrt_D0(mtx_sum_sqrs_in_col(sys->J.mtx,col,&(sys->J.reg.row)));
      if (cnorm >CNHIGH || cnorm <CNLOW) {
        FPRINTF(stderr,"[col %d org %d] %g\n", col,
          mtx_col_to_org(sys->J.mtx,col), cnorm);
      }
    }
  }

  sys->update.jacobian = UPDATE_JACOBIAN;
  sys->J.accurate = TRUE;
  sys->J.singular = FALSE;  /* yet to be determined */
#if DEBUG
  FPRINTF(LIF(sys),"\nJacobian: \n");
  debug_out_jacobian(LIF(sys),sys);
#endif
}

static void scale_variables( slv4_system_t sys)
{
  int32 col;

  if( sys->variables.accurate ) return;

  col = sys->variables.rng->low;
  for( ; col <= sys->variables.rng->high; col++ ) {
    struct var_variable *var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
    sys->variables.vec[col] = var_value(var)/sys->nominals.vec[col];
  }
  square_norm( &(sys->variables) );
  sys->variables.accurate = TRUE;
#if DEBUG
  FPRINTF(LIF(sys),"Variables:  ");
  debug_out_vector(LIF(sys),sys,&(sys->variables));
#endif
}

/*
 *  Scales the previously calculated residuals.
 */
static void scale_residuals( slv4_system_t sys)
{
  int32 row;

  if( sys->residuals.accurate ) return;

  row = sys->residuals.rng->low;
  for( ; row <= sys->residuals.rng->high; row++ ) {
    struct rel_relation *rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
     sys->residuals.vec[row] = rel_residual(rel)*sys->weights.vec[row];
  }
  square_norm( &(sys->residuals) );
  sys->residuals.accurate = TRUE;
#if DEBUG
  FPRINTF(LIF(sys),"Residuals:  ");
  debug_out_vector(LIF(sys),sys,&(sys->residuals));
#endif
}

/*
 * Calculates relnoms for all relations in sys
 * using variable nominals.
 */
static void calc_relnoms(slv4_system_t sys)
{
  int32 row, col;
  struct var_variable *var;
  struct rel_relation *rel;
  real64 *var_list;
  var_list = create_array(sys->cap,real64);
  col = 0;
  var = sys->vlist[col];
  /* store current variable values and
     set variable value to nominal value */
  while(var != NULL){
    var_list[col] = var_value(var);
    var_set_value(var, var_nominal(var));
    col++;
    var = sys->vlist[col];
  }
  row = 0;
  rel = sys->rlist[row];
  /* calculate relation nominal */
  while(rel != NULL){
    relman_scale(rel);
    row++;
    rel = sys->rlist[row];
  }
  col = 0;
  var = sys->vlist[col];
  /* restore variable values */
  while(var != NULL){
    var_set_value(var, var_list[col]);
    col++;
    var = sys->vlist[col];
  }
  destroy_array(var_list);
}

/*
 *  Returns the maximum ratio of magnitudes of any two nonzero
 *  elements in the same column of mtx.  Only considers elements
 *  in region reg.
 */
static real64 col_max_ratio(mtx_matrix_t *mtx, mtx_region_t *reg)
{
  real64 ratio;
  real64 max_ratio;
  real64 num, denom, dummy;
  mtx_coord_t coord;
  max_ratio = 0;
  for(coord.col = reg->col.low;
    coord.col <= reg->col.high; coord.col++) {
    ratio = 0;
    num = mtx_col_max(*mtx,&(coord),&(reg->row),&(dummy));
    denom = mtx_col_min(*mtx,&(coord),&(reg->row),&(dummy),1e-7);
    if(denom >0){
      ratio = num/denom;
    }
    if(ratio > max_ratio){
      max_ratio = ratio;
    }
  }
  if(max_ratio == 0){
    max_ratio = 1;
  }
  return max_ratio;
}


/*
 *  Returns the maximum ratio of magnitudes of any two nonzero
 *  elements in the same row of mtx.  Only considers elements
 *  in region reg.
 */
static real64 row_max_ratio(mtx_matrix_t *mtx,
                mtx_region_t *reg)
{
  real64 ratio;
  real64 max_ratio;
  real64 num, denom, dummy;
  mtx_coord_t coord;
  max_ratio = 0;
  for(coord.row = reg->row.low;
    coord.row <= reg->row.high; coord.row++) {
    ratio = 0;
    num = mtx_row_max(*mtx,&(coord),&(reg->col),&(dummy));
    denom = mtx_row_min(*mtx,&(coord),&(reg->col),&(dummy),1e-7);
    if(denom >0){
      ratio = num/denom;
    }
    if(ratio > 10000000){
/*      FPRINTF(stderr,"HELPME\n");*/
    }
    if(ratio > max_ratio){
      max_ratio = ratio;
    }
  }
  if(max_ratio == 0){
    max_ratio = 1;
  }
  return max_ratio;
}

/*
 *  Calculates scaling factor suggested by Fourer.
 *  For option = 0, returns scaling factor for
 *  row number loc.
 *  For option = 1, returns scaling factor for
 *  col number loc.
 */
static real64 calc_fourer_scale(mtx_matrix_t mtx,
                  mtx_region_t reg,
                  int32 loc,
                  int32 option)
{
  mtx_coord_t coord;
  real64 min, max, dummy;
  real64 scale;
  if(option == 0){
    if((loc < reg.row.low) || (loc > reg.row.high)){
      return 1;
    }
    coord.row = loc;
    min = mtx_row_min(mtx,&(coord),&(reg.col),&(dummy),1e-7);
    max = mtx_row_max(mtx,&(coord),&(reg.col),&(dummy));
    scale = min*max;
    if(scale > 0){
      scale = sqrt(scale);
    } else {
      scale = 1;
    }
    return scale;
  } else {
    if(loc < reg.col.low || loc > reg.col.high){
      return 1;
    }
    coord.col = loc;
    min = mtx_col_min(mtx,&(coord),&(reg.row),&(dummy),1e-7);
    max = mtx_col_max(mtx,&(coord),&(reg.row),&(dummy));
    scale = min*max;
    if(scale > 0){
      scale = sqrt(scale);
    } else {
      scale = 1;
    }
    return scale;
  }
}

/*
 *  This funcion is an implementation of the scaling
 *  routine by Fourer on p304 of Mathematical Programing
 *  vol 23, (1982).
 *  This function will scale the Jacobian and store the scaling
 *  factors in sys->nominals and sys->weights.
 *  If the Jacobian has been previously scaled
 *  by another method (during this iteration) then these vectors
 *  should contain the scale factors used in that scaling.
 */
static void scale_J_iterative(slv4_system_t sys)
{
  real64 rho_col_old, rho_col_new;
  real64 rho_row_old, rho_row_new;
  int32 k;
  int32 done;
  int32 row, col;
  real64 *colvec = sys->nominals.vec;
  real64 *rowvec = sys->weights.vec;
  real64 rowscale, colscale;
  rho_col_old = col_max_ratio(&(sys->J.mtx),&(sys->J.reg));
  rho_row_old = row_max_ratio(&(sys->J.mtx),&(sys->J.reg));
  k = 0;
  done = 0;
  while(done == 0){
    k++;
    for(row = sys->J.reg.row.low;
    row <= sys->J.reg.row.high; row++){
      rowscale = 1/calc_fourer_scale(sys->J.mtx,sys->J.reg,row,0);
      mtx_mult_row(sys->J.mtx,row,rowscale,&(sys->J.reg.col));
      rowvec[row] *= rowscale;
    }
    for(col = sys->J.reg.col.low;
    col <= sys->J.reg.col.high; col++){
      colscale = 1/calc_fourer_scale(sys->J.mtx,sys->J.reg,col,1);
      mtx_mult_col(sys->J.mtx,col,colscale,&(sys->J.reg.row));
      colvec[col] *= colscale;
    }
    rho_col_new = col_max_ratio(&(sys->J.mtx),&(sys->J.reg));
    rho_row_new = row_max_ratio(&(sys->J.mtx),&(sys->J.reg));
    if((rho_col_new >= ITSCALETOL*rho_col_old &&
    rho_row_new >= ITSCALETOL*rho_row_old)
       || k >= ITSCALELIM){
      done = 1;
    } else {
      rho_row_old = rho_row_new;
      rho_col_old = rho_col_new;
    }
  }
  square_norm( &(sys->nominals) );
  sys->update.nominals = UPDATE_NOMINALS;
  sys->nominals.accurate = TRUE;

  square_norm( &(sys->weights) );
  sys->update.weights = UPDATE_WEIGHTS;
  sys->residuals.accurate = FALSE;
  sys->weights.accurate = TRUE;
}

/*
 * Scale system dependent on interface parameters
 */
static void scale_system( slv4_system_t sys )
{
  if(strcmp(SCALEOPT,"NONE") == 0){
    if(sys->J.accurate == FALSE){
      calc_nominals(sys);
      calc_weights(sys);
      jacobian_scaled(sys);
    }
    scale_variables(sys);
    scale_residuals(sys);
    return;
  }
  if(strcmp(SCALEOPT,"ROW_2NORM") == 0 ||
     strcmp(SCALEOPT,"RELNOM") == 0){
    if(sys->J.accurate == FALSE){
      scale_J(sys);
      jacobian_scaled(sys);
    }
    scale_variables(sys);
    scale_residuals(sys);
    return;
  }
  if(strcmp(SCALEOPT,"2NORM+ITERATIVE") == 0 ||
     strcmp(SCALEOPT,"RELNOM+ITERATIVE") == 0){
    if(sys->J.accurate == FALSE){
      --sys->update.iterative;
      if(sys->update.iterative <= 0) {
    scale_J(sys);
    scale_J_iterative(sys);
    sys->update.iterative =
      UPDATE_WEIGHTS < UPDATE_NOMINALS ? UPDATE_WEIGHTS : UPDATE_NOMINALS;
      } else {
    sys->weights.accurate = TRUE;
    sys->nominals.accurate = TRUE;
    scale_J(sys); /* will use current scaling vectors */
      }
      jacobian_scaled(sys);
    }
    scale_variables(sys);
    scale_residuals(sys);
    return;
  }
  if(strcmp(SCALEOPT,"ITERATIVE") == 0){
    if(sys->J.accurate == FALSE){
      --sys->update.iterative;
      if(sys->update.iterative <= 0) {
    calc_nominals(sys);
    calc_weights(sys);
    scale_J_iterative(sys);
    sys->update.iterative =
      UPDATE_WEIGHTS < UPDATE_NOMINALS ? UPDATE_WEIGHTS : UPDATE_NOMINALS;
      } else {
    sys->weights.accurate = TRUE;
    sys->nominals.accurate = TRUE;
    scale_J(sys); /* will use current scaling vectors */
      }
      jacobian_scaled(sys);
    }
    scale_variables(sys);
    scale_residuals(sys);
  }
  return;
}


/*
 *  Obtain the equations and variables which
 *  are able to be pivoted.
 *  return value is the row rank deficiency, which we hope is 0.
 */
static int calc_pivots(slv4_system_t sys)
{
  int row_rank_defect=0, oldtiming;
  linsolqr_system_t lsys = sys->J.sys;
  FILE *fp = LIF(sys);

  oldtiming = g_linsolqr_timing;
  g_linsolqr_timing =LINTIME;
  linsolqr_factor(lsys,sys->J.fm);          /* factor */
  g_linsolqr_timing = oldtiming;

  sys->J.rank = linsolqr_rank(lsys);
  sys->J.singular = FALSE;
  row_rank_defect = sys->J.reg.row.high -
    sys->J.reg.row.low+1 - sys->J.rank;
  if( row_rank_defect > 0 ) {
    int32 row,krow;
    mtx_sparse_t *uprows=NULL;
    sys->J.singular = TRUE;
    uprows = linsolqr_unpivoted_rows(lsys);
    if (uprows !=NULL) {
      for( krow=0; krow < uprows->len ; krow++ ) {
        int32 org_row;
        struct rel_relation *rel;

        org_row = uprows->idata[krow];
        row = mtx_org_to_row(sys->J.mtx,org_row);
        rel = sys->rlist[org_row];
        FPRINTF(fp,"%-40s ---> ","Relation not pivoted");
        print_rel_name(fp,sys,rel);
        PUTC('\n',fp);

        /*
         *  assign zeros to the corresponding weights
         *  so that subsequent calls to "scale_residuals"
         *  will only measure the pivoted equations.
         */
        sys->weights.vec[row] = 0.0;
        sys->residuals.vec[row] = 0.0;
        sys->residuals.accurate = FALSE;
        mtx_mult_row(sys->J.mtx,row,0.0,&(sys->J.reg.col));
      }
      mtx_destroy_sparse(uprows);
    }
    if( !sys->residuals.accurate ) {
      square_norm( &(sys->residuals) );
      sys->residuals.accurate = TRUE;
      sys->update.weights = 0;  /* re-compute weights next iteration. */
    }
  }
  if( sys->J.rank < sys->J.reg.col.high-sys->J.reg.col.low+1 ) {
    int32 col,kcol;
    mtx_sparse_t *upcols=NULL;
    if (NOTNULL(upcols)) {
      for( kcol=0; upcols != NULL && kcol < upcols->len ; kcol++ ) {
        int32 org_col;
        struct var_variable *var;

        org_col = upcols->idata[kcol];
        col = mtx_org_to_col(sys->J.mtx,org_col);
        var = sys->vlist[org_col];
        FPRINTF(fp,"%-40s ---> ","Variable not pivoted");
        print_var_name(fp,sys,var);
        PUTC('\n',fp);
        /*
         *  If we're not optimizing (everything should be
         *  pivotable) or this was one of the dependent variables,
         *  consider this variable as if it were fixed.
         */
        if( col <= sys->J.reg.col.high ) {
          mtx_mult_col(sys->J.mtx,col,0.0,&(sys->J.reg.row));
        }
      }
      mtx_destroy_sparse(upcols);
    }
  }
  if (SHOW_LESS_IMPT) {
    FPRINTF(LIF(sys),"%-40s ---> %d (%s)\n","Jacobian rank", sys->J.rank,
            sys->J.singular ? "deficient":"full");
    FPRINTF(LIF(sys),"%-40s ---> %g\n","Smallest pivot",
            linsolqr_smallest_pivot(sys->J.sys));
  }
  return row_rank_defect;
}


/*
 *  Calculates just the jacobian RHS.  This function should be used to
 *  supplement calculation of the jacobian.  The vector vec must
 *  already be calculated and scaled so as to simply be added to the
 *  rhs.  Caller is responsible for initially zeroing the rhs vector.
 */
static void calc_rhs(slv4_system_t sys, struct vector_data *vec,
                     real64 scalar, boolean transpose)
{
  if( transpose ) {     /* vec is indexed by col */
    int32 col;
    for( col=vec->rng->low; col<=vec->rng->high; col++ ) {
      sys->J.rhs[mtx_col_to_org(sys->J.mtx,col)] += scalar*vec->vec[col];
    }
  } else {              /* vec is indexed by row */
    int32 row;
    for( row=vec->rng->low; row<=vec->rng->high; row++ ) {
      sys->J.rhs[mtx_row_to_org(sys->J.mtx,row)] += scalar*vec->vec[row];
    }
  }
  linsolqr_rhs_was_changed(sys->J.sys,sys->J.rhs);
}

/*
 *  Calculate the gamma vector.
 */
static void calc_gamma( slv4_system_t sys)
{
   if( sys->gamma.accurate )
      return;

   matrix_product(sys->J.mtx, &(sys->residuals),
                  &(sys->gamma), -1.0, TRUE);
   square_norm( &(sys->gamma) );
   sys->gamma.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Gamma:  ");
   debug_out_vector(LIF(sys),sys,&(sys->gamma));
#endif
}

/*
 *  Calculate the Jgamma vector.
 */
static void calc_Jgamma( slv4_system_t sys)
{
   if( sys->Jgamma.accurate )
      return;

   matrix_product(sys->J.mtx, &(sys->gamma),
                  &(sys->Jgamma), 1.0, FALSE);
   square_norm( &(sys->Jgamma) );
   sys->Jgamma.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Jgamma:  ");
   debug_out_vector(LIF(sys),sys,&(sys->Jgamma));
#endif
}

/*
 *  Computes a step to solve the linearized equations.
 */
static void calc_newton( slv4_system_t sys)
{
   linsolqr_system_t lsys = sys->J.sys;
   int32 col;

   if( sys->newton.accurate )
      return;

   sys->J.rhs = linsolqr_get_rhs(lsys,0);
   mtx_zero_real64(sys->J.rhs,sys->cap);
   calc_rhs(sys, &(sys->residuals), -1.0, FALSE);
   linsolqr_solve(lsys,sys->J.rhs);
   col = sys->newton.rng->low;
   for( ; col <= sys->newton.rng->high; col++ ) {
     sys->newton.vec[col] =
       linsolqr_var_value(lsys,sys->J.rhs,mtx_col_to_org(sys->J.mtx,col));
   }
   if (SAVLIN) {
     FILE *ldat;
     int32 ov;
     sprintf(savlinfilename,"%s%d",savlinfilebase,savlinnum++);
     ldat=fopen(savlinfilename,"w");
     FPRINTF(ldat,"================= resids (orgrowed) itn %d =====\n",
             sys->s.iteration);
     debug_write_array(ldat,sys->J.rhs,sys->cap);
     FPRINTF(ldat,"================= vars (orgcoled) ============\n");
     for(ov=0 ; ov < sys->cap; ov++ )
       FPRINTF(ldat,"%.20g\n",linsolqr_var_value(lsys,sys->J.rhs,ov));
     fclose(ldat);
   }
   square_norm( &(sys->newton) );
   sys->newton.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Newton:  ");
   debug_out_vector(LIF(sys),sys,&(sys->newton));
#endif
}


/*
 *  Calculate the 1st order descent direction for phi
 *  in the variables.
 */
static void calc_varstep1( slv4_system_t sys)
{
  if( sys->varstep1.accurate ) {
      return;
  }

   copy_vector(&(sys->gamma),&(sys->varstep1));
   sys->varstep1.norm2 = sys->gamma.norm2;
   sys->varstep1.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Varstep1:  ");
   debug_out_vector(LIF(sys),sys,&(sys->varstep1));
#endif
}


/*
 *  Calculate the 2nd order descent direction for phi
 *  in the variables.
 */
static void calc_varstep2( slv4_system_t sys)
{
   if( sys->varstep2.accurate )
      return;
      copy_vector(&(sys->newton),&(sys->varstep2));
      sys->varstep2.norm2 = sys->newton.norm2;

   sys->varstep2.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Varstep2:  ");
   debug_out_vector(LIF(sys),sys,&(sys->varstep2));
#endif
}


/*
 *  Computes the global minimizing function Phi.
 */
static void calc_phi( slv4_system_t sys)
{
  sys->phi = 0.5*sys->residuals.norm2;

}

/*
 *  OK.  Here's where we compute the actual step to be taken.  It will
 *  be some linear combination of the 1st order and 2nd order steps.
 */

typedef real64 sym_2x2_t[3];        /* Stores symmetric 2x2 matrices */

struct parms_t {
   real64 low,high,guess;           /* Used to search for parameter */
};

struct calc_step_vars {
   sym_2x2_t coef1, coef2;
   real64 rhs[2];   /* RHS for 2x2 system */
   struct parms_t parms;
   real64 alpha1, alpha2;
   real64 error;    /* Error between step norm and sys->maxstep */
};


/*
 *  Calculates 2x2 system (coef1,coef2,rhs).
 */
static void calc_2x2_system(slv4_system_t sys, struct calc_step_vars *vars)
{
   vars->coef1[0] = (2.0*sys->phi/sys->newton.norm2)*
      calc_sqrt_D0(sys->newton.norm2)/calc_sqrt_D0(sys->gamma.norm2);
   vars->coef1[1] = 1.0;
   vars->coef1[2] = (sys->Jgamma.norm2/sys->gamma.norm2)*
     calc_sqrt_D0(sys->newton.norm2)/calc_sqrt_D0(sys->gamma.norm2);

   vars->coef2[0] = 1.0;
   vars->coef2[1] = 2.0*sys->phi/
      calc_sqrt_D0(sys->newton.norm2)/calc_sqrt_D0(sys->gamma.norm2);
   vars->coef2[2] = 1.0;

   vars->rhs[0] = 2.0*sys->phi/
      sys->maxstep/calc_sqrt_D0(sys->gamma.norm2);
   vars->rhs[1] = calc_sqrt_D0(sys->newton.norm2)/sys->maxstep;
}

/*
 *  Determines alpha1 and alpha2 from the parameter (guess).
 */
static void coefs_from_parm( slv4_system_t sys, struct calc_step_vars *vars)
{

   sym_2x2_t coef;     /* Actual coefficient matrix */
   real64 det;   /* Determinant of coefficient matrix */
   int i;

   for( i=0 ; i<3 ; ++i ) coef[i] =
      vars->coef1[i] + vars->parms.guess * vars->coef2[i];
   det = coef[0]*coef[2] - coef[1]*coef[1];
   if( det < 0.0 )
      FPRINTF(MIF(sys),"%-40s ---> %g\n",
              "    Unexpected negative determinant!",det);
   if( det <= DETZERO ) {
      /*
       *  varstep2 and varstep1 are essentially parallel:
       *  adjust length of either
       */
      vars->alpha2 = 0.0;
      vars->alpha1 = 1.0;
   } else {
      vars->alpha2  = (vars->rhs[0]*coef[2] - vars->rhs[1]*coef[1])/det;
      vars->alpha1 = (vars->rhs[1]*coef[0] - vars->rhs[0]*coef[1])/det;
   }
}


/*
 *  Computes step vector length based on 1st order and 2nd order
 *  vectors and their coefficients.
 */
static real64 step_norm2( slv4_system_t sys, struct calc_step_vars *vars)
{
   return sys->maxstep*sys->maxstep*
      (vars->alpha2 * vars->alpha2 +
       vars->alpha2 * vars->alpha1 * sys->phi/
       calc_sqrt_D0(sys->varstep2.norm2 )/
       calc_sqrt_D0(sys->varstep1.norm2 ) +
       vars->alpha1 * vars->alpha1);
}

/*
 *  Re-guesses the parameters based on
 *  step size vs. target value.
 */
static void adjust_parms( slv4_system_t sys, struct calc_step_vars *vars)
{
   vars->error = (calc_sqrt_D0(step_norm2(sys,vars))/sys->maxstep) - 1.0;
   if( vars->error > 0.0 ) {
      /* Increase parameter (to decrease step length) */
      vars->parms.low = vars->parms.guess;
      vars->parms.guess = (vars->parms.high>3.0*vars->parms.guess)
         ? 2.0*vars->parms.guess
            : 0.5*(vars->parms.low + vars->parms.high);
   } else {
      /* Decrease parameter (to increase step norm) */
      vars->parms.high = vars->parms.guess;
      vars->parms.guess = 0.5*(vars->parms.low + vars->parms.high);
   }
}

/*
 *  Computes the step based on the coefficients in vars.
 */
static void compute_step( slv4_system_t sys, struct calc_step_vars *vars)
{
   int32 row,col;
   real64 tot1_norm2, tot2_norm2;

   tot1_norm2 = sys->varstep1.norm2;
   tot2_norm2 = sys->varstep2.norm2;
   if( !sys->varstep.accurate ) {
      for( col=sys->varstep.rng->low ; col<=sys->varstep.rng->high ; ++col )
         if( (vars->alpha2 == 1.0) && (vars->alpha1 == 0.0) ) {
            sys->varstep.vec[col] = sys->maxstep *
               sys->varstep2.vec[col]/calc_sqrt_D0(tot2_norm2);
         } else if( (vars->alpha2 == 0.0) && (vars->alpha1 == 1.0) ) {
            sys->varstep.vec[col] = sys->maxstep *
               sys->varstep1.vec[col]/calc_sqrt_D0(tot1_norm2);
         } else if( (vars->alpha2 != 0.0) && (vars->alpha1 != 0.0) ) {
            sys->varstep.vec[col] = sys->maxstep*
               (vars->alpha2*sys->varstep2.vec[col]/calc_sqrt_D0(tot2_norm2) +
                vars->alpha1*sys->varstep1.vec[col]/calc_sqrt_D0(tot1_norm2));
         }
      sys->varstep.accurate = TRUE;
   }
#if DEBUG
   FPRINTF(LIF(sys),"Varstep:  ");
   debug_out_vector(LIF(sys),sys,&(sys->varstep));

#endif
}

/*
 *  Calculates step vector, based on sys->maxstep, and the varstep2/
 *  varstep1.  Nothing is assumed to be
 *  calculated, except the weights and the jacobian (scaled).  Also,
 *  the step is not checked for legitimacy.
 *  NOTE: the step is scaled.
 */
static void calc_step( slv4_system_t sys, int minor)
{

   struct calc_step_vars vars;
   real64 tot1_norm2, tot2_norm2;

   if( sys->varstep.accurate  )
      return;
   if (SHOW_LESS_IMPT) {
     FPRINTF(LIF(sys),"\n%-40s ---> %d\n", "    Step trial",minor);
   }

   tot1_norm2 = sys->varstep1.norm2;
   tot2_norm2 = sys->varstep2.norm2;
   if( (tot1_norm2 == 0.0) && (tot2_norm2 == 0.0) ) {
      /* Take no step at all */
      vars.alpha1 = 0.0;
      vars.alpha2 = 0.0;
      sys->maxstep = 0.0;
      sys->varstep.norm2 = 0.0;
 

   } else if( (tot2_norm2>0.0)&&(calc_sqrt_D0(tot2_norm2)<=sys->maxstep) ) {
      /* Attempt step in varstep2 direction */
      vars.alpha1 = 0.0;
      vars.alpha2 = 1.0;
      sys->maxstep = calc_sqrt_D0(tot2_norm2);
      sys->varstep.norm2 = calc_sqr_D0(sys->maxstep)*
         sys->varstep2.norm2/tot2_norm2;
 

   } else if( (tot2_norm2==0.0 || sys->s.block.current_size==1) &&
             (tot1_norm2 > 0.0) ) {
      /* Attempt step in varstep1 direction */
      vars.alpha1 = 1.0;
      vars.alpha2 = 0.0;
      if ( (sys->gamma.norm2/sys->Jgamma.norm2)*
          calc_sqrt_D0(sys->gamma.norm2) <= sys->maxstep )
         sys->maxstep = (sys->gamma.norm2/sys->Jgamma.norm2)*
            calc_sqrt_D0(sys->gamma.norm2);
      sys->varstep.norm2 = calc_sqr_D0(sys->maxstep)*
         sys->varstep1.norm2/tot1_norm2;


   } else {
      /* Attempt step in varstep1-varstep2 direction */
      vars.parms.low = 0.0;
      vars.parms.high = MAXDOUBLE;
      vars.parms.guess = 1.0;
      calc_2x2_system(sys,&vars);
      do {
         coefs_from_parm(sys, &vars);
         adjust_parms(sys, &vars);
      } while( fabs(vars.error) > STEPSIZEERR_MAX &&
              vars.parms.high - vars.parms.low > PARMRNG_MIN );
      if (SHOW_LESS_IMPT) {
        FPRINTF(LIF(sys),"%-40s ---> %g\n",
                "    parameter high", vars.parms.high);
        FPRINTF(LIF(sys),"%-40s ---> %g\n",
                "    parameter low", vars.parms.low);
        FPRINTF(LIF(sys),"%-40s ---> %g\n",
                "    Error in step length", vars.error);
      }
      sys->varstep.norm2 = step_norm2(sys, &vars);

   }

   if (SHOW_LESS_IMPT) {
     FPRINTF(LIF(sys),"%-40s ---> %g\n", "    Alpha1 coefficient (normalized)",
             vars.alpha1);
     FPRINTF(LIF(sys),"%-40s ---> %g\n", "    Alpha2 coefficient (normalized)",
             vars.alpha2);
   }
   compute_step(sys,&vars);
   return;

}


/*
 *  Variable values maintenance
 *  ---------------------------
 *     restore_variables(sys)
 *     coef = required_coef_to_stay_inbounds(sys)
 *     apply_step(sys,coef)
 *     step_accepted(sys)
 *     change_maxstep(sys,maxstep)
 */

/*
 *  Restores the values of the variables before applying
 *  a step.
 */
static void restore_variables( slv4_system_t sys)
{
   int32 col;
   real64 *vec;
   vec = (sys->nominals.vec);
   for( col = sys->J.reg.col.low; col <= sys->J.reg.col.high; col++ ) {
      struct var_variable *var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
      var_set_value(var,sys->variables.vec[col]*vec[col]);
   }
}


/*
 *  Calculates the maximum fraction of the step which can be
 *  taken without making negative the complementary vars.  
 *  It is assumed that the current complementary variable
 *  is positive.  The step must be calculated.
 */
static real64 factor_for_complementary_vars( slv4_system_t sys) 
{
   real64 factor, minfactor;
   struct var_variable *var;
   real64 dx,val,bnd;
   int32 col;
   real64 *vec;

   vec = (sys->nominals.vec);

   minfactor = 1.0;
   factor = 1.0;
   for( col=sys->varstep.rng->low; col <= sys->varstep.rng->high; col++ ) {
     var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
     val = var_value(var);
     if (var_complementary(var) && (!var_fixed(var))) {
       dx = sys->varstep.vec[col] * vec[col];
       bnd = 0.0;
       if( val + dx < bnd ) {
         factor = MIN((bnd-val)/dx, 1.0);
         if (factor < 1.0) {
#if DEBUG_COMPLEMENTARY_VAR
           FPRINTF(ASCERR,"Negative Complementary Variable : \n");
           print_var_name(ASCERR,sys,var); 
           FPRINTF(ASCERR,"\n");
           FPRINTF(ASCERR,"factor = %f \n",factor);
#endif /* DEBUG_COMPLEMENTARY_VAR */
     }
         if( factor < minfactor ) {
           minfactor = factor;
     }
       }
     }
   }
#if DEBUG_COMPLEMENTARY_VAR
  FPRINTF(ASCERR,"Minimum factor for complementary vars = %f \n",minfactor); 
#endif /* DEBUG_COMPLEMENTARY_VAR */
  return minfactor;
}


/*
 *  Calculates the maximum fraction of the step which can be
 *  taken without going out of bounds.  If the entire step can be
 *  taken, 1.0 is returned.  Otherwise a value less than 1 is
 *  returned.  It is assumed that the current variable values
 *  are within their bounds.  The step must be calculated.
 */
static real64 required_coef_to_stay_inbounds( slv4_system_t sys)
{
   real64 mincoef;
   int32 col;
   real64 *vec;
   vec = (sys->nominals.vec);

   if( sys->p.ignore_bounds )
      return(1.0);

   mincoef = 1.0;
   for( col=sys->varstep.rng->low; col <= sys->varstep.rng->high; col++ ) {
     struct var_variable *var;
     real64 coef,dx,val,bnd;
     var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
     coef = 1.0;
     dx = sys->varstep.vec[col] * vec[col];
     bnd = var_upper_bound(var);
     if( (val=var_value(var)) + dx > bnd )
       coef = MIN((bnd-val)/dx, 1.0);
     bnd = var_lower_bound(var);
     if( val + dx < bnd )
       coef = MIN((bnd-val)/dx, 1.0);
     if( coef < mincoef )
       mincoef = coef;
   }
   if (mincoef < 1.0) {
#if DEBUG_COMPLEMENTARY_VAR
     FPRINTF(ASCERR,"Coefficient to stay in bounds = %f \n",mincoef); 
#endif /* DEBUG_COMPLEMENTARY_VAR */   
   }
   return(mincoef);
}

/*
 *  Adds sys->varstep to the variable values in block: projecting
 *  near bounds.
 */
static void apply_step( slv4_system_t sys)
{
   FILE *lif = LIF(sys);
   int nproj = 0;
   real64 bounds_coef = 1.0;
   int32 col;
   real64 *vec;
   real64 factor;
   vec = (sys->nominals.vec);

   if (TRUNCATE_COMP || TRUNCATE_ALL) {
     factor = factor_for_complementary_vars(sys);
   }

   if (TRUNCATE && (!sys->p.ignore_bounds))
      bounds_coef = required_coef_to_stay_inbounds(sys);

   if (TRUNCATE_COMP || TRUNCATE_ALL) {
     if ((bounds_coef < 1.0) && (factor < bounds_coef)) {
       bounds_coef = factor;
     }
   }
 
   for( col=sys->varstep.rng->low; col <= sys->varstep.rng->high; col++ ) {
      struct var_variable *var;
      real64 dx,val,bnd;
      var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
      dx = vec[col]*sys->varstep.vec[col];
      val = var_value(var);

      if (TRUNCATE_ALL) {
        dx = dx*TOWARD_COMP_BOUNDS*factor;
        sys->varstep.vec[col] = dx/vec[col];
      } else {
        if (TRUNCATE_COMP) {
          if ((var_complementary(var)) && (!var_fixed(var))) {
            dx = dx*TOWARD_COMP_BOUNDS*factor;
            sys->varstep.vec[col] = dx/vec[col];
          }
        }
      }

      if (bounds_coef < 1.0 && TRUNCATE) {
         dx = dx*TOWARD_BOUNDS*bounds_coef;
         sys->varstep.vec[col] = dx/vec[col];
    } else {  
          if( !sys->p.ignore_bounds ) {
            if( val + dx > (bnd=var_upper_bound(var)) ) {
               dx = TOWARD_BOUNDS*(bnd-val);
               sys->varstep.vec[col] = dx/vec[col];
               if (SHOW_LESS_IMPT) {
                 FPRINTF(lif,"%-40s ---> ",
                         "    Variable projected to upper bound");
                 print_var_name(lif,sys,var); PUTC('\n',lif);
               }
               ++nproj;
            } else if( val + dx < (bnd=var_lower_bound(var)) ) {
               dx = TOWARD_BOUNDS*(bnd-val);
               sys->varstep.vec[col] = dx/vec[col];
               if (SHOW_LESS_IMPT) {
                 FPRINTF(lif,"%-40s ---> ",
                         "    Variable projected to lower bound");
                 print_var_name(lif,sys,var); PUTC('\n',lif);
               }
               ++nproj;
            }
         }
    }
      var_set_value(var,val+dx);
   }

   if( !sys->p.ignore_bounds ) {
      if (nproj > 0) {
         square_norm(&(sys->varstep));
         sys->progress = calc_sqrt_D0
            (calc_sqrt_D0((sys->varstep.norm2 )*
                          (sys->varstep1.norm2 )));
         if (SHOW_LESS_IMPT) {
           FPRINTF(lif,"%-40s ---> %g\n", "    Projected step length (scaled)",
           calc_sqrt_D0(sys->varstep.norm2));
           FPRINTF(lif,"%-40s ---> %g\n",
                   "    Projected progress", sys->progress);
         }
      }
      if (bounds_coef < 1.0 && TRUNCATE) {
         square_norm(&(sys->varstep));
         if (SHOW_LESS_IMPT) {
            FPRINTF(lif,"%-40s ---> %g\n",
                    "    Truncated step length (scaled)",
                    calc_sqrt_D0(sys->varstep.norm2 ));
         }
         sys->progress = calc_sqrt_D0
            (calc_sqrt_D0((sys->varstep.norm2 )*
                          (sys->varstep1.norm2 )));
            (calc_sqrt_D0(sys->varstep.norm2*sys->varstep1.norm2));
         if (SHOW_LESS_IMPT) {
           FPRINTF(lif,"%-40s ---> %g\n",
                   "    Truncated progress", sys->progress);
         }
      }
   }

   /* Allow weighted residuals to be recalculated at new point */
   sys->residuals.accurate = FALSE;

   return;
}


/*
 *  This function should be called when the step is accepted.
 */
static void step_accepted( slv4_system_t sys)
{
   /* Maintain update status on jacobian and weights */
  if (--(sys->update.jacobian) <= 0) {
      sys->J.accurate = FALSE;
  }

   sys->variables.accurate = FALSE;
   sys->newton.accurate = FALSE;
   sys->gamma.accurate = FALSE;
   sys->Jgamma.accurate = FALSE;
   sys->varstep1.accurate = FALSE;
   sys->varstep2.accurate = FALSE;
   sys->varstep.accurate = FALSE;
}

/*
 *  This function changes sys->maxstep to the given number and should be
 *  called whenever sys->maxstep is to be changed.
 */
static void change_maxstep( slv4_system_t sys, real64 maxstep)
{
   sys->maxstep = maxstep;
   sys->varstep.accurate = FALSE;
}


/*
 *  Block routines
 *  --------------
 *     feas = block_feasible(sys)
 *     move_to_next_block(sys)
 *     find_next_unconverged_block(sys)
 */

/*
 *  Returns TRUE if the current block is feasible, FALSE otherwise.
 *  It is assumed that the residuals have been computed.
 */
static boolean block_feasible( slv4_system_t sys)
{
   int32 row;

   if( !sys->s.calc_ok )
      return(FALSE);

   for( row = sys->J.reg.row.low; row <= sys->J.reg.row.high; row++ ) {
      struct rel_relation *rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
      if( !rel_satisfied(rel) ) return FALSE;
   }
   return TRUE;
}

/*
 *  Moves on to the next block, updating all of the solver information.
 *  To move to the first block, set sys->s.block.current_block to -1 before
 *  calling.  If already at the last block, then sys->s.block.current_block
 *  will equal the number of blocks and the system will be declared
 *  converged.  Otherwise, the residuals for the new block will be computed
 *  and sys->s.calc_ok set according.
 */
static void move_to_next_block( slv4_system_t sys)
{
  struct var_variable *var;
  struct rel_relation *rel;
  int32 row;
  int32 col;
  int32 ci;

  if( sys->s.block.current_block >= 0 ) {

    /* Record cost accounting info here. */
    ci=sys->s.block.current_block;
    sys->s.cost[ci].size    =   sys->s.block.current_size;
    sys->s.cost[ci].iterations  =   sys->s.block.iteration;
    sys->s.cost[ci].funcs   =   sys->s.block.funcs;
    sys->s.cost[ci].jacs    =   sys->s.block.jacs;
    sys->s.cost[ci].functime    =   sys->s.block.functime;
    sys->s.cost[ci].jactime =   sys->s.block.jactime;
    sys->s.cost[ci].time    =   sys->s.block.cpu_elapsed;
    sys->s.cost[ci].resid   =   sys->s.block.residual;

    /* De-initialize previous block */
    if (SHOW_LESS_IMPT && (sys->s.block.current_size >1 ||
        LIFDS)) {
      FPRINTF(LIF(sys),"Block %d converged.\n",
              sys->s.block.current_block);
    }
    for( col=sys->J.reg.col.low; col <= sys->J.reg.col.high; col++ ) {
      var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
      var_set_in_block(var,FALSE);
    }
    for( row=sys->J.reg.row.low; row <= sys->J.reg.row.high; row++ ) {
      rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
      rel_set_in_block(rel,FALSE);
    }
    sys->s.block.previous_total_size += sys->s.block.current_size;
  }

  sys->s.block.current_block++;
  if( sys->s.block.current_block < sys->s.block.number_of ) {
    boolean ok;

    /* Initialize next block */

      sys->J.reg =
        (slv_get_solvers_blocks(SERVER))->block[sys->s.block.current_block];


    row = sys->J.reg.row.high - sys->J.reg.row.low + 1;
    col = sys->J.reg.col.high - sys->J.reg.col.low + 1;
    sys->s.block.current_size = MAX(row,col);

    sys->s.block.iteration = 0;
    sys->s.block.cpu_elapsed = 0.0;
    sys->s.block.functime = 0.0;
    sys->s.block.jactime = 0.0;
    sys->s.block.funcs = 0;
    sys->s.block.jacs = 0;

    if(SHOW_LESS_IMPT && (LIFDS ||
      sys->s.block.current_size > 1)) {
      debug_delimiter(LIF(sys));
      debug_delimiter(LIF(sys));
    }
    if(SHOW_LESS_IMPT && LIFDS) {
      FPRINTF(LIF(sys),"\n%-40s ---> %d in [%d..%d]\n",
              "Current block number", sys->s.block.current_block,
              0, sys->s.block.number_of-1);
      FPRINTF(LIF(sys),"%-40s ---> %d\n", "Current block size",
        sys->s.block.current_size);
    }
    sys->s.calc_ok = TRUE;

    if( !(ok = calc_objective(sys)) ) {
         FPRINTF(MIF(sys),"Objective calculation errors detected.\n");
    }
    if(SHOW_LESS_IMPT && sys->obj) {
      FPRINTF(LIF(sys),"%-40s ---> %g\n", "Objective", sys->objective);
    }
    sys->s.calc_ok = sys->s.calc_ok && ok;

    if (!(sys->p.ignore_bounds) ) {
      slv_ensure_bounds(SERVER, sys->J.reg.col.low,
                        sys->J.reg.col.high,MIF(sys));
    }

    sys->residuals.accurate = FALSE;
    if( !(ok = calc_residuals(sys)) ) {
      FPRINTF(MIF(sys),
        "Residual calculation errors detected in move_to_next_block.\n");
    }
    if( SHOW_LESS_IMPT &&
        (sys->s.block.current_size >1 ||
         LIFDS) ) {
      FPRINTF(LIF(sys),"%-40s ---> %g\n", "Residual norm (unscaled)",
        sys->s.block.residual);
    }
    sys->s.calc_ok = sys->s.calc_ok && ok;

    /* Must be updated as soon as required */
    sys->J.accurate = FALSE;
    sys->update.weights = 0;
    sys->update.nominals = 0;
    sys->update.relnoms = 0;
    sys->update.iterative = 0;
    sys->variables.accurate = FALSE;
    sys->newton.accurate = FALSE;
    sys->gamma.accurate = FALSE;
    sys->Jgamma.accurate = FALSE;
    sys->varstep1.accurate = FALSE;
    sys->varstep2.accurate = FALSE;
    sys->varstep.accurate = FALSE;

  } else {
    boolean ok;
    /*
     *  Before we claim convergence, we must check if we left behind
     *  some unassigned relations.  If and only if they happen to be
     *  satisfied at the current point, convergence has been obtained.
     *
     *  Also insures that all included relations have valid residuals.
     *  Included inequalities will have correct residuals.
     *  Unsatisfied included inequalities cause inconsistency.
     *
     *  This of course ignores that fact an objective function might
     *  be present.  Then, feasibility isn't enough, is it now.
     */
    if( sys->s.struct_singular ) {
       /* black box w/singletons provoking bug here, maybe */
      sys->s.block.current_size = sys->rused - sys->rank;
      if(SHOW_LESS_IMPT) {
        debug_delimiter(LIF(sys));
        FPRINTF(LIF(sys),"%-40s ---> %d\n", "Unassigned Relations",
                sys->s.block.current_size);
      }
      sys->J.reg.row.low = sys->J.reg.col.low = sys->rank;
      sys->J.reg.row.high = sys->J.reg.col.high = sys->rused - 1;
      sys->residuals.accurate = FALSE;
      if( !(ok=calc_residuals(sys)) ) {
         FPRINTF(MIF(sys),
           "Residual calculation errors detected in leftover equations.\n");
      }
      if(SHOW_LESS_IMPT) {
        FPRINTF(LIF(sys),"%-40s ---> %g\n", "Residual norm (unscaled)",
                sys->s.block.residual);
      }
      if( block_feasible(sys) ) {
        if(SHOW_LESS_IMPT) {
          FPRINTF(LIF(sys),"\nUnassigned relations ok. You lucked out.\n");
        }
        sys->s.converged = TRUE;
      } else {
        if(SHOW_LESS_IMPT) {
          FPRINTF(LIF(sys),"\nProblem inconsistent:  %s.\n",
                  "Unassigned relations not satisfied");
        }
        sys->s.inconsistent = TRUE;
      }
      if(SHOW_LESS_IMPT) {
        debug_delimiter(LIF(sys));
      }
    } else {
      sys->s.converged = TRUE;
    }
    /* nearly done checking. Must verify included inequalities if
       we think equalities are ok. */
    if (sys->s.converged) {
      sys->s.inconsistent=(!calc_inequalities(sys));
    }
  }
}


/*
 *  Calls the appropriate reorder function on a block
 */
static void reorder_new_block(slv4_system_t sys)
{
  int32 method;
  if( sys->s.block.current_block < sys->s.block.number_of ) {
    if (strcmp(REORDER_OPTION,"SPK1") == 0) {
      method = 2;
    } else {
      method = 1;
    }

    if( sys->s.block.current_block <= sys->s.block.current_reordered_block &&
       sys->s.cost[sys->s.block.current_block].reorder_method == method &&
       sys->s.block.current_block >= 0 ) {
#if DEBUG
      FPRINTF(stderr,"YOU JUST AVOIDED A REORDERING\n");
#endif
      slv_set_up_block(SERVER,sys->s.block.current_block);
      /* tell linsol to bless it and get on with things */
      linsolqr_reorder(sys->J.sys,&(sys->J.reg),natural);
      return; /*must have been reordered since last system build*/
    }

    /* Let the slv client function take care of reordering things
     * and setting in block flags.
     */
    if (strcmp(REORDER_OPTION,"SPK1") == 0) {
      sys->s.cost[sys->s.block.current_block].reorder_method = 2;
      slv_spk1_reorder_block(SERVER,sys->s.block.current_block,1);
    } else if (strcmp(REORDER_OPTION,"TEAR_DROP") == 0) {
      sys->s.cost[sys->s.block.current_block].reorder_method = 1;
      slv_tear_drop_reorder_block(SERVER,sys->s.block.current_block,
                                  CUTOFF,
                  0,mtx_SPK1);
/* khack: try tspk1 for transpose case */
    } else if (strcmp(REORDER_OPTION,"OVER_TEAR") == 0) {
      sys->s.cost[sys->s.block.current_block].reorder_method = 1;
      slv_tear_drop_reorder_block(SERVER,sys->s.block.current_block,
                                  CUTOFF,
                  1,mtx_SPK1);
    } else {
      sys->s.cost[sys->s.block.current_block].reorder_method = 1;
      FPRINTF(MIF(sys),"QRSlv called with unknown reorder option\n");
      FPRINTF(MIF(sys),"QRSlv using single edge tear drop (TEAR_DROP).\n");
      slv_tear_drop_reorder_block(SERVER,sys->s.block.current_block,
                                  CUTOFF,0,mtx_SPK1);
    }
    /* tell linsol to bless it and get on with things */
    linsolqr_reorder(sys->J.sys,&(sys->J.reg),natural);
    if (sys->s.block.current_block > sys->s.block.current_reordered_block) {
      sys->s.block.current_reordered_block = sys->s.block.current_block;
    }
  }
}

/*
 *  Moves to next unconverged block, assuming that the current block has
 *  converged (or is -1, to start).
 */
static void find_next_unconverged_block( slv4_system_t sys)
{
   do {
     move_to_next_block(sys);
#if DEBUG
     debug_out_var_values(stderr,sys);
     debug_out_rel_residuals(stderr,sys);
#endif
   } while( !sys->s.converged && block_feasible(sys));
   reorder_new_block(sys);
}


/*
 *  Iteration begin/end routines
 *  ----------------------------
 *     iteration_begins(sys)
 *     iteration_ends(sys)
 */

/*
 *  Prepares sys for entering an iteration, increasing the iteration counts
 *  and starting the clock.
 */
static void iteration_begins( slv4_system_t sys)
{
   sys->clock = tm_cpu_time();
   ++(sys->s.block.iteration);
   ++(sys->s.iteration);
   if(SHOW_LESS_IMPT&& (sys->s.block.current_size >1 ||
      LIFDS)) {
     FPRINTF(LIF(sys),"\n%-40s ---> %d\n",
             "Iteration", sys->s.block.iteration);
     FPRINTF(LIF(sys),"%-40s ---> %d\n",
             "Total iteration", sys->s.iteration);
   }
}

/*
 *  Prepares sys for exiting an iteration, stopping the clock and recording
 *  the cpu time.
 */
static void iteration_ends( slv4_system_t sys)
{
   double cpu_elapsed;   /* elapsed this iteration */

   cpu_elapsed = (double)(tm_cpu_time() - sys->clock);
   sys->s.block.cpu_elapsed += cpu_elapsed;
   sys->s.cpu_elapsed += cpu_elapsed;
   if(SHOW_LESS_IMPT && (sys->s.block.current_size >1 ||
         LIFDS)) {
     FPRINTF(LIF(sys),"%-40s ---> %g\n",
            "Elapsed time", sys->s.block.cpu_elapsed);
     FPRINTF(LIF(sys),"%-40s ---> %g\n",
            "Total elapsed time", sys->s.cpu_elapsed);
   }
}

/*
 *  Updates the solver status.
 */
static void update_status( slv4_system_t sys)
{
   boolean unsuccessful;

   if( !sys->s.converged ) {
      sys->s.time_limit_exceeded =
         (sys->s.block.cpu_elapsed >= TIME_LIMIT);
      sys->s.iteration_limit_exceeded =
         (sys->s.block.iteration >= ITER_LIMIT);
   }

   unsuccessful = sys->s.diverged || sys->s.inconsistent ||
      sys->s.iteration_limit_exceeded || sys->s.time_limit_exceeded;

   sys->s.ready_to_solve = !unsuccessful && !sys->s.converged;
   sys->s.ok = !unsuccessful && sys->s.calc_ok && !sys->s.struct_singular;
}

static
int32 slv4_get_default_parameters(slv_system_t server, SlvClientToken asys,
                  slv_parameters_t *parameters)
{
  slv4_system_t sys;
  union parm_arg lo,hi,val;
  struct slv_parameter *new_parms = NULL;
  int32 make_macros = 0;

  static char *factor_names[] = {
    "SPK1/RANKI","SPK1/RANKI+ROW",
    "Fast-SPK1/RANKI","Fast-SPK1/RANKI+ROW",
    "Fastest-SPK1/MR-RANKI","CondQR","CPQR"
/*    ,"GAUSS","GAUSS_EASY"  currently only works for ken */
  };
  static char *reorder_names[] = {
    "SPK1","TEAR_DROP","OVER_TEAR"
  };
  static char *converge_names[] = {
    "ABSOLUTE","RELNOM_SCALE"
  };
  static char *scaling_names[] = {
    "NONE","ROW_2NORM","RELNOM"
  };

  if (server != NULL && asys != NULL) {
    sys = SLV4(asys);
    make_macros = 1;
  }

#ifndef NDEBUG  /* keep purify from whining on UMR */
  lo.argr = hi.argr = val.argr = 0.0;
#endif

  if (parameters->parms == NULL) {
    /* an external client wants our parameter list.
     * an instance of slv4_system_structure has this pointer
     * already set in slv4_create
     */
    new_parms = (struct slv_parameter *)
      ascmalloc((slv4_PA_SIZE)*sizeof(struct slv_parameter));
    if (new_parms == NULL) {
      return -1;
    }
    parameters->parms = new_parms;
    parameters->dynamic_parms = 1;
  }
  parameters->num_parms = 0;

  /* begin defining parameters */

  slv_define_parm(parameters, bool_parm,
           "ignorebounds","ignore bounds?","ignore bounds?",
           U_p_bool(val,0),U_p_bool(lo,0),U_p_bool(hi,1),-1);
  SLV_BPARM_MACRO(IGNORE_BOUNDS_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "showmoreimportant", "showmoreimportant", "showmoreimportant",
           U_p_bool(val,1),U_p_bool(lo,0),U_p_bool(hi,1),-1);
  SLV_BPARM_MACRO(SHOW_MORE_IMPT_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "rho", "penalty parameter", "penalty parameter",
           U_p_real(val,100),U_p_real(lo, 0),U_p_real(hi,10e100), 1);
  SLV_RPARM_MACRO(RHO_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "partition", "partitioning enabled", "partitioning enabled",
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(PARTITION_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "showlessimportant", "detailed solving info",
               "detailed solving info",
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(SHOW_LESS_IMPT_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "autoresolve", "auto-resolve", "auto-resolve",
           U_p_bool(val,1),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(AUTO_RESOLVE_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "timelimit", "time limit (CPU sec/block)", "time limit (CPU sec/block)",
           U_p_int(val,1500),U_p_int(lo, 1),U_p_int(hi,20000),1);
  SLV_IPARM_MACRO(TIME_LIMIT_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "iterationlimit", "max iterations/block", "max iterations/block",
           U_p_int(val, 30),U_p_int(lo, 1),U_p_int(hi,20000),1);
  SLV_IPARM_MACRO(ITER_LIMIT_PTR,parameters);

  slv_define_parm(parameters,real_parm,
           "stattol","stattol" ,"stattol" ,
           U_p_real(val,1e-6),U_p_real(lo,0),U_p_real(hi,1.0),-1);
  SLV_RPARM_MACRO(STAT_TOL_PTR,parameters);

  slv_define_parm(parameters,real_parm,
           "termtol","termtol" ,"termtol" ,
           U_p_real(val,1e-12),U_p_real(lo,0),U_p_real(hi,1.0),-1);
  SLV_RPARM_MACRO(TERM_TOL_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "singtol", "epsilon (min pivot)", "epsilon (min pivot)",
           U_p_real(val, 1e-12),U_p_real(lo, 1e-12),U_p_real(hi,1.0),1);
  SLV_RPARM_MACRO(SING_TOL_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "pivottol", "condition tolerance", "condition tolerance",
           U_p_real(val, 0.5),U_p_real(lo, 0),U_p_real(hi, 1),1);
  SLV_RPARM_MACRO(PIVOT_TOL_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "feastol", "max residual (absolute)", "max residual (absolute)",
           U_p_real(val, 1e-8),U_p_real(lo, 1e-13),U_p_real(hi,100000.5),1);
  SLV_RPARM_MACRO(FEAS_TOL_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "lifds", "show singletons details", IEX(0),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(LIFDS_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "savlin", "write to file SlvLinsol.dat", IEX(1),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(SAVLIN_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "safe_calc", "safe calculations", IEX(12),
           U_p_bool(val, 1),U_p_bool(lo,0),U_p_bool(hi,1), 2);

  SLV_BPARM_MACRO(SAFE_CALC_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "relnomscale", "calc rel nominals", IEX(2),
           U_p_bool(val, 1),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(RELNOMSCALE_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "cutoff", "block size cutoff (MODEL-based)", IEX(3),
           U_p_int(val, 500),U_p_int(lo,0),U_p_int(hi,20000), 2);
  SLV_IPARM_MACRO(CUTOFF_PTR,parameters);


  slv_define_parm(parameters, int_parm,
           "upjac", "Jacobian update frequency", IEX(4),
           U_p_int(val, 1),U_p_int(lo,0),U_p_int(hi,20000), 3);
  SLV_IPARM_MACRO(UPDATE_JACOBIAN_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "upwts", "Row scaling update frequency", IEX(5),
           U_p_int(val, 1),U_p_int(lo,0),U_p_int(hi,20000), 3);
  SLV_IPARM_MACRO(UPDATE_WEIGHTS_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "upnom", "Column scaling update frequency", IEX(6),
           U_p_int(val, 1000),U_p_int(lo,0),U_p_int(hi,20000), 3);
  SLV_IPARM_MACRO(UPDATE_NOMINALS_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "uprelnom", "Relation nominal update frequency", IEX(13),
           U_p_int(val, 5),U_p_int(lo,0),U_p_int(hi,20000), 3);
  SLV_IPARM_MACRO(UPDATE_RELNOMS_PTR,parameters);

  slv_define_parm(parameters, int_parm,
           "itscalelim", "Iteration lim for iterative scale", IEX(14), 
           U_p_int(val, 10),U_p_int(lo,0),U_p_int(hi,20000), 3);
  SLV_IPARM_MACRO(ITSCALELIM_PTR,parameters);

  slv_define_parm(parameters, char_parm,
           "convopt", "convergence test", "convergence test",
           U_p_string(val,converge_names[0]),
           U_p_strings(lo,converge_names),
           U_p_int(hi,sizeof(converge_names)/sizeof(char *)),1);
  SLV_CPARM_MACRO(CONVOPT_PTR,parameters);

  slv_define_parm(parameters, char_parm,
           "scaleopt", "jacobian scaling option", IEX(15),
           U_p_string(val,scaling_names[1]),
           U_p_strings(lo,scaling_names),
           U_p_int(hi,sizeof(scaling_names)/sizeof(char *)),1);
  SLV_CPARM_MACRO(SCALEOPT_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "reduce", "step reduction on?", IEX(7),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(REDUCE_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "exact", "exact line search", IEX(8),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(EXACT_LINE_SEARCH_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "cncols", "Check poorly scaled columns", IEX(9),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(DUMPCNORM_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "lintime", "Enable linsolqr timing",
               "Enable linsolqr factor timing",
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(LINTIME_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "btrunc", "truncate whole step vector", IEX(10),
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(TRUNCATE_PTR,parameters);

  slv_define_parm(parameters, char_parm,
           "reorder", "reorder method", IEX(11),
           U_p_string(val,reorder_names[0]),
           U_p_strings(lo,reorder_names),
           U_p_int(hi,sizeof(reorder_names)/sizeof(char *)),1);
  SLV_CPARM_MACRO(REORDER_OPTION_PTR,parameters);


  slv_define_parm(parameters, real_parm,
           "toosmall", "default for zero nominal", REX(0),
           U_p_real(val, 1e-8),U_p_real(lo, 1e-12),U_p_real(hi,1.5), 3);
  SLV_RPARM_MACRO(TOO_SMALL_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "cnlow", "smallest allowable column norm", REX(1),
           U_p_real(val, 0.01),U_p_real(lo, 0),U_p_real(hi,100000000.5), 3);
  SLV_RPARM_MACRO(CNLOW_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "cnhigh", "largest allowable column norm", REX(2),
           U_p_real(val, 100.0),U_p_real(lo,0),U_p_real(hi,100000000.5), 3);
  SLV_RPARM_MACRO(CNHIGH_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "tobnds", "fraction move to bounds", REX(3),
           U_p_real(val, 0.95),U_p_real(lo, 0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(TOWARD_BOUNDS_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "tocompbnds", "fraction move to complementary bounds", 
               "fraction move to complementary bounds",
           U_p_real(val, 0.95),U_p_real(lo, 0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(TOWARD_COMP_BOUNDS_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "posdef", "Positive Definite Hessian Check", REX(4),
           U_p_real(val, 0.01),U_p_real(lo,0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(POSITIVE_DEFINITE_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "detzero", "Min newt/grad determinant ||", REX(5),
           U_p_real(val, 1e-8),U_p_real(lo,0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(DETZERO_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "steperrmax", "Step size precision", REX(6),
           U_p_real(val, 1e-4),U_p_real(lo, 1e-10),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(STEPSIZEERR_MAX_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "prngmin", "Parameter range tolerance (in-loop)", REX(7),
           U_p_real(val, 1e-12),U_p_real(lo, 1e-12),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(PARMRNG_MIN_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "mincoef", "'Largest' drop in maxstep allowed", REX(8),
           U_p_real(val, 0.05),U_p_real(lo, 1e-5),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(MIN_COEF_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "maxcoef", "'Smallest' drop in maxstep allowed", REX(9),
           U_p_real(val, 0.99999),U_p_real(lo,0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(MAX_COEF_PTR,parameters);

  slv_define_parm(parameters, real_parm,
           "itscaletol", "Iterative scaling tolerance", REX(10),
           U_p_real(val, 0.99999),U_p_real(lo,0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(ITSCALETOL_PTR,parameters);

  slv_define_parm(parameters, char_parm,
           "bppivoting","linear method","linear method choice",
           U_p_string(val,factor_names[4]),
           U_p_strings(lo,factor_names),
           U_p_int(hi,sizeof(factor_names)/sizeof(char *)),1);
  SLV_CPARM_MACRO(FACTOR_OPTION_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "truncomp", "truncate complementary variables",
               "truncate complementary variables",
           U_p_bool(val, 1),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(TRUNCATE_COMP_PTR,parameters);

  slv_define_parm(parameters, bool_parm,
           "truncall", "truncate all variables", 
               "truncate all variables",
           U_p_bool(val, 0),U_p_bool(lo,0),U_p_bool(hi,1), 2);
  SLV_BPARM_MACRO(TRUNCATE_ALL_PTR,parameters);


  return 1;
}

/*
 *  External routines
 *  -----------------
 *     See slv_client.h
 */

static SlvClientToken slv4_create(slv_system_t server, int *statusindex)
{
  slv4_system_t sys;

  sys = (slv4_system_t)asccalloc(1, sizeof(struct slv4_system_structure) );
  if (sys==NULL) {
    *statusindex = 1;
    return sys;
  }
  SERVER = server;
  sys->p.parms = sys->pa;
  sys->p.dynamic_parms = 0;
  slv4_get_default_parameters(server,(SlvClientToken)sys,&(sys->p));
  sys->integrity = OK;
  sys->presolved = 0;
  sys->p.output.more_important = stdout;
  sys->p.output.less_important = stdout;
  sys->J.old_partition = TRUE;
  sys->p.whose = (*statusindex);
  sys->s.ok = TRUE;
  sys->s.calc_ok = TRUE;
  sys->s.costsize = 0;
  sys->s.cost = NULL; /*redundant, but sanity preserving */
  sys->vlist = slv_get_solvers_var_list(server);
  sys->rlist = slv_get_solvers_rel_list(server);
  sys->obj = slv_get_obj_relation(server);
  if (sys->vlist == NULL) {
    ascfree(sys);
    FPRINTF(stderr,"QRSlv called with no variables.\n");
    *statusindex = -2;
    return NULL; /*_prolly leak here */
  }
  if (sys->rlist == NULL && sys->obj == NULL) {
    ascfree(sys);
    FPRINTF(stderr,"QRSlv called with no relations or objective.\n");
    *statusindex = -1;
    return NULL; /*_prolly leak here */
  }
  /* we don't give a damn about the objective list or the pars or
   * bounds or extrels or any of the other crap.
   */
  slv_check_var_initialization(server);
  *statusindex = 0;
  return((SlvClientToken)sys);

}

static void destroy_matrices( slv4_system_t sys)
{
   if( sys->J.sys ) {
      int count = linsolqr_number_of_rhs(sys->J.sys)-1;
      for( ; count >= 0; count-- ) {
         destroy_array(linsolqr_get_rhs(sys->J.sys,count));
       }
      mtx_destroy(linsolqr_get_matrix(sys->J.sys));
      linsolqr_set_matrix(sys->J.sys,NULL);
      linsolqr_destroy(sys->J.sys);
      sys->J.sys = NULL;
   }
}

static void destroy_vectors( slv4_system_t sys)
{
   destroy_array(sys->nominals.vec);
   destroy_array(sys->weights.vec);
   destroy_array(sys->relnoms.vec);
   destroy_array(sys->variables.vec);
   destroy_array(sys->residuals.vec);
   destroy_array(sys->newton.vec);
   destroy_array(sys->gamma.vec);
   destroy_array(sys->Jgamma.vec);
   destroy_array(sys->varstep1.vec);
   destroy_array(sys->varstep2.vec);
   destroy_array(sys->varstep.vec);
}

static int slv4_eligible_solver(slv_system_t server)
{
  struct rel_relation **rp;
  rel_filter_t rfilter;

  rfilter.matchbits = (REL_INCLUDED | REL_ACTIVE);
  rfilter.matchvalue = (REL_INCLUDED | REL_ACTIVE);

  if (!slv_count_solvers_rels(server,&rfilter)) {
    return (FALSE);
  }

  for( rp=slv_get_solvers_rel_list(server); *rp != NULL ; ++rp ) {
    if( rel_less(*rp) || rel_greater(*rp) ) return(FALSE);
  }
  return(TRUE);
}

static
void slv4_get_parameters(slv_system_t server, SlvClientToken asys,
                         slv_parameters_t *parameters)
{
  slv4_system_t sys;
  (void) server;
  sys = SLV4(asys);
  if (check_system(sys)) return;
  mem_copy_cast(&(sys->p),parameters,sizeof(slv_parameters_t));
}

static void slv4_set_parameters(slv_system_t server, SlvClientToken asys,
                         slv_parameters_t *parameters)
{
  slv4_system_t sys;
  (void) server;
  sys = SLV4(asys);
  if (check_system(sys)) return;
  mem_copy_cast(parameters,&(sys->p),sizeof(slv_parameters_t));
}

static void slv4_get_status(slv_system_t server, SlvClientToken asys,
                            slv_status_t *status)
{
  slv4_system_t sys;
  (void) server;
  sys = SLV4(asys);
  if (check_system(sys)) return;
  mem_copy_cast(&(sys->s),status,sizeof(slv_status_t));
}

static linsolqr_system_t slv4_get_linsolqr_sys(slv_system_t server,
                                               SlvClientToken asys)
{
  slv4_system_t sys;
  (void) server;
  sys = SLV4(asys);
  if (check_system(sys)) return NULL;
  return(sys->J.sys);
}

static linsol_system_t slv4_get_linsol_sys(slv_system_t server,
                                           SlvClientToken asys)
{
  (void) server;
  (void) asys;
  return( NULL );
}

/*
 *  Performs structural analysis on the system, setting the flags in
 *  status.  The problem must be set up, the relation/variable list
 *  must be non-NULL.  The
 *  jacobian (linear) system must be created and have the correct order
 *  (stored in sys->cap).  Everything else will be determined here.
 *  On entry there isn't yet a correspondence between var_sindex and
 *  jacobian column. Here we establish that.
 */
static void structural_analysis(slv_system_t server, slv4_system_t sys)
{
  var_filter_t vfilter;
  rel_filter_t rfilter;

  /*
   * The server has marked incidence flags already.
   */
  /* count included equalities */
  rfilter.matchbits = (REL_INCLUDED | REL_EQUALITY | REL_ACTIVE);
  rfilter.matchvalue = (REL_INCLUDED | REL_EQUALITY | REL_ACTIVE);
  sys->rused = slv_count_solvers_rels(server,&rfilter);

  /* count free and incident vars */
  vfilter.matchbits = (VAR_FIXED | VAR_INCIDENT | VAR_SVAR | VAR_ACTIVE);
  vfilter.matchvalue = (VAR_INCIDENT | VAR_SVAR | VAR_ACTIVE);
  sys->vused = slv_count_solvers_vars(server,&vfilter);

  /* Symbolic analysis */
  sys->rtot = slv_get_num_solvers_rels(server);
  sys->vtot = slv_get_num_solvers_vars(server);
  if (sys->rtot) {
    slv_block_partition(server);
  }
  sys->J.dofdata = slv_get_dofdata(server);
  sys->rank = sys->J.dofdata->structural_rank;
 
  if( !(PARTITION) ) {
    /* maybe we should reorder blocks here? maybe not */
    slv_block_unify(server);
  }

  slv_check_bounds(SERVER,sys->vused,-1,"fixed ");

  /* Initialize Status */
  sys->s.over_defined = (sys->rused > sys->vused);
  sys->s.under_defined = (sys->rused < sys->vused);
  sys->s.struct_singular = (sys->rank < sys->rused);
  sys->s.block.number_of = (slv_get_solvers_blocks(SERVER))->nblocks;
}


static void set_factor_options (slv4_system_t sys)
{
  if (strcmp(FACTOR_OPTION,"SPK1/RANKI") == 0) {
    sys->J.fm = ranki_kw;
  } else if (strcmp(FACTOR_OPTION,"SPK1/RANKI+ROW") == 0) {
    sys->J.fm = ranki_jz;
  } else if (strcmp(FACTOR_OPTION,"Fast-SPK1/RANKI") == 0) {
    sys->J.fm = ranki_kw2;
  } else if (strcmp(FACTOR_OPTION,"Fast-SPK1/RANKI+ROW") == 0) {
    sys->J.fm = ranki_jz2;
  } else if (strcmp(FACTOR_OPTION,"Fastest-SPK1/MR-RANKI") == 0) {
    sys->J.fm = ranki_ba2;
/*  } else if (strcmp(FACTOR_OPTION,"GAUSS") == 0) {
    sys->J.fm = gauss_ba2;
  } else if (strcmp(FACTOR_OPTION,"GAUSS_EASY") == 0) {
    sys->J.fm = gauss_easy;
  } else if (strcmp(FACTOR_OPTION,"NGSLV-2-LEVEL") == 0) {
    sys->J.fm = ranki_kt2;*/
  } else {
    sys->J.fm = ranki_ba2;
  }
  mtx_set_order(sys->J.mtx,sys->cap);

  linsolqr_set_matrix(sys->J.sys,sys->J.mtx);
  linsolqr_prep(sys->J.sys,linsolqr_fmethod_to_fclass(sys->J.fm));
  linsolqr_set_pivot_zero(sys->J.sys, SING_TOL);

  /* KHACK NOTE: looks like drop tol never set on interface */
  linsolqr_set_drop_tolerance(sys->J.sys, sys->p.tolerance.drop);
  linsolqr_set_pivot_tolerance(sys->J.sys, PIVOT_TOL);
  /* this next one is fishy, but we don't use qr so not panicking */
  linsolqr_set_condition_tolerance(sys->J.sys, PIVOT_TOL);
}


/*
  configures linsolqr system, among other things.
  sets type to be ranki_kw or ranki_jz as determined by
  parameters.
*/
static void create_matrices(slv_system_t server, slv4_system_t sys)
{
  sys->J.sys = linsolqr_create();
  sys->J.mtx = mtx_create();

  set_factor_options(sys);

  /* rhs 0 for sys->newton */
  sys->J.rhs = create_array(sys->cap,real64);
  linsolqr_add_rhs(sys->J.sys,sys->J.rhs,FALSE);
  structural_analysis(server,sys);

}

static void create_vectors(sys)
slv4_system_t sys;
{
  sys->nominals.vec = create_array(sys->cap,real64);
  sys->nominals.rng = &(sys->J.reg.col);
  sys->weights.vec = create_array(sys->cap,real64);
  sys->weights.rng = &(sys->J.reg.row);
  sys->relnoms.vec = create_array(sys->cap,real64);
  sys->relnoms.rng = &(sys->J.reg.row);
  sys->variables.vec = create_array(sys->cap,real64);
  sys->variables.rng = &(sys->J.reg.col);
  sys->residuals.vec = create_array(sys->cap,real64);
  sys->residuals.rng = &(sys->J.reg.row);
  sys->newton.vec = create_array(sys->cap,real64);
  sys->newton.rng = &(sys->J.reg.col);
  sys->gamma.vec = create_array(sys->cap,real64);
  sys->gamma.rng = &(sys->J.reg.col);
  sys->Jgamma.vec = create_array(sys->cap,real64);
  sys->Jgamma.rng = &(sys->J.reg.row);
  sys->varstep1.vec = create_array(sys->cap,real64);
  sys->varstep1.rng = &(sys->J.reg.col);
  sys->varstep2.vec = create_array(sys->cap,real64);
  sys->varstep2.rng = &(sys->J.reg.col);
  sys->varstep.vec = create_array(sys->cap,real64);
  sys->varstep.rng = &(sys->J.reg.col);

}

static
void slv4_dump_internals(slv_system_t server, SlvClientToken sys,int level)
{
  (void) server;
  check_system(sys);
  if (level > 0) {
    FPRINTF(stderr,"ERROR:  (slv4) slv4_dump_internals\n");
    FPRINTF(stderr,"        slv4 does not dump its internals.\n");
  }
}

/*
 * Here we will check if any fixed or included flags have
 * changed since the last presolve.
 */
static
int32 slv4_dof_changed(slv4_system_t sys)
{
  int32 ind, result = 0;
  /* Currently we have two copies of the fixed and included flags
     which must be kept in sync.  The var_fixed and rel_included
     functions perform the syncronization and hence must be called
     over the whole var list and rel list respectively.  When we move
     to using only one set of flags (bit flags) this function can
     be changed to return 1 at the first indication of a change
     in the dof. */

  /* search for vars that were fixed and are now free */
  for( ind = sys->vused; ind < sys->vtot; ++ind ) {
    if( !var_fixed(sys->vlist[ind]) && var_active(sys->vlist[ind]) ) {
      ++result;
    }
  }
  /* search for rels that were unincluded and are now included */
  for( ind = sys->rused; ind < sys->rtot; ++ind ) {
    if( rel_included(sys->rlist[ind]) && rel_active(sys->rlist[ind])) {
      ++result;
    }
  }
  /* search for vars that were free and are now fixed */
  for( ind = sys->vused -1; ind >= 0; --ind ) {
    if( var_fixed(sys->vlist[ind]) ||  !var_active(sys->vlist[ind])) {
      ++result;
    }
  }
  /* search for rels that were included and are now unincluded */
  for( ind = sys->rused -1; ind >= 0; --ind ) {
    if( !rel_included(sys->rlist[ind]) || !rel_active(sys->rlist[ind]) ) {
      ++result;
    }
  }
  return result;
}


static void reset_cost(struct slv_block_cost *cost,int32 costsize)
{
  int32 ind;
  for( ind = 0; ind < costsize; ++ind ) {
    cost[ind].size = 0;
    cost[ind].iterations = 0;
    cost[ind].funcs = 0;
    cost[ind].jacs = 0;
    cost[ind].functime = 0;
    cost[ind].jactime = 0;
    cost[ind].time = 0;
    cost[ind].resid = 0;
  }
}

static void slv4_update_linsolqr(slv4_system_t sys)
{
  if (strcmp(FACTOR_OPTION,"SPK1/RANKI") == 0) {
    sys->J.fm = ranki_kw;
  } else if (strcmp(FACTOR_OPTION,"SPK1/RANKI+ROW") == 0) {
    sys->J.fm = ranki_jz;
  } else if (strcmp(FACTOR_OPTION,"Fast-SPK1/RANKI") == 0) {
    sys->J.fm = ranki_kw2;
  } else if (strcmp(FACTOR_OPTION,"Fast-SPK1/RANKI+ROW") == 0) {
    sys->J.fm = ranki_jz2;
  } else if (strcmp(FACTOR_OPTION,"Fastest-SPK1/MR-RANKI") == 0) {
    sys->J.fm = ranki_ba2;
/*  } else if (strcmp(FACTOR_OPTION,"GAUSS_EASY") == 0) {
    sys->J.fm = gauss_easy;
  } else if (strcmp(FACTOR_OPTION,"NGSLV-2-LEVEL") == 0) {
    sys->J.fm = ranki_kt2;*/
  } else {
    sys->J.fm = ranki_ba2;
  }
  linsolqr_set_pivot_zero(sys->J.sys, SING_TOL);
  linsolqr_set_drop_tolerance(sys->J.sys, sys->p.tolerance.drop);
  linsolqr_set_pivot_tolerance(sys->J.sys, PIVOT_TOL);
  /* this next one is fishy, but we don't use qr so not panicking */
  linsolqr_set_condition_tolerance(sys->J.sys, PIVOT_TOL);
}

static
void slv4_presolve(slv_system_t server, SlvClientToken asys)
{
  struct var_variable **vp;
  struct rel_relation **rp;
  int32 cap, ind;
  int32 matrix_creation_needed = 1;
  slv4_system_t sys;

  sys = SLV4(asys);
  iteration_begins(sys);
  check_system(sys);
  if( sys->vlist == NULL ) {
    FPRINTF(stderr,"ERROR:  (slv4) slv4_presolve\n");
    FPRINTF(stderr,"        Variable list was never set.\n");
    return;
  }
  if( sys->rlist == NULL && sys->obj == NULL ) {
    FPRINTF(stderr,"ERROR:  (slv4) slv4_presolve\n");
    FPRINTF(stderr,"        Relation list and objective never set.\n");
    return;
  }

  if(sys->presolved > 0) { /* system has been presolved before */
    if(!slv4_dof_changed(sys) /* no changes in fixed or included flags */
       && PARTITION == sys->J.old_partition) {
#if DEBUG
      FPRINTF(stderr,"YOU JUST AVOIDED MATRIX DESTRUCTION/CREATION\n");
#endif
      matrix_creation_needed = 0;
    }
  }

  rp=sys->rlist;
  for( ind = 0; ind < sys->rtot; ++ind ) {
    rel_set_satisfied(rp[ind],FALSE);
  }
  if( matrix_creation_needed ) {

    cap = slv_get_num_solvers_rels(SERVER);
    sys->cap = slv_get_num_solvers_vars(SERVER);
    sys->cap = MAX(sys->cap,cap);
    vp=sys->vlist;
    for( ind = 0; ind < sys->vtot; ++ind ) {
      var_set_in_block(vp[ind],FALSE);
    }
    rp=sys->rlist;
    for( ind = 0; ind < sys->rtot; ++ind ) {
      rel_set_in_block(rp[ind],FALSE);
      rel_set_satisfied(rp[ind],FALSE);
    }

    sys->presolved = 1; /* full presolve recognized here */
    sys->J.old_partition = PARTITION;
    destroy_matrices(sys);
    destroy_vectors(sys);
    create_matrices(server,sys);
    create_vectors(sys);

    sys->s.block.current_reordered_block = -2;
  } else {
    slv4_update_linsolqr(sys);
  }

  /* Reset status */
  sys->s.iteration = 0;
  sys->s.cpu_elapsed = 0.0;
  sys->s.converged = sys->s.diverged = sys->s.inconsistent = FALSE;
  sys->s.block.previous_total_size = 0;
  sys->s.costsize = 1+sys->s.block.number_of;

  if( matrix_creation_needed ) {
    destroy_array(sys->s.cost);
    sys->s.cost = create_zero_array(sys->s.costsize,struct slv_block_cost);
    for( ind = 0; ind < sys->s.costsize; ++ind ) {
      sys->s.cost[ind].reorder_method = -1;
    }
  } else {
    reset_cost(sys->s.cost,sys->s.costsize);
  }

  /* set to go to first unconverged block */
  sys->s.block.current_block = -1;
  sys->s.block.current_size = 0;
  sys->s.calc_ok = TRUE;
  sys->s.block.iteration = 0;
  sys->objective =  MAXDOUBLE/2000.0;

  update_status(sys);
  iteration_ends(sys);
  sys->s.cost[sys->s.block.number_of].time=sys->s.cpu_elapsed;
}


static void slv4_resolve(slv_system_t server, SlvClientToken asys)
{
  struct var_variable **vp;
  struct rel_relation **rp;
  slv4_system_t sys;
  (void) server;
  sys = SLV4(asys);

  check_system(sys);
  for( vp = sys->vlist ; *vp != NULL ; ++vp ) {
    var_set_in_block(*vp,FALSE);
  }
  for( rp = sys->rlist ; *rp != NULL ; ++rp ) {
    rel_set_in_block(*rp,FALSE);
    rel_set_satisfied(*rp,FALSE);
  }

  /* Reset status */
  sys->s.iteration = 0;
  sys->s.cpu_elapsed = 0.0;
  sys->s.converged = sys->s.diverged = sys->s.inconsistent = FALSE;
  sys->s.block.previous_total_size = 0;

  /* go to first unconverged block */
  sys->s.block.current_block = -1;
  sys->s.block.current_size = 0;
  sys->s.calc_ok = TRUE;
  sys->s.block.iteration = 0;
  sys->objective =  MAXDOUBLE/2000.0;

  update_status(sys);
}


static void slv4_iterate(slv_system_t server, SlvClientToken asys)
{
  slv4_system_t sys;
  FILE              *mif;
  FILE              *lif;
  real64            bounds_coef=1.0;
  real64            previous = 0.0;
  real64            oldphi;
  boolean           first=TRUE, bounds_ok=FALSE,
                    new_ok=FALSE, descent_ok=FALSE;
  int               minor = 0,ds_status