COIN-OR::LEMON - Graph Library

source: glpk-cmake/src/glpapi02.c @ 1:c445c931472f

Last change on this file since 1:c445c931472f was 1:c445c931472f, checked in by Alpar Juttner <alpar@…>, 10 years ago

Import glpk-4.45

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1/* glpapi02.c (problem retrieving routines) */
2
3/***********************************************************************
4*  This code is part of GLPK (GNU Linear Programming Kit).
5*
6*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
7*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,
8*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.
9*  E-mail: <mao@gnu.org>.
10*
11*  GLPK is free software: you can redistribute it and/or modify it
12*  under the terms of the GNU General Public License as published by
13*  the Free Software Foundation, either version 3 of the License, or
14*  (at your option) any later version.
15*
16*  GLPK is distributed in the hope that it will be useful, but WITHOUT
17*  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
18*  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
19*  License for more details.
20*
21*  You should have received a copy of the GNU General Public License
22*  along with GLPK. If not, see <http://www.gnu.org/licenses/>.
23***********************************************************************/
24
25#include "glpapi.h"
26
27/***********************************************************************
28*  NAME
29*
30*  glp_get_prob_name - retrieve problem name
31*
32*  SYNOPSIS
33*
34*  const char *glp_get_prob_name(glp_prob *lp);
35*
36*  RETURNS
37*
38*  The routine glp_get_prob_name returns a pointer to an internal
39*  buffer, which contains symbolic name of the problem. However, if the
40*  problem has no assigned name, the routine returns NULL. */
41
42const char *glp_get_prob_name(glp_prob *lp)
43{     char *name;
44      name = lp->name;
45      return name;
46}
47
48/***********************************************************************
49*  NAME
50*
51*  glp_get_obj_name - retrieve objective function name
52*
53*  SYNOPSIS
54*
55*  const char *glp_get_obj_name(glp_prob *lp);
56*
57*  RETURNS
58*
59*  The routine glp_get_obj_name returns a pointer to an internal
60*  buffer, which contains a symbolic name of the objective function.
61*  However, if the objective function has no assigned name, the routine
62*  returns NULL. */
63
64const char *glp_get_obj_name(glp_prob *lp)
65{     char *name;
66      name = lp->obj;
67      return name;
68}
69
70/***********************************************************************
71*  NAME
72*
73*  glp_get_obj_dir - retrieve optimization direction flag
74*
75*  SYNOPSIS
76*
77*  int glp_get_obj_dir(glp_prob *lp);
78*
79*  RETURNS
80*
81*  The routine glp_get_obj_dir returns the optimization direction flag
82*  (i.e. "sense" of the objective function):
83*
84*  GLP_MIN - minimization;
85*  GLP_MAX - maximization. */
86
87int glp_get_obj_dir(glp_prob *lp)
88{     int dir = lp->dir;
89      return dir;
90}
91
92/***********************************************************************
93*  NAME
94*
95*  glp_get_num_rows - retrieve number of rows
96*
97*  SYNOPSIS
98*
99*  int glp_get_num_rows(glp_prob *lp);
100*
101*  RETURNS
102*
103*  The routine glp_get_num_rows returns the current number of rows in
104*  the specified problem object. */
105
106int glp_get_num_rows(glp_prob *lp)
107{     int m = lp->m;
108      return m;
109}
110
111/***********************************************************************
112*  NAME
113*
114*  glp_get_num_cols - retrieve number of columns
115*
116*  SYNOPSIS
117*
118*  int glp_get_num_cols(glp_prob *lp);
119*
120*  RETURNS
121*
122*  The routine glp_get_num_cols returns the current number of columns
123*  in the specified problem object. */
124
125int glp_get_num_cols(glp_prob *lp)
126{     int n = lp->n;
127      return n;
128}
129
130/***********************************************************************
131*  NAME
132*
133*  glp_get_row_name - retrieve row name
134*
135*  SYNOPSIS
136*
137*  const char *glp_get_row_name(glp_prob *lp, int i);
138*
139*  RETURNS
140*
141*  The routine glp_get_row_name returns a pointer to an internal
142*  buffer, which contains symbolic name of i-th row. However, if i-th
143*  row has no assigned name, the routine returns NULL. */
144
145const char *glp_get_row_name(glp_prob *lp, int i)
146{     char *name;
147      if (!(1 <= i && i <= lp->m))
148         xerror("glp_get_row_name: i = %d; row number out of range\n",
149            i);
150      name = lp->row[i]->name;
151      return name;
152}
153
154/***********************************************************************
155*  NAME
156*
157*  glp_get_col_name - retrieve column name
158*
159*  SYNOPSIS
160*
161*  const char *glp_get_col_name(glp_prob *lp, int j);
162*
163*  RETURNS
164*
165*  The routine glp_get_col_name returns a pointer to an internal
166*  buffer, which contains symbolic name of j-th column. However, if j-th
167*  column has no assigned name, the routine returns NULL. */
168
169const char *glp_get_col_name(glp_prob *lp, int j)
170{     char *name;
171      if (!(1 <= j && j <= lp->n))
172         xerror("glp_get_col_name: j = %d; column number out of range\n"
173            , j);
174      name = lp->col[j]->name;
175      return name;
176}
177
178/***********************************************************************
179*  NAME
180*
181*  glp_get_row_type - retrieve row type
182*
183*  SYNOPSIS
184*
185*  int glp_get_row_type(glp_prob *lp, int i);
186*
187*  RETURNS
188*
189*  The routine glp_get_row_type returns the type of i-th row, i.e. the
190*  type of corresponding auxiliary variable, as follows:
191*
192*  GLP_FR - free (unbounded) variable;
193*  GLP_LO - variable with lower bound;
194*  GLP_UP - variable with upper bound;
195*  GLP_DB - double-bounded variable;
196*  GLP_FX - fixed variable. */
197
198int glp_get_row_type(glp_prob *lp, int i)
199{     if (!(1 <= i && i <= lp->m))
200         xerror("glp_get_row_type: i = %d; row number out of range\n",
201            i);
202      return lp->row[i]->type;
203}
204
205/***********************************************************************
206*  NAME
207*
208*  glp_get_row_lb - retrieve row lower bound
209*
210*  SYNOPSIS
211*
212*  double glp_get_row_lb(glp_prob *lp, int i);
213*
214*  RETURNS
215*
216*  The routine glp_get_row_lb returns the lower bound of i-th row, i.e.
217*  the lower bound of corresponding auxiliary variable. However, if the
218*  row has no lower bound, the routine returns -DBL_MAX. */
219
220double glp_get_row_lb(glp_prob *lp, int i)
221{     double lb;
222      if (!(1 <= i && i <= lp->m))
223         xerror("glp_get_row_lb: i = %d; row number out of range\n", i);
224      switch (lp->row[i]->type)
225      {  case GLP_FR:
226         case GLP_UP:
227            lb = -DBL_MAX; break;
228         case GLP_LO:
229         case GLP_DB:
230         case GLP_FX:
231            lb = lp->row[i]->lb; break;
232         default:
233            xassert(lp != lp);
234      }
235      return lb;
236}
237
238/***********************************************************************
239*  NAME
240*
241*  glp_get_row_ub - retrieve row upper bound
242*
243*  SYNOPSIS
244*
245*  double glp_get_row_ub(glp_prob *lp, int i);
246*
247*  RETURNS
248*
249*  The routine glp_get_row_ub returns the upper bound of i-th row, i.e.
250*  the upper bound of corresponding auxiliary variable. However, if the
251*  row has no upper bound, the routine returns +DBL_MAX. */
252
253double glp_get_row_ub(glp_prob *lp, int i)
254{     double ub;
255      if (!(1 <= i && i <= lp->m))
256         xerror("glp_get_row_ub: i = %d; row number out of range\n", i);
257      switch (lp->row[i]->type)
258      {  case GLP_FR:
259         case GLP_LO:
260            ub = +DBL_MAX; break;
261         case GLP_UP:
262         case GLP_DB:
263         case GLP_FX:
264            ub = lp->row[i]->ub; break;
265         default:
266            xassert(lp != lp);
267      }
268      return ub;
269}
270
271/***********************************************************************
272*  NAME
273*
274*  glp_get_col_type - retrieve column type
275*
276*  SYNOPSIS
277*
278*  int glp_get_col_type(glp_prob *lp, int j);
279*
280*  RETURNS
281*
282*  The routine glp_get_col_type returns the type of j-th column, i.e.
283*  the type of corresponding structural variable, as follows:
284*
285*  GLP_FR - free (unbounded) variable;
286*  GLP_LO - variable with lower bound;
287*  GLP_UP - variable with upper bound;
288*  GLP_DB - double-bounded variable;
289*  GLP_FX - fixed variable. */
290
291int glp_get_col_type(glp_prob *lp, int j)
292{     if (!(1 <= j && j <= lp->n))
293         xerror("glp_get_col_type: j = %d; column number out of range\n"
294            , j);
295      return lp->col[j]->type;
296}
297
298/***********************************************************************
299*  NAME
300*
301*  glp_get_col_lb - retrieve column lower bound
302*
303*  SYNOPSIS
304*
305*  double glp_get_col_lb(glp_prob *lp, int j);
306*
307*  RETURNS
308*
309*  The routine glp_get_col_lb returns the lower bound of j-th column,
310*  i.e. the lower bound of corresponding structural variable. However,
311*  if the column has no lower bound, the routine returns -DBL_MAX. */
312
313double glp_get_col_lb(glp_prob *lp, int j)
314{     double lb;
315      if (!(1 <= j && j <= lp->n))
316         xerror("glp_get_col_lb: j = %d; column number out of range\n",
317            j);
318      switch (lp->col[j]->type)
319      {  case GLP_FR:
320         case GLP_UP:
321            lb = -DBL_MAX; break;
322         case GLP_LO:
323         case GLP_DB:
324         case GLP_FX:
325            lb = lp->col[j]->lb; break;
326         default:
327            xassert(lp != lp);
328      }
329      return lb;
330}
331
332/***********************************************************************
333*  NAME
334*
335*  glp_get_col_ub - retrieve column upper bound
336*
337*  SYNOPSIS
338*
339*  double glp_get_col_ub(glp_prob *lp, int j);
340*
341*  RETURNS
342*
343*  The routine glp_get_col_ub returns the upper bound of j-th column,
344*  i.e. the upper bound of corresponding structural variable. However,
345*  if the column has no upper bound, the routine returns +DBL_MAX. */
346
347double glp_get_col_ub(glp_prob *lp, int j)
348{     double ub;
349      if (!(1 <= j && j <= lp->n))
350         xerror("glp_get_col_ub: j = %d; column number out of range\n",
351            j);
352      switch (lp->col[j]->type)
353      {  case GLP_FR:
354         case GLP_LO:
355            ub = +DBL_MAX; break;
356         case GLP_UP:
357         case GLP_DB:
358         case GLP_FX:
359            ub = lp->col[j]->ub; break;
360         default:
361            xassert(lp != lp);
362      }
363      return ub;
364}
365
366/***********************************************************************
367*  NAME
368*
369*  glp_get_obj_coef - retrieve obj. coefficient or constant term
370*
371*  SYNOPSIS
372*
373*  double glp_get_obj_coef(glp_prob *lp, int j);
374*
375*  RETURNS
376*
377*  The routine glp_get_obj_coef returns the objective coefficient at
378*  j-th structural variable (column) of the specified problem object.
379*
380*  If the parameter j is zero, the routine returns the constant term
381*  ("shift") of the objective function. */
382
383double glp_get_obj_coef(glp_prob *lp, int j)
384{     if (!(0 <= j && j <= lp->n))
385         xerror("glp_get_obj_coef: j = %d; column number out of range\n"
386            , j);
387      return j == 0 ? lp->c0 : lp->col[j]->coef;
388}
389
390/***********************************************************************
391*  NAME
392*
393*  glp_get_num_nz - retrieve number of constraint coefficients
394*
395*  SYNOPSIS
396*
397*  int glp_get_num_nz(glp_prob *lp);
398*
399*  RETURNS
400*
401*  The routine glp_get_num_nz returns the number of (non-zero) elements
402*  in the constraint matrix of the specified problem object. */
403
404int glp_get_num_nz(glp_prob *lp)
405{     int nnz = lp->nnz;
406      return nnz;
407}
408
409/***********************************************************************
410*  NAME
411*
412*  glp_get_mat_row - retrieve row of the constraint matrix
413*
414*  SYNOPSIS
415*
416*  int glp_get_mat_row(glp_prob *lp, int i, int ind[], double val[]);
417*
418*  DESCRIPTION
419*
420*  The routine glp_get_mat_row scans (non-zero) elements of i-th row
421*  of the constraint matrix of the specified problem object and stores
422*  their column indices and numeric values to locations ind[1], ...,
423*  ind[len] and val[1], ..., val[len], respectively, where 0 <= len <= n
424*  is the number of elements in i-th row, n is the number of columns.
425*
426*  The parameter ind and/or val can be specified as NULL, in which case
427*  corresponding information is not stored.
428*
429*  RETURNS
430*
431*  The routine glp_get_mat_row returns the length len, i.e. the number
432*  of (non-zero) elements in i-th row. */
433
434int glp_get_mat_row(glp_prob *lp, int i, int ind[], double val[])
435{     GLPAIJ *aij;
436      int len;
437      if (!(1 <= i && i <= lp->m))
438         xerror("glp_get_mat_row: i = %d; row number out of range\n",
439            i);
440      len = 0;
441      for (aij = lp->row[i]->ptr; aij != NULL; aij = aij->r_next)
442      {  len++;
443         if (ind != NULL) ind[len] = aij->col->j;
444         if (val != NULL) val[len] = aij->val;
445      }
446      xassert(len <= lp->n);
447      return len;
448}
449
450/***********************************************************************
451*  NAME
452*
453*  glp_get_mat_col - retrieve column of the constraint matrix
454*
455*  SYNOPSIS
456*
457*  int glp_get_mat_col(glp_prob *lp, int j, int ind[], double val[]);
458*
459*  DESCRIPTION
460*
461*  The routine glp_get_mat_col scans (non-zero) elements of j-th column
462*  of the constraint matrix of the specified problem object and stores
463*  their row indices and numeric values to locations ind[1], ...,
464*  ind[len] and val[1], ..., val[len], respectively, where 0 <= len <= m
465*  is the number of elements in j-th column, m is the number of rows.
466*
467*  The parameter ind or/and val can be specified as NULL, in which case
468*  corresponding information is not stored.
469*
470*  RETURNS
471*
472*  The routine glp_get_mat_col returns the length len, i.e. the number
473*  of (non-zero) elements in j-th column. */
474
475int glp_get_mat_col(glp_prob *lp, int j, int ind[], double val[])
476{     GLPAIJ *aij;
477      int len;
478      if (!(1 <= j && j <= lp->n))
479         xerror("glp_get_mat_col: j = %d; column number out of range\n",
480            j);
481      len = 0;
482      for (aij = lp->col[j]->ptr; aij != NULL; aij = aij->c_next)
483      {  len++;
484         if (ind != NULL) ind[len] = aij->row->i;
485         if (val != NULL) val[len] = aij->val;
486      }
487      xassert(len <= lp->m);
488      return len;
489}
490
491/* eof */
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