/* glpapi02.c (problem retrieving routines) */

/***********************************************************************

*  This code is part of GLPK (GNU Linear Programming Kit).

*

*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,

*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,

*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.

*  E-mail: <mao@gnu.org>.

*

*  GLPK 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 3 of the License, or

*  (at your option) any later version.

*

*  GLPK is distributed in the 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 GLPK. If not, see <http://www.gnu.org/licenses/>.

***********************************************************************/

#include "glpapi.h"

/***********************************************************************

*  NAME

*

*  glp_get_prob_name - retrieve problem name

*

*  SYNOPSIS

*

*  const char *glp_get_prob_name(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_prob_name returns a pointer to an internal

*  buffer, which contains symbolic name of the problem. However, if the

*  problem has no assigned name, the routine returns NULL. */

const char *glp_get_prob_name(glp_prob *lp)

{     char *name;

      name = lp->name;

      return name;

}

/***********************************************************************

*  NAME

*

*  glp_get_obj_name - retrieve objective function name

*

*  SYNOPSIS

*

*  const char *glp_get_obj_name(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_obj_name returns a pointer to an internal

*  buffer, which contains a symbolic name of the objective function.

*  However, if the objective function has no assigned name, the routine

*  returns NULL. */

const char *glp_get_obj_name(glp_prob *lp)

{     char *name;

      name = lp->obj;

      return name;

}

/***********************************************************************

*  NAME

*

*  glp_get_obj_dir - retrieve optimization direction flag

*

*  SYNOPSIS

*

*  int glp_get_obj_dir(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_obj_dir returns the optimization direction flag

*  (i.e. "sense" of the objective function):

*

*  GLP_MIN - minimization;

*  GLP_MAX - maximization. */

int glp_get_obj_dir(glp_prob *lp)

{     int dir = lp->dir;

      return dir;

}

/***********************************************************************

*  NAME

*

*  glp_get_num_rows - retrieve number of rows

*

*  SYNOPSIS

*

*  int glp_get_num_rows(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_num_rows returns the current number of rows in

*  the specified problem object. */

int glp_get_num_rows(glp_prob *lp)

{     int m = lp->m;

      return m;

}

/***********************************************************************

*  NAME

*

*  glp_get_num_cols - retrieve number of columns

*

*  SYNOPSIS

*

*  int glp_get_num_cols(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_num_cols returns the current number of columns

*  in the specified problem object. */

int glp_get_num_cols(glp_prob *lp)

{     int n = lp->n;

      return n;

}

/***********************************************************************

*  NAME

*

*  glp_get_row_name - retrieve row name

*

*  SYNOPSIS

*

*  const char *glp_get_row_name(glp_prob *lp, int i);

*

*  RETURNS

*

*  The routine glp_get_row_name returns a pointer to an internal

*  buffer, which contains symbolic name of i-th row. However, if i-th

*  row has no assigned name, the routine returns NULL. */

const char *glp_get_row_name(glp_prob *lp, int i)

{     char *name;

      if (!(1 <= i && i <= lp->m))

         xerror("glp_get_row_name: i = %d; row number out of range\n",

            i);

      name = lp->row[i]->name;

      return name;

}

/***********************************************************************

*  NAME

*

*  glp_get_col_name - retrieve column name

*

*  SYNOPSIS

*

*  const char *glp_get_col_name(glp_prob *lp, int j);

*

*  RETURNS

*

*  The routine glp_get_col_name returns a pointer to an internal

*  buffer, which contains symbolic name of j-th column. However, if j-th

*  column has no assigned name, the routine returns NULL. */

const char *glp_get_col_name(glp_prob *lp, int j)

{     char *name;

      if (!(1 <= j && j <= lp->n))

         xerror("glp_get_col_name: j = %d; column number out of range\n"

            , j);

      name = lp->col[j]->name;

      return name;

}

/***********************************************************************

*  NAME

*

*  glp_get_row_type - retrieve row type

*

*  SYNOPSIS

*

*  int glp_get_row_type(glp_prob *lp, int i);

*

*  RETURNS

*

*  The routine glp_get_row_type returns the type of i-th row, i.e. the

*  type of corresponding auxiliary variable, as follows:

*

*  GLP_FR - free (unbounded) variable;

*  GLP_LO - variable with lower bound;

*  GLP_UP - variable with upper bound;

*  GLP_DB - double-bounded variable;

*  GLP_FX - fixed variable. */

int glp_get_row_type(glp_prob *lp, int i)

{     if (!(1 <= i && i <= lp->m))

         xerror("glp_get_row_type: i = %d; row number out of range\n",

            i);

      return lp->row[i]->type;

}

/***********************************************************************

*  NAME

*

*  glp_get_row_lb - retrieve row lower bound

*

*  SYNOPSIS

*

*  double glp_get_row_lb(glp_prob *lp, int i);

*

*  RETURNS

*

*  The routine glp_get_row_lb returns the lower bound of i-th row, i.e.

*  the lower bound of corresponding auxiliary variable. However, if the

*  row has no lower bound, the routine returns -DBL_MAX. */

double glp_get_row_lb(glp_prob *lp, int i)

{     double lb;

      if (!(1 <= i && i <= lp->m))

         xerror("glp_get_row_lb: i = %d; row number out of range\n", i);

      switch (lp->row[i]->type)

      {  case GLP_FR:

         case GLP_UP:

            lb = -DBL_MAX; break;

         case GLP_LO:

         case GLP_DB:

         case GLP_FX:

            lb = lp->row[i]->lb; break;

         default:

            xassert(lp != lp);

      }

      return lb;

}

/***********************************************************************

*  NAME

*

*  glp_get_row_ub - retrieve row upper bound

*

*  SYNOPSIS

*

*  double glp_get_row_ub(glp_prob *lp, int i);

*

*  RETURNS

*

*  The routine glp_get_row_ub returns the upper bound of i-th row, i.e.

*  the upper bound of corresponding auxiliary variable. However, if the

*  row has no upper bound, the routine returns +DBL_MAX. */

double glp_get_row_ub(glp_prob *lp, int i)

{     double ub;

      if (!(1 <= i && i <= lp->m))

         xerror("glp_get_row_ub: i = %d; row number out of range\n", i);

      switch (lp->row[i]->type)

      {  case GLP_FR:

         case GLP_LO:

            ub = +DBL_MAX; break;

         case GLP_UP:

         case GLP_DB:

         case GLP_FX:

            ub = lp->row[i]->ub; break;

         default:

            xassert(lp != lp);

      }

      return ub;

}

/***********************************************************************

*  NAME

*

*  glp_get_col_type - retrieve column type

*

*  SYNOPSIS

*

*  int glp_get_col_type(glp_prob *lp, int j);

*

*  RETURNS

*

*  The routine glp_get_col_type returns the type of j-th column, i.e.

*  the type of corresponding structural variable, as follows:

*

*  GLP_FR - free (unbounded) variable;

*  GLP_LO - variable with lower bound;

*  GLP_UP - variable with upper bound;

*  GLP_DB - double-bounded variable;

*  GLP_FX - fixed variable. */

int glp_get_col_type(glp_prob *lp, int j)

{     if (!(1 <= j && j <= lp->n))

         xerror("glp_get_col_type: j = %d; column number out of range\n"

            , j);

      return lp->col[j]->type;

}

/***********************************************************************

*  NAME

*

*  glp_get_col_lb - retrieve column lower bound

*

*  SYNOPSIS

*

*  double glp_get_col_lb(glp_prob *lp, int j);

*

*  RETURNS

*

*  The routine glp_get_col_lb returns the lower bound of j-th column,

*  i.e. the lower bound of corresponding structural variable. However,

*  if the column has no lower bound, the routine returns -DBL_MAX. */

double glp_get_col_lb(glp_prob *lp, int j)

{     double lb;

      if (!(1 <= j && j <= lp->n))

         xerror("glp_get_col_lb: j = %d; column number out of range\n",

            j);

      switch (lp->col[j]->type)

      {  case GLP_FR:

         case GLP_UP:

            lb = -DBL_MAX; break;

         case GLP_LO:

         case GLP_DB:

         case GLP_FX:

            lb = lp->col[j]->lb; break;

         default:

            xassert(lp != lp);

      }

      return lb;

}

/***********************************************************************

*  NAME

*

*  glp_get_col_ub - retrieve column upper bound

*

*  SYNOPSIS

*

*  double glp_get_col_ub(glp_prob *lp, int j);

*

*  RETURNS

*

*  The routine glp_get_col_ub returns the upper bound of j-th column,

*  i.e. the upper bound of corresponding structural variable. However,

*  if the column has no upper bound, the routine returns +DBL_MAX. */

double glp_get_col_ub(glp_prob *lp, int j)

{     double ub;

      if (!(1 <= j && j <= lp->n))

         xerror("glp_get_col_ub: j = %d; column number out of range\n",

            j);

      switch (lp->col[j]->type)

      {  case GLP_FR:

         case GLP_LO:

            ub = +DBL_MAX; break;

         case GLP_UP:

         case GLP_DB:

         case GLP_FX:

            ub = lp->col[j]->ub; break;

         default:

            xassert(lp != lp);

      }

      return ub;

}

/***********************************************************************

*  NAME

*

*  glp_get_obj_coef - retrieve obj. coefficient or constant term

*

*  SYNOPSIS

*

*  double glp_get_obj_coef(glp_prob *lp, int j);

*

*  RETURNS

*

*  The routine glp_get_obj_coef returns the objective coefficient at

*  j-th structural variable (column) of the specified problem object.

*

*  If the parameter j is zero, the routine returns the constant term

*  ("shift") of the objective function. */

double glp_get_obj_coef(glp_prob *lp, int j)

{     if (!(0 <= j && j <= lp->n))

         xerror("glp_get_obj_coef: j = %d; column number out of range\n"

            , j);

      return j == 0 ? lp->c0 : lp->col[j]->coef;

}

/***********************************************************************

*  NAME

*

*  glp_get_num_nz - retrieve number of constraint coefficients

*

*  SYNOPSIS

*

*  int glp_get_num_nz(glp_prob *lp);

*

*  RETURNS

*

*  The routine glp_get_num_nz returns the number of (non-zero) elements

*  in the constraint matrix of the specified problem object. */

int glp_get_num_nz(glp_prob *lp)

{     int nnz = lp->nnz;

      return nnz;

}

/***********************************************************************

*  NAME

*

*  glp_get_mat_row - retrieve row of the constraint matrix

*

*  SYNOPSIS

*

*  int glp_get_mat_row(glp_prob *lp, int i, int ind[], double val[]);

*

*  DESCRIPTION

*

*  The routine glp_get_mat_row scans (non-zero) elements of i-th row

*  of the constraint matrix of the specified problem object and stores

*  their column indices and numeric values to locations ind[1], ...,

*  ind[len] and val[1], ..., val[len], respectively, where 0 <= len <= n

*  is the number of elements in i-th row, n is the number of columns.

*

*  The parameter ind and/or val can be specified as NULL, in which case

*  corresponding information is not stored.

*

*  RETURNS

*

*  The routine glp_get_mat_row returns the length len, i.e. the number

*  of (non-zero) elements in i-th row. */

int glp_get_mat_row(glp_prob *lp, int i, int ind[], double val[])

{     GLPAIJ *aij;

      int len;

      if (!(1 <= i && i <= lp->m))

         xerror("glp_get_mat_row: i = %d; row number out of range\n",

            i);

      len = 0;

      for (aij = lp->row[i]->ptr; aij != NULL; aij = aij->r_next)

      {  len++;

         if (ind != NULL) ind[len] = aij->col->j;

         if (val != NULL) val[len] = aij->val;

      }

      xassert(len <= lp->n);

      return len;

}

/***********************************************************************

*  NAME

*

*  glp_get_mat_col - retrieve column of the constraint matrix

*

*  SYNOPSIS

*

*  int glp_get_mat_col(glp_prob *lp, int j, int ind[], double val[]);

*

*  DESCRIPTION

*

*  The routine glp_get_mat_col scans (non-zero) elements of j-th column

*  of the constraint matrix of the specified problem object and stores

*  their row indices and numeric values to locations ind[1], ...,

*  ind[len] and val[1], ..., val[len], respectively, where 0 <= len <= m

*  is the number of elements in j-th column, m is the number of rows.

*

*  The parameter ind or/and val can be specified as NULL, in which case

*  corresponding information is not stored.

*

*  RETURNS

*

*  The routine glp_get_mat_col returns the length len, i.e. the number

*  of (non-zero) elements in j-th column. */

int glp_get_mat_col(glp_prob *lp, int j, int ind[], double val[])

{     GLPAIJ *aij;

      int len;

      if (!(1 <= j && j <= lp->n))

         xerror("glp_get_mat_col: j = %d; column number out of range\n",

            j);

      len = 0;

      for (aij = lp->col[j]->ptr; aij != NULL; aij = aij->c_next)

      {  len++;

         if (ind != NULL) ind[len] = aij->row->i;

         if (val != NULL) val[len] = aij->val;

      }

      xassert(len <= lp->m);

      return len;

}

/* eof */