/*
 *  IPSlv ASCEND Interior Point Method Solver
 *  by Vicente Rico-Ramirez based on QRSlv
 *  Created: 
 *  Version: $ $
 *  Version control file: $ $
 *  Date last modified: $ $
 *  Last modified by: $Author: $
 *
 *  This file is part of the SLV solver.
 *
 *  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/slv5.h"
#include "solver/slv_stdcalls.h"

#if !defined(STATIC_IPSLV) && !defined(DYNAMIC_IPSLV)
int slv5_register(SlvFunctionsT *f)
{
  (void)f;  /* stop gcc whine about unused parameter */

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

#define DEBUG TRUE
#define DEBUG_COMPLEMENTARY_VAR TRUE
#define DEBUG_OBJ_VALUES TRUE
#define DEBUG_ITERATION TRUE
#define DEBUG_CENTERING TRUE

#define SLV5(s) ((slv5_system_t)(s))
#define SERVER (sys->slv)
#define slv5_PA_SIZE 27 /* MUST INCREMENT WHEN ADDING PARAMETERS */
#define slv5_RA_SIZE 4

/* do not delete (or extend) this array definition.
*/
#define IEX(n) slv5_iaexpln[(n)]
#define slv5_IA_SIZE 10
static char *slv5_iaexpln[slv5_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",
"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",
"Check jacobian for poorly scaled columns and whine if found",
"Reorder option. 0 = MODEL based, 1 = MODEL based2, 2 = simple spk1",
"Use safe calculation routines",
"scaleopt = 0: 2norm"
};

/* change  slv5_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 DUMPCNORM_PTR		(sys->parm_array[3])
#define DUMPCNORM		((*(int *)DUMPCNORM_PTR))
#define SAFE_CALC_PTR		(sys->parm_array[4])
#define SAFE_CALC		((*(int *)SAFE_CALC_PTR))
#define SCALEOPT_PTR		(sys->parm_array[5])
#define SCALEOPT		((*(char **)SCALEOPT_PTR))
#define TOO_SMALL_PTR		(sys->parm_array[6])
#define TOO_SMALL		((*(real64 *)TOO_SMALL_PTR))
#define CNLOW_PTR		(sys->parm_array[7])
#define CNLOW			((*(real64 *)CNLOW_PTR))
#define CNHIGH_PTR		(sys->parm_array[8])
#define CNHIGH			((*(real64 *)CNHIGH_PTR))
#define TOWARD_BOUNDS_PTR	(sys->parm_array[9])
#define TOWARD_BOUNDS		((*(real64 *)TOWARD_BOUNDS_PTR))
#define IGNORE_BOUNDS_PTR	(sys->parm_array[10])
#define IGNORE_BOUNDS		((*(int32 *)IGNORE_BOUNDS_PTR))
#define RHO_PTR			(sys->parm_array[11])
#define RHO			((*(real64 *)RHO_PTR))
#define PARTITION_PTR		(sys->parm_array[12])
#define PARTITION		((*(int32 *)PARTITION_PTR))
#define SHOW_LESS_IMPT_PTR	(sys->parm_array[13])
#define SHOW_LESS_IMPT		((*(int32 *)SHOW_LESS_IMPT_PTR))
#define TIME_LIMIT_PTR		(sys->parm_array[14])
#define TIME_LIMIT		((*(int32 *)TIME_LIMIT_PTR))
#define ITER_LIMIT_PTR		(sys->parm_array[15])
#define ITER_LIMIT		((*(int32 *)ITER_LIMIT_PTR))
#define ALPHA_PTR		(sys->parm_array[16])
#define ALPHA   		((*(real64 *)ALPHA_PTR))
#define SING_TOL_PTR		(sys->parm_array[17])
#define SING_TOL		((*(real64 *)SING_TOL_PTR))
#define PIVOT_TOL_PTR		(sys->parm_array[18])
#define PIVOT_TOL		((*(real64 *)PIVOT_TOL_PTR))
#define FEAS_TOL_PTR		(sys->parm_array[19])
#define FEAS_TOL		((*(real64 *)FEAS_TOL_PTR))
#define LIFDS_PTR		(sys->parm_array[20])
#define LIFDS			((*(int32 *)LIFDS_PTR))
#define SAVLIN_PTR		(sys->parm_array[21])
#define SAVLIN			((*(int32 *)SAVLIN_PTR))
#define REORDER_OPTION_PTR	(sys->parm_array[22])
#define REORDER_OPTION		((*(char **)REORDER_OPTION_PTR))
#define CUTOFF_PTR		(sys->parm_array[23])
#define CUTOFF			((*(int32 *)CUTOFF_PTR))
#define FACTOR_OPTION_PTR	(sys->parm_array[24])
#define FACTOR_OPTION		((*(char **)FACTOR_OPTION_PTR))
#define CONVOPT_PTR		(sys->parm_array[25])
#define CONVOPT			((*(char **)CONVOPT_PTR))
#define LINTIME_PTR		(sys->parm_array[26])
#define LINTIME			((*(int *)LINTIME_PTR))
/* change  slv5_PA_SIZE above (MUST INCREMENT) WHEN ADDING PARAMETERS */


#define REX(n) slv5_raexpln[(n)]
static
char *slv5_raexpln[slv5_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"};

struct update_data {
  int                    jacobian;   /* Countdown on jacobian updating */
  int                    weights;    /* Countdown on weights updating */
  int                    nominals;   /* Countdown on nominals updating */
};


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 slv5_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[slv5_PA_SIZE];      /* array of pointers to param values */
  struct slv_parameter pa[slv5_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     variables;    /* Variable values */
  struct vector_data     residuals;    /* Relation residuals */
  struct vector_data     newton_residuals;  /* Newton Relation residuals */
  struct vector_data     perturbed_residuals;/* Perturbed Relation residuals */
  struct vector_data     newton;       /* Dependent variables */
  struct vector_data     perturbed_newton;  /* Perturbed Newton direction */
  struct vector_data     varnewstep;/* hypothetical newton step in variables */
  struct vector_data     varstep;      /* Step in variables */

  real64                 progress;     /* expected progress */
  real64                 sigma;        /* penalty parameter */
  real64                 mu;           /* Complementary gap */
  real64                 muaff;        /* Complementary gap after newton */
  real64                 sigmamu;      /* Complementary gap times penalty */
  real64                 eta;          /* penalty of objective */
  real64                 nu;           /* objective residuals */
  real64                 psi;          /* Objective */
  real64                 comp;         /* no. of complementary eqns.  */
};


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

#define OK        ((int)813029392)
#define DESTROYED ((int)103289182)
static int check_system(slv5_system_t sys)
/*
 *  Checks sys for NULL and for integrity.
 */
{
  if( sys == NULL ) {
    FPRINTF(ASCERR,"ERROR:  (slv5) check_system\n");
    FPRINTF(ASCERR,"        NULL system handle.\n");
    return 1;
  }

  switch( sys->integrity ) {
  case OK:
    return 0;
  case DESTROYED:
    FPRINTF(ASCERR,"ERROR:  (slv5) check_system\n");
    FPRINTF(ASCERR,"        System was recently destroyed.\n");
    return 1;
  default:
    FPRINTF(ASCERR,"ERROR:  (slv5) check_system\n");
    FPRINTF(ASCERR,"        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, 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, slv5_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, slv5_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, slv5_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
 *  --------------------
 *     calc_eta(server)
 *     ok = calc_residuals(sys)
 *     ok = calc_mu(sys)
 *     ok = calc_newton_residuals(sys)
 *     ok = calc_muaff(sys)
 *     ok = calc_sigma(sys)
 *     ok = calc_sigmamu(sys)
 *     ok = calc_perturbed_residuals(sys)
 *     ok = calc_J(sys)
 *     calc_nominals(sys)
 *     calc_weights(sys)
 *     scale_J(sys)
 *     scale_variables(sys)
 *     scale_residuals(sys)
 *     scale_perturbed_residuals(sys)
 *     calc_pivots(sys)
 *     calc_rhs(sys)
 *     calc_newton(sys)
 *     calc_perturbed_newton(sys)
 *     calc_varnewstep(sys)
 *     calc_varstep(sys)
 *     calc_nu(sys)
 *     calc_psi(sys)
 */


/*
 *  Calculates the penalty of objective function
 */
static void calc_comp( slv5_system_t sys )
{
  int32 row;
  struct rel_relation *rel;
  real64 comp;

  comp = 0.0;
  row = sys->residuals.rng->low;
  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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_comp\n",(int)row,r);
      FFLUSH(ASCERR);
    }
#endif
    if (rel_active(rel) && rel_included (rel) && rel_complementary(rel)) {  
#if DEBUG
      FPRINTF(ASCERR,"Complementary equation in slv5 \n");
#endif /* DEBUG */
      comp = comp + 1.0; 
    }
  }
 
#if DEBUG_ITERATION
  FPRINTF(ASCERR," No. of complementary eqns = %g \n",comp);
#endif /*  DEBUG_ITERATION  */
  sys->comp = comp;
}

/*
 *  Calculates the penalty of objective function
 */
static void calc_eta( slv5_system_t sys)
{

  real64 eta;

  if (sys->comp == 0.0) {
    eta = 0.0;
  } else {
    eta =  sys->comp * sqrt(sys->comp);
  }
#if DEBUG_ITERATION
  FPRINTF(ASCERR," eta = %g \n",eta);
#endif /*  DEBUG_ITERATION  */
  sys->eta = eta;
}


/*
 *  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( slv5_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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_residuals\n",(int)row,r);
      FFLUSH(ASCERR);
    }
#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 complementary gap in the current point
 */
static boolean calc_mu( slv5_system_t sys)
{

  int32 row;
  struct rel_relation *rel;
  real64 muk;

  muk = 0.0;
  row = sys->residuals.rng->low;

#if DEBUG_CENTERING
  FPRINTF(ASCERR,"row low is = %d \n",row);
  FPRINTF(ASCERR,"row high is = %d \n",sys->residuals.rng->high);
#endif /* DEBUG_CENTERING */

  for(row ; 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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_mu \n",(int)row,r);
      FFLUSH(ASCERR);
    }
#endif
    if (rel_complementary(rel) && rel_active(rel)  && rel_included(rel)) { 
      muk = muk + rel_residual(rel);
#if DEBUG
      FPRINTF(ASCERR,"Complementary equation in calc_mu \n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",sys->residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
      FPRINTF(ASCERR,"Partial muk is = %g \n",muk);
#endif /* DEBUG */ 
    }
  }

  if (sys->comp > 0.0) {
    muk = muk / sys->comp;
  } else {
    muk = 0.0;
  }

  sys->mu = muk;

#if DEBUG_CENTERING
  FPRINTF(ASCERR,"muk is = %g \n",sys->mu);
#endif /* DEBUG_CENTERING */

  return(calc_ok);
}


/*
 *  Calculates all of the residuals in the current block and computes
 *  the residual norm for block status after a hypothetical Newton
 *  step.  Returns true iff calculations
 *  preceded without error.
 */
static boolean calc_newton_residuals( slv5_system_t sys)
{
  int32 row;
  struct rel_relation *rel;

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

  calc_ok = TRUE;
  row = sys->newton_residuals.rng->low;
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  for( ; row <= sys->newton_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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_newton_residuals\n",(int)row,r);
      FFLUSH(ASCERR);
    }
#endif
    sys->newton_residuals.vec[row] = relman_eval(rel,&calc_ok,SAFE_CALC);
  }
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  square_norm( &(sys->newton_residuals) );
  return(calc_ok);
}

/*
 *  Calculates the complementary gap after a hypothetical Newton Step
 */
static boolean calc_muaff( slv5_system_t sys)
{
  int32 row;
  struct rel_relation *rel;
  real64 muaff;

  muaff = 0.0;
  row = sys->newton_residuals.rng->low;
  for(row ; row <= sys->newton_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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_muaff\n",(int)row,r);
      FFLUSH(ASCERR);
    }
#endif
    if (rel_complementary(rel) && rel_active(rel)  && rel_included(rel)) { 
      muaff = muaff + sys->newton_residuals.vec[row];
 #if DEBUG
      FPRINTF(ASCERR,"Complementary equation in calc_muaff \n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",sys->newton_residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
      FPRINTF(ASCERR,"Partial muaff is = %g \n",muaff);
#endif /* DEBUG */ 
    }
  }

  if (sys->comp > 0.0) {
    muaff = muaff / sys->comp;
  } else {
    muaff = 0.0;
  }

  sys->muaff = muaff;

#if DEBUG_CENTERING
  FPRINTF(ASCERR,"muaff is = %g \n",sys->muaff);
#endif /* DEBUG_CENTERING */

  return(calc_ok);
}


/*
 *  Calculates the penalty parameter sigma
 */
static boolean calc_sigma( slv5_system_t sys)
{
  real64 sigma, frac;

  if ((sys->mu) > 0.0) {
    frac = (sys->muaff) / (sys->mu);
    sigma = (frac) * (frac) * (frac);
  } else {
    frac = 0.0;
    sigma = 0.0;
  }

  sys->sigma = sigma;

#if DEBUG_CENTERING
  FPRINTF(ASCERR,"sigma is = %g \n",sys->sigma);
#endif /* DEBUG_CENTERING */

  return(calc_ok); 
}

/*
 *  Calculates the penalty parameter time the complementary gap
 */
static boolean calc_sigmamu( slv5_system_t sys)
{
  real64 sigmamu;

  if ((sys->mu) > 0.0 && (sys->sigma) > 0.0) {
    sigmamu = (sys->mu) * (sys->sigma);
  } else {
    sigmamu = 0.0;
  }

  sys->sigmamu = sigmamu;

#if DEBUG_CENTERING
  FPRINTF(ASCERR,"sigma mu is = %g \n",sys->sigmamu);
#endif /* DEBUG_CENTERING */

  return(calc_ok);
}


/*
 *  Calculates the perturbed residuals in the current block and computes
 *  the perturbed residual norm. Returns true iff calculations
 *  preceded without error.
 */
static boolean calc_perturbed_residuals( slv5_system_t sys)
{
  int32 row;
  struct rel_relation *rel;

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

  calc_ok = TRUE;
  row = sys->perturbed_residuals.rng->low;
  Asc_SignalHandlerPush(SIGFPE,SIG_IGN);
  for( ; row <= sys->perturbed_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(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_perturbed _residuals\n",
             (int)row,r);
      FFLUSH(ASCERR);
    }
#endif
    sys->perturbed_residuals.vec[row] = relman_eval(rel,&calc_ok,SAFE_CALC);
#if DEBUG
    FPRINTF(ASCERR,"calc_perturbed_residuals \n");
    FPRINTF(ASCERR,"row = %d\n",row);
    FPRINTF(ASCERR,"residual vector = %g\n",
	    sys->perturbed_residuals.vec[row]);
    FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
#endif /* DEBUG */ 
    if (rel_complementary(rel) && rel_active(rel)  && rel_included(rel)) {  
      sys->perturbed_residuals.vec[row] = sys->perturbed_residuals.vec[row] -
	                                  sys->sigmamu ;
#if DEBUG
      FPRINTF(ASCERR,"residual vector - sigmamu = %g\n",
	      sys->perturbed_residuals.vec[row]);
#endif /* DEBUG */ 
    }
  }
  Asc_SignalHandlerPop(SIGFPE,SIG_IGN);
  square_norm( &(sys->perturbed_residuals) );
  return(calc_ok);
}

/*
 *  Calculates the current block of the jacobian.
 *  It is initially unscaled.
 */
static boolean calc_J( slv5_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( slv5_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){
    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:  (slv5) 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:  (slv5) 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 ",col);
      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( slv5_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) {
    for( ; nz.row <= sys->weights.rng->high; (nz.row)++ ) {
      sys->weights.vec[nz.row] = 1;
    }
  } else if (strcmp(SCALEOPT,"ROW_2NORM") == 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;
    }
  }
  square_norm( &(sys->weights) );
  sys->update.weights = UPDATE_WEIGHTS;
  sys->residuals.accurate = FALSE;
  sys->weights.accurate = TRUE;
}

/*
 *  Scales the jacobian.
 */
static void scale_J( slv5_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(slv5_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(ASCERR,"[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( slv5_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->variables));
#endif
}

/*
 *  Scales the previously calculated residuals.
 */
static void scale_residuals( slv5_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->residuals));
#endif
}

/*
 *  Scales the previously calculated residuals.
 */
static void scale_perturbed_residuals( slv5_system_t sys)
{
  int32 row;

  if( sys->perturbed_residuals.accurate ) return;

  row = sys->perturbed_residuals.rng->low;
  for( ; row <= sys->perturbed_residuals.rng->high; row++ ) {
    struct rel_relation *rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
 #if DEBUG
      FPRINTF(ASCERR,"scale_perturbed_residuals \n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",
	      sys->perturbed_residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
#endif /* DEBUG */ 
    sys->perturbed_residuals.vec[row] = sys->perturbed_residuals.vec[row]
                                        * sys->weights.vec[row];
  }
  square_norm( &(sys->perturbed_residuals) );
  sys->perturbed_residuals.accurate = TRUE;
#if DEBUG
  FPRINTF(LIF(sys),"Perturbed Residuals:  ");
  debug_out_vector(LIF(sys),&(sys->perturbed_residuals));
#endif
}


/*
 * Scale system dependent on interface parameters
 */
static void scale_perturbed_system( slv5_system_t sys )
{
  if(strcmp(SCALEOPT,"NONE") == 0){
    scale_perturbed_residuals(sys);
    return;
  }
  if(strcmp(SCALEOPT,"ROW_2NORM") == 0){
    scale_perturbed_residuals(sys);
    return;
  }
}

/*
 * Scale system dependent on interface parameters
 */
static void scale_system( slv5_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 ){
    if(sys->J.accurate == FALSE){
      scale_J(sys);
      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(slv5_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;
        sys->perturbed_residuals.vec[row] = 0.0;
        sys->perturbed_residuals.accurate = FALSE;
        sys->newton_residuals.vec[row] = 0.0;
        sys->newton_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(slv5_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);
}

/*
 *  Computes a step to solve the linearized equations.
 */
static void calc_newton( slv5_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->newton));
#endif
}

/*
 *  Computes a step to solve the linearized equations.
 */
static void calc_perturbed_newton( slv5_system_t sys)
{
   linsolqr_system_t lsys = sys->J.sys;
   int32 col;

   if( sys->perturbed_newton.accurate )
      return;

   sys->J.rhs = linsolqr_get_rhs(lsys,1);
   mtx_zero_real64(sys->J.rhs,sys->cap);
   calc_rhs(sys, &(sys->perturbed_residuals), -1.0, FALSE);
   linsolqr_solve(lsys,sys->J.rhs);
   col = sys->perturbed_newton.rng->low;
   for( ; col <= sys->perturbed_newton.rng->high; col++ ) {
     sys->perturbed_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->perturbed_newton) );
   sys->perturbed_newton.accurate = TRUE;
#if DEBUG
   FPRINTF(LIF(sys),"Perturbed Newton:  ");
   debug_out_vector(LIF(sys),&(sys->perturbed_newton));
#endif
}



/*
 *  Calculate the perturbed descent direction
 *  in the variables.
 */
static void calc_varstep( slv5_system_t sys)
{
   if( sys->varstep.accurate )
      return;
      copy_vector(&(sys->perturbed_newton),&(sys->varstep));
      sys->varstep.norm2 = sys->perturbed_newton.norm2;

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

/*
 *  Calculate the hypothetical netown direction
 *  in the variables.
 */
static void calc_varnewstep( slv5_system_t sys)
{
   if( sys->varnewstep.accurate )
      return;
      copy_vector(&(sys->newton),&(sys->varnewstep));
      sys->varnewstep.norm2 = sys->newton.norm2;

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

/*
 *  Computes the error nu.
 */
static void calc_nu( slv5_system_t sys)
{
  struct rel_relation *rel;
  int32 row, r;
  real64 error;

  error = 0.0;
  row = sys->residuals.rng->low;
  for(row = sys->residuals.rng->low; row <= sys->residuals.rng->high; row++) {
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
    if (!rel) {
      r=mtx_row_to_org(sys->J.mtx,row);
      FPRINTF(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_nu\n",(int)row,r);
      FFLUSH(ASCERR);
    }
    if (rel_complementary(rel) && rel_active(rel) && rel_included(rel)) {
 #if DEBUG
      FPRINTF(ASCERR,"Complementary equation in calc_nu \n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",sys->residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
#endif /* DEBUG */ 
        error = error + rel_residual(rel);
    } else {
      if (rel_active(rel) && rel_included(rel)) {
        error = error + (rel_residual(rel) *rel_residual(rel) );
#if DEBUG
      FPRINTF(ASCERR,"Non complementary equation calc_nu \n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",sys->residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
#endif /* DEBUG */ 
      }
    }
  }

  sys->nu = error;

#if DEBUG_OBJ_VALUES
  FPRINTF(ASCERR," Error nu  = %g \n",sys->nu);
#endif /*  DEBUG_OBJ_VALUES  */
}


/*
 *  Computes the objective function Psi.
 */
static void calc_psi( slv5_system_t sys)
{

  struct rel_relation *rel;
  int32 row, r;
  real64 sum, sumt;

  calc_nu( sys);

  sum = 0.0;
  for(row = sys->residuals.rng->low; row <= sys->residuals.rng->high; row++) {
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,row)];
    if (!rel) {
      r = mtx_row_to_org(sys->J.mtx,row);
      FPRINTF(ASCERR,"NULL relation found !!\n");
      FPRINTF(ASCERR,"at row %d rel %d in calc_psi\n",(int)row,r);
      FFLUSH(ASCERR);
    }
    if (rel_complementary(rel) && rel_active(rel) && rel_included(rel)) {
 #if DEBUG
      FPRINTF(ASCERR,"Complementary equation in calc_psi\n");
      FPRINTF(ASCERR,"row = %d\n",row);
      FPRINTF(ASCERR,"residual vector = %g\n",sys->residuals.vec[row]);
      FPRINTF(ASCERR,"rel_residual = %g \n",rel_residual(rel));
#endif /* DEBUG */ 
      sumt = log10(rel_residual(rel));
      sum = sum + sumt;
    }
  }

  if (sys->eta > 0.0) {
    sys->psi = ( sys->eta * log10(sys->nu) ) - sum;
  } else {
    sys->psi =  0.5*sys->residuals.norm2;
  }

#if DEBUG_OBJ_VALUES
  FPRINTF(ASCERR," Psi = %g \n",sys->psi);
#endif /*  DEBUG_OBJ_VALUES  */
}



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

/*
 *  Restores the values of the variables before applying
 *  a step.
 */
static void restore_variables( slv5_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( slv5_system_t sys, int32 v) 
{
   real64 factor, minfactor;
   struct var_variable *var;
   real64 dx,val,bnd;
   int32 col;
   struct vector_data step;
   real64 *vec;

   vec = (sys->nominals.vec);

   if (v == 1) {
     step = sys->varstep;
   } else {
     step = sys->varnewstep;    
   }

   minfactor = 1.0;
   factor = 1.0;
   for( col=step.rng->low; col <= step.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 = step.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 = %g \n",factor);
#endif /* DEBUG_COMPLEMENTARY_VAR */
	 }
         if( factor < minfactor ) {
           minfactor = factor;
	 }
       }
     }
   }
#if DEBUG_COMPLEMENTARY_VAR
  FPRINTF(ASCERR,"Minimum complementary factor = %g \n",minfactor); 
#endif /* DEBUG_COMPLEMENTARY_VAR */
  return minfactor;
}


/*
 *  Adds  step to the variable values in block. It projects
 *  non complementary varaibles near bounds.
 */
static void apply_step( slv5_system_t sys, int32 v, real64 factor)
{
   FILE *lif = LIF(sys);
   struct var_variable *var;
   real64 dx,val,bnd;
   real64 bounds_coef;
   struct vector_data step;
   int32 col;
   real64 *vec;

   vec = (sys->nominals.vec);
   bounds_coef = 1.0;

   if (v == 1) {
     step = sys->varstep;
   } else {
     step = sys->varnewstep;    
   }

   for(col=step.rng->low; col<=step.rng->high;col++) {
     var = sys->vlist[mtx_col_to_org(sys->J.mtx,col)];
     dx = vec[col]*step.vec[col];
     val = var_value(var);
     dx = dx*factor;
     if( val + dx > (bnd=var_upper_bound(var)) ) {
       dx = TOWARD_BOUNDS*(bnd-val);
       if (SHOW_LESS_IMPT) {
         FPRINTF(lif,"%-40s ---> ",
                "    Variable projected to upper bound");
         print_var_name(lif,sys,var); PUTC('\n',lif);
       }
     } else if( val + dx < (bnd=var_lower_bound(var)) ) {
       dx = TOWARD_BOUNDS*(bnd-val);
       if (SHOW_LESS_IMPT) {
         FPRINTF(lif,"%-40s ---> ",
                 "    Variable projected to lower bound");
         print_var_name(lif,sys,var); PUTC('\n',lif);
       }
     }
      var_set_value(var,val+dx);
   }

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

   return;
}


/*
 *  This function should be called when the step is accepted.
 */
static void step_accepted( slv5_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_residuals.accurate = FALSE;
   sys->perturbed_residuals.accurate = FALSE;
   sys->newton.accurate = FALSE;
   sys->perturbed_newton.accurate = FALSE;
   sys->varnewstep.accurate = FALSE;
   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( slv5_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( slv5_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 (!(sys->p.ignore_bounds) ) {
      slv_insure_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");
    }

    /*
     * Update number of complementary equations
     */
    calc_comp(sys);
    calc_eta(sys);

    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->variables.accurate = FALSE;
    sys->newton_residuals.accurate = FALSE;
    sys->perturbed_residuals.accurate = FALSE;
    sys->newton.accurate = FALSE;
    sys->perturbed_newton.accurate = FALSE;
    sys->varnewstep.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;
    }
  }
}


/*
 *  Calls the appropriate reorder function on a block
 */
static void reorder_new_block(slv5_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(ASCERR,"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),"IPSlv called with unknown reorder option\n");
      FPRINTF(MIF(sys),"IPSlv 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( slv5_system_t sys)
{
   do {
     move_to_next_block(sys);
#if DEBUG
     debug_out_var_values(ASCERR,sys);
     debug_out_rel_residuals(ASCERR,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( slv5_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( slv5_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( slv5_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 slv5_get_default_parameters(slv_system_t server, SlvClientToken asys,
				  slv_parameters_t *parameters)
{
  slv5_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"
  };

  if (server != NULL && asys != NULL) {
    sys = SLV5(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 slv5_system_structure has this pointer
     * already set in slv5_create
     */
    new_parms = (struct slv_parameter *)
      ascmalloc((slv5_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, real_parm,
	       "rho", "search parameter", "search parameter",
	       U_p_real(val,0.5),U_p_real(lo, 0),U_p_real(hi,1.0), 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, 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,
	       "alpha","search coefficient" ,"search coefficient" ,
	       U_p_real(val,0.5),U_p_real(lo,0),U_p_real(hi,1.0), 1);
  SLV_RPARM_MACRO(ALPHA_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(8),
	       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, int_parm,
	       "cutoff", "block size cutoff (MODEL-based)", IEX(2),
	       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(3),
	       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(4),
	       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(5),
	       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, 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(9),
	       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,
	       "cncols", "Check poorly scaled columns", IEX(6),
	       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, char_parm,
	       "reorder", "reorder method", IEX(7),
	       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, 0.995),U_p_real(lo, 0),U_p_real(hi,1.0), 3);
  SLV_RPARM_MACRO(TOWARD_BOUNDS_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);

  return 1;
}

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

static SlvClientToken slv5_create(slv_system_t server, int *statusindex)
{
  slv5_system_t sys;

  sys = (slv5_system_t)asccalloc(1, sizeof(struct slv5_system_structure) );
  if (sys==NULL) {
    *statusindex = 1;
    return sys;
  }
  SERVER = server;
  sys->p.parms = sys->pa;
  sys->p.dynamic_parms = 0;
  slv5_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(ASCERR,"IPSlv called with no variables.\n");
    *statusindex = -2;
    return NULL; /*_prolly leak here */
  }
  if (sys->rlist == NULL && sys->obj == NULL) {
    ascfree(sys);
    FPRINTF(ASCERR,"IPSlv 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( slv5_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( slv5_system_t sys)
{
   destroy_array(sys->nominals.vec);
   destroy_array(sys->weights.vec);
   destroy_array(sys->variables.vec);
   destroy_array(sys->residuals.vec);
   destroy_array(sys->newton_residuals.vec);
   destroy_array(sys->perturbed_residuals.vec);
   destroy_array(sys->newton.vec);
   destroy_array(sys->perturbed_newton.vec);
   destroy_array(sys->varnewstep.vec);
   destroy_array(sys->varstep.vec);
}

static int slv5_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 slv5_get_parameters(slv_system_t server, SlvClientToken asys,
                         slv_parameters_t *parameters)
{
  slv5_system_t sys;
  (void) server;
  sys = SLV5(asys);
  if (check_system(sys)) return;
  mem_copy_cast(&(sys->p),parameters,sizeof(slv_parameters_t));
}

static void slv5_set_parameters(slv_system_t server, SlvClientToken asys,
                         slv_parameters_t *parameters)
{
  slv5_system_t sys;
  (void) server;
  sys = SLV5(asys);
  if (check_system(sys)) return;
  mem_copy_cast(parameters,&(sys->p),sizeof(slv_parameters_t));
}

static void slv5_get_status(slv_system_t server, SlvClientToken asys,
                            slv_status_t *status)
{
  slv5_system_t sys;
  (void) server;
  sys = SLV5(asys);
  if (check_system(sys)) return;
  mem_copy_cast(&(sys->s),status,sizeof(slv_status_t));
}

static linsolqr_system_t slv5_get_linsolqr_sys(slv_system_t server,
                                               SlvClientToken asys)
{
  slv5_system_t sys;
  (void) server;
  sys = SLV5(asys);
  if (check_system(sys)) return NULL;
  return(sys->J.sys);
}

static linsol_system_t slv5_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, slv5_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,sys->vtot-1,MIF(sys),"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 (slv5_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 {
    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, slv5_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);
  /* rhs 1 for sys->perturbed_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)
slv5_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->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_residuals.vec = create_array(sys->cap,real64);
  sys->newton_residuals.rng = &(sys->J.reg.row);
  sys->perturbed_residuals.vec = create_array(sys->cap,real64);
  sys->perturbed_residuals.rng = &(sys->J.reg.row);
  sys->newton.vec = create_array(sys->cap,real64);
  sys->newton.rng = &(sys->J.reg.col);
  sys->perturbed_newton.vec = create_array(sys->cap,real64);
  sys->perturbed_newton.rng = &(sys->J.reg.col);
  sys->varnewstep.vec = create_array(sys->cap,real64);
  sys->varnewstep.rng = &(sys->J.reg.col);
  sys->varstep.vec = create_array(sys->cap,real64);
  sys->varstep.rng = &(sys->J.reg.col);

}

static
void slv5_dump_internals(slv_system_t server, SlvClientToken sys,int level)
{
  (void) server;
  check_system(sys);
  if (level > 0) {
    FPRINTF(ASCERR,"ERROR:  (slv5) slv5_dump_internals\n");
    FPRINTF(ASCERR,"        slv5 does not dump its internals.\n");
  }
}

/*
 * Here we will check if any fixed or included flags have
 * changed since the last presolve.
 */
static
int32 slv5_dof_changed(slv5_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 slv5_update_linsolqr(slv5_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 slv5_presolve(slv_system_t server, SlvClientToken asys)
{
  struct var_variable **vp;
  struct rel_relation **rp;
  int32 cap, ind;
  int32 matrix_creation_needed = 1;
  slv5_system_t sys;

  sys = SLV5(asys);
  iteration_begins(sys);
  check_system(sys);
  if( sys->vlist == NULL ) {
    FPRINTF(ASCERR,"ERROR:  (slv5) slv5_presolve\n");
    FPRINTF(ASCERR,"        Variable list was never set.\n");
    return;
  }
  if( sys->rlist == NULL && sys->obj == NULL ) {
    FPRINTF(ASCERR,"ERROR:  (slv5) slv5_presolve\n");
    FPRINTF(ASCERR,"        Relation list and objective never set.\n");
    return;
  }

  if(sys->presolved > 0) { /* system has been presolved before */
    if(!slv5_dof_changed(sys) /* no changes in fixed or included flags */
       && PARTITION == sys->J.old_partition) {
#if DEBUG
      FPRINTF(ASCERR,"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 {
    slv5_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;

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


static void slv5_resolve(slv_system_t server, SlvClientToken asys)
{
  struct var_variable **vp;
  struct rel_relation **rp;
  slv5_system_t sys;
  (void) server;
  sys = SLV5(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;

  update_status(sys);
}


static void slv5_iterate(slv_system_t server, SlvClientToken asys)
{
  slv5_system_t sys;
  FILE *mif;
  FILE  *lif;
  boolean first, new_ok, descent_ok;
  int32 m, ds_status, rank_defect;
  int32 optimizing;
  real64  oldpsi;
  real64  time0;
  real64 factor;

  sys = SLV5(asys);
  mif = MIF(sys);
  lif = LIF(sys);
  ds_status = 0; 
  rank_defect = 0;

  if (server == NULL || sys==NULL) return;
  if (check_system(SLV5(sys))) return;
  if( !sys->s.ready_to_solve ) {
    FPRINTF(ASCERR,"ERROR:  (slv5) slv5_iterate\n");
    FPRINTF(ASCERR,"        Not ready to solve.\n");
    return;
  }

  if (sys->s.block.current_block==-1) {
    find_next_unconverged_block(sys);
    update_status(sys);
    return;
  }
  if (SHOW_LESS_IMPT && (sys->s.block.current_size >1 ||
      LIFDS)) {
    debug_delimiter(lif);
  }
  iteration_begins(sys);

  optimizing = sys->obj ? (sys->vused - sys->rank) : 0;

  if( optimizing ) {
    FPRINTF(ASCERR,"ERROR:  (slv5) slv5_iterate\n");
    FPRINTF(ASCERR,"        IPSlv cannot presently optimize.\n");
    sys->s.diverged = 1;
    iteration_ends(sys);
    update_status(sys);
    return;
  }

  /*
   *  Attempt direct solve if appropriate
   */
  if( sys->s.block.iteration == 1 && sys->s.block.current_size == 1 ) {
    struct var_variable *var;
    struct rel_relation *rel;
    var = sys->vlist[mtx_col_to_org(sys->J.mtx,sys->J.reg.col.low)];
    rel = sys->rlist[mtx_row_to_org(sys->J.mtx,sys->J.reg.row.low)];
    if (SHOW_LESS_IMPT && LIFDS) {
      FPRINTF(lif,"%-40s ---> (%d)", "Singleton relation",
              mtx_row_to_org(sys->J.mtx,sys->J.reg.row.low));
      print_rel_name(lif,sys,rel); PUTC('\n',lif);
      FPRINTF(lif,"%-40s ---> (%d)", "Singleton variable",
              mtx_col_to_org(sys->J.mtx,sys->J.reg.col.low));
      print_var_name(lif,sys,var); PUTC('\n',lif);
    }

    /* Attempt direct solve */
    time0=tm_cpu_time();
    ds_status=slv_direct_solve(SERVER,rel,var,mif,FEAS_TOL,IGNORE_BOUNDS,0);
    sys->s.block.functime += (tm_cpu_time()-time0);

    switch( ds_status ) {
    case 0:
      if (SHOW_LESS_IMPT) {
        FPRINTF(lif,"Unable to directly solve symbolically.\n");
      }
      break;
    case 1:
      if (SHOW_LESS_IMPT && LIFDS) {
        FPRINTF(lif,"Directly solved.\n");
      }
      sys->s.calc_ok = calc_residuals(sys);
      if (sys->s.calc_ok) {
        iteration_ends(sys);
        find_next_unconverged_block(sys);
        update_status(sys);
        return;
      }
      FPRINTF(mif,"Direct solve found numerically impossible equation\n");
      FPRINTF(mif,"given variables solved in previous blocks.\n");
    case -1:
      sys->s.inconsistent = TRUE;
      FPRINTF(mif,"No solution exists within the bounds given for:\n");
      print_var_name(mif,sys,var); PUTC('\n',mif);
      FPRINTF(mif,"when inverting relation:\n");
      print_rel_name(mif,sys,rel); PUTC('\n',mif);
      iteration_ends(sys);
      update_status(sys);
      return;
    }
  } /* if direct solve fails with a 0, go on to newton a 1x1 */
  if( !calc_J(sys) ) {
    FPRINTF(MIF(sys),"Jacobian calculation errors detected.\n");
  }

  calc_mu(sys); /* Complementary gap */
  calc_psi(sys);

  scale_system(sys);

  set_factor_options(sys); 
  rank_defect = calc_pivots(sys);

  calc_newton(sys);
  calc_varnewstep(sys); /* only call */

  factor = factor_for_complementary_vars(sys,0);
  factor = TOWARD_BOUNDS * factor;

  apply_step(sys,0,factor);
  calc_newton_residuals(sys);
  calc_muaff(sys); /* Complementary gap */
  calc_sigma(sys); /* Penalty Parameter */
  calc_sigmamu(sys); /* Penalty Parameter time complementary gap */
  restore_variables(sys);
  calc_perturbed_residuals(sys);
  scale_perturbed_system(sys);
  calc_perturbed_newton(sys);

  calc_varstep(sys);
  factor = factor_for_complementary_vars(sys,1);
  factor = TOWARD_BOUNDS * factor;


  first = TRUE;
  new_ok= FALSE;
  descent_ok= FALSE;
  oldpsi = sys->psi;
  m = 0;
#if DEBUG_ITERATION
  FPRINTF(ASCERR,"m = %d \n",m);
#endif /*  DEBUG_ITERATION  */
  while (first || !new_ok || !descent_ok){
    if (first) {
      first = FALSE;
    } else {
      if (!new_ok || !descent_ok ) {
        sys->psi = oldpsi;
        restore_variables(sys);
        m = m + 1;
        factor = factor * pow(RHO,m);
#if DEBUG_ITERATION
        FPRINTF(ASCERR,"m = %d \n",m);
        FPRINTF(ASCERR,"factor = %g \n",factor);
#endif /*  DEBUG_ITERATION  */
        if (m >= 10) {
          FPRINTF(ASCERR,"ERROR:  (slv5) slv5_iterate\n");
          FPRINTF(ASCERR," m is too big already \n");
          sys->s.diverged = 1;
          iteration_ends(sys);
          update_status(sys);
          return;
	}
      } 
    }
    if (sys->eta > 0.0) {
      sys->progress = -1.0 * ALPHA * factor * (1.0 - sys->sigma) *
                      (sys->eta - sys->comp);
    } else {
      sys->progress = 0.0 ;
    }

#if DEBUG_ITERATION
    FPRINTF(ASCERR,"Minimum expected progress = %g \n",sys->progress);
#endif /*  DEBUG_ITERATION  */

    /*
     *  Apply step.
     */
    apply_step(sys,1,factor);

    /*
     *  Check calculations at new point.
     */
    new_ok = (calc_residuals(sys));
 
    if( !new_ok ) {
      continue;
    }

    /*
     *  Check for descent.
     */
    calc_psi(sys);
    scale_residuals(sys);
 
    descent_ok = (sys->psi - oldpsi) < sys->progress;
    if (!descent_ok) {
#if DEBUG_ITERATION
      FPRINTF(ASCERR,"Descent not OK\n");
      FPRINTF(ASCERR,"Descent achieved = %g \n",(sys->psi - oldpsi));
#endif /*  DEBUG_ITERATION  */
    }

  } /* end while */

  step_accepted(sys);

  iteration_ends(sys);
  if( block_feasible(sys) )  {
    if (rank_defect) {
      FPRINTF(mif,"Block %d singular one step before convergence.\n",
        sys->s.block.current_block);
      FPRINTF(mif,
        "You may wish to check for numeric dependency at solution.\n");
    }
    find_next_unconverged_block(sys);
  }
  update_status(sys);
}


static void slv5_solve(slv_system_t server, SlvClientToken asys)
{
  slv5_system_t sys;
  sys = SLV5(asys);
  if (server == NULL || sys==NULL) return;
  if (check_system(sys)) return;
  while( sys->s.ready_to_solve ) slv5_iterate(server,sys);
}

static mtx_matrix_t slv5_get_jacobian(slv_system_t server, SlvClientToken sys)
{
  if (server == NULL || sys==NULL) return NULL;
  if (check_system(SLV5(sys))) return NULL;
  return SLV5(sys)->J.mtx;
}

static int slv5_destroy(slv_system_t server, SlvClientToken asys)
{
  slv5_system_t sys;
  (void) server;
  sys = SLV5(asys);
  if (check_system(sys)) return 1;
  slv_destroy_parms(&(sys->p));
  destroy_matrices(sys);
  destroy_vectors(sys);
  sys->integrity = DESTROYED;
  if (sys->s.cost) ascfree(sys->s.cost);
  ascfree( (POINTER)asys );
  return 0;
}

int slv5_register(SlvFunctionsT *sft)
{
  if (sft==NULL)  {
    FPRINTF(ASCERR,"slv5_register called with NULL pointer\n");
    return 1;
  }

  sft->name = "IPSlv";
  sft->ccreate = slv5_create;
  sft->cdestroy = slv5_destroy;
  sft->celigible = slv5_eligible_solver;
  sft->getdefparam = slv5_get_default_parameters;
  sft->getparam = slv5_get_parameters;
  sft->setparam = slv5_set_parameters;
  sft->getstatus = slv5_get_status;
  sft->solve = slv5_solve;
  sft->presolve = slv5_presolve;
  sft->iterate = slv5_iterate;
  sft->resolve = slv5_resolve;
  sft->getlinsol = slv5_get_linsol_sys;
  sft->getlinsys = slv5_get_linsolqr_sys;
  sft->getsysmtx = slv5_get_jacobian;
  sft->dumpinternals = slv5_dump_internals;
  return 0;
}
#endif /* #else clause of DYNAMIC_IPSLV */
#endif /* #else clause of !STATIC_IPSLV && !DYNAMIC_IPSLV */