glpdmx.c

著名的大规模线性规划求解器源码GLPK.C语言版本,可以修剪.内有详细帮助文档.

/* glpdmx.c (reading/writing data in DIMACS format) */

/***********************************************************************
*  This code is part of GLPK (GNU Linear Programming Kit).
*
*  Copyright (C) 2000,01,02,03,04,05,06,07,08,2009 Andrew Makhorin,
*  Department for Applied Informatics, Moscow Aviation Institute,
*  Moscow, Russia. All rights reserved. E-mail: <[e-mail]>.
*
*  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/>.
***********************************************************************/

#define _GLPSTD_STDIO
#include "glpapi.h"

struct csa
{     /* common storage area */
      jmp_buf jump;
      /* label for go to in case of error */
      const char *fname;
      /* name of input text file */
      XFILE *fp;
      /* stream assigned to input text file */
      int count;
      /* line count */
      int c;
      /* current character */
      char field[31+1];
      /* data field */
      int empty;
      /* warning 'empty line ignored' was printed */
      int nonint;
      /* warning 'non-integer data detected' was printed */
};

static void error(struct csa *csa, const char *fmt, ...)
{     /* print error message and terminate processing */
      va_list arg;
      xprintf("%s:%d: error: ", csa->fname, csa->count);
      va_start(arg, fmt);
      xvprintf(fmt, arg);
      va_end(arg);
      xprintf("\n");
      longjmp(csa->jump, 1);
      /* no return */
}

static void warning(struct csa *csa, const char *fmt, ...)
{     /* print warning message and continue processing */
      va_list arg;
      xprintf("%s:%d: warning: ", csa->fname, csa->count);
      va_start(arg, fmt);
      xvprintf(fmt, arg);
      va_end(arg);
      xprintf("\n");
      return;
}

static void read_char(struct csa *csa)
{     /* read character from input text file */
      int c;
      if (csa->c == '\n') csa->count++;
      c = xfgetc(csa->fp);
      if (c < 0)
      {  if (xferror(csa->fp))
            error(csa, "read error - %s", xerrmsg());
         else if (csa->c == '\n')
            error(csa, "unexpected end of file");
         else
         {  warning(csa, "missing final end of line");
            c = '\n';
         }
      }
      else if (c == '\n')
         ;
      else if (isspace(c))
         c = ' ';
      else if (iscntrl(c))
         error(csa, "invalid control character 0x%02X", c);
      csa->c = c;
      return;
}

static void read_designator(struct csa *csa)
{     /* read one-character line designator */
      xassert(csa->c == '\n');
      read_char(csa);
      for (;;)
      {  /* skip preceding white-space characters */
         while (csa->c == ' ')
            read_char(csa);
         if (csa->c == '\n')
         {  /* ignore empty line */
            if (!csa->empty)
            {  warning(csa, "empty line ignored");
               csa->empty = 1;
            }
            read_char(csa);
         }
         else if (csa->c == 'c')
         {  /* skip comment line */
            while (csa->c != '\n')
               read_char(csa);
            read_char(csa);
         }
         else
         {  /* hmm..., looks like a line designator */
            csa->field[0] = (char)csa->c, csa->field[1] = '\0';
            /* check that it is followed by a white-space character */
            read_char(csa);
            if (!(csa->c == ' ' || csa->c == '\n'))
               error(csa, "line designator missing or invalid");
            break;
         }
      }
      return;
}

static void read_field(struct csa *csa)
{     /* read data field */
      int len = 0;
      /* skip preceding white-space characters */
      while (csa->c == ' ')
         read_char(csa);
      /* scan data field */
      if (csa->c == '\n')
         error(csa, "unexpected end of line");
      while (!(csa->c == ' ' || csa->c == '\n'))
      {  if (len == sizeof(csa->field)-1)
            error(csa, "data field `%.*s...' too long",
               sizeof(csa->field)-1, csa->field);
         csa->field[len++] = (char)csa->c;
         read_char(csa);
      }
      csa->field[len] = '\0';
      return;
}

static void end_of_line(struct csa *csa)
{     /* skip white-space characters until end of line */
      while (csa->c == ' ')
         read_char(csa);
      if (csa->c != '\n')
         error(csa, "too many data fields specified");
      return;
}

static void check_int(struct csa *csa, double num)
{     /* print a warning if non-integer data are detected */
      if (!csa->nonint && num != floor(num))
      {  warning(csa, "non-integer data detected");
         csa->nonint = 1;
      }
      return;
}

/***********************************************************************
*  NAME
*
*  glp_read_mincost - read min-cost flow problem data in DIMACS format
*
*  SYNOPSIS
*
*  int glp_read_mincost(glp_graph *G, int v_rhs, int a_low, int a_cap,
*     int a_cost, const char *fname);
*
*  DESCRIPTION
*
*  The routine glp_read_mincost reads minimum cost flow problem data in
*  DIMACS format from a text file.
*
*  RETURNS
*
*  If the operation was successful, the routine returns zero. Otherwise
*  it prints an error message and returns non-zero. */

int glp_read_mincost(glp_graph *G, int v_rhs, int a_low, int a_cap,
      int a_cost, const char *fname)
{     struct csa _csa, *csa = &_csa;
      glp_vertex *v;
      glp_arc *a;
      int i, j, k, nv, na, ret = 0;
      double rhs, low, cap, cost;
      char *flag = NULL;
      if (v_rhs >= 0 && v_rhs > G->v_size - (int)sizeof(double))
         xerror("glp_read_mincost: v_rhs = %d; invalid offset\n",
            v_rhs);
      if (a_low >= 0 && a_low > G->a_size - (int)sizeof(double))
         xerror("glp_read_mincost: a_low = %d; invalid offset\n",
            a_low);
      if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double))
         xerror("glp_read_mincost: a_cap = %d; invalid offset\n",
            a_cap);
      if (a_cost >= 0 && a_cost > G->a_size - (int)sizeof(double))
         xerror("glp_read_mincost: a_cost = %d; invalid offset\n",
            a_cost);
      glp_erase_graph(G, G->v_size, G->a_size);
      if (setjmp(csa->jump))
      {  ret = 1;
         goto done;
      }
      csa->fname = fname;
      csa->fp = NULL;
      csa->count = 0;
      csa->c = '\n';
      csa->field[0] = '\0';
      csa->empty = csa->nonint = 0;
      xprintf("Reading min-cost flow problem data from `%s'...\n",
         fname);
      csa->fp = xfopen(fname, "r");
      if (csa->fp == NULL)
      {  xprintf("Unable to open `%s' - %s\n", fname, xerrmsg());
         longjmp(csa->jump, 1);
      }
      /* read problem line */
      read_designator(csa);
      if (strcmp(csa->field, "p") != 0)
         error(csa, "problem line missing or invalid");
      read_field(csa);
      if (strcmp(csa->field, "min") != 0)
         error(csa, "wrong problem designator; `min' expected");
      read_field(csa);
      if (!(str2int(csa->field, &nv) == 0 && nv >= 0))
         error(csa, "number of nodes missing or invalid");
      read_field(csa);
      if (!(str2int(csa->field, &na) == 0 && na >= 0))
         error(csa, "number of arcs missing or invalid");
      xprintf("Flow network has %d node%s and %d arc%s\n",
         nv, nv == 1 ? "" : "s", na, na == 1 ? "" : "s");
      if (nv > 0) glp_add_vertices(G, nv);
      end_of_line(csa);
      /* read node descriptor lines */
      flag = xcalloc(1+nv, sizeof(char));
      memset(&flag[1], 0, nv * sizeof(char));
      if (v_rhs >= 0)
      {  rhs = 0.0;
         for (i = 1; i <= nv; i++)
         {  v = G->v[i];
            memcpy((char *)v->data + v_rhs, &rhs, sizeof(double));
         }
      }
      for (;;)
      {  read_designator(csa);
         if (strcmp(csa->field, "n") != 0) break;
         read_field(csa);
         if (str2int(csa->field, &i) != 0)
            error(csa, "node number missing or invalid");
         if (!(1 <= i && i <= nv))
            error(csa, "node number %d out of range", i);
         if (flag[i])
            error(csa, "duplicate descriptor of node %d", i);
         read_field(csa);
         if (str2num(csa->field, &rhs) != 0)
            error(csa, "node supply/demand missing or invalid");
         check_int(csa, rhs);
         if (v_rhs >= 0)
         {  v = G->v[i];
            memcpy((char *)v->data + v_rhs, &rhs, sizeof(double));
         }
         flag[i] = 1;
         end_of_line(csa);
      }
      xfree(flag), flag = NULL;
      /* read arc descriptor lines */
      for (k = 1; k <= na; k++)
      {  if (k > 1) read_designator(csa);
         if (strcmp(csa->field, "a") != 0)
            error(csa, "wrong line designator; `a' expected");
         read_field(csa);
         if (str2int(csa->field, &i) != 0)
            error(csa, "starting node number missing or invalid");
         if (!(1 <= i && i <= nv))
            error(csa, "starting node number %d out of range", i);
         read_field(csa);
         if (str2int(csa->field, &j) != 0)
            error(csa, "ending node number missing or invalid");
         if (!(1 <= j && j <= nv))
            error(csa, "ending node number %d out of range", j);
         read_field(csa);
         if (!(str2num(csa->field, &low) == 0 && low >= 0.0))
            error(csa, "lower bound of arc flow missing or invalid");
         check_int(csa, low);
         read_field(csa);
         if (!(str2num(csa->field, &cap) == 0 && cap >= low))
            error(csa, "upper bound of arc flow missing or invalid");
         check_int(csa, cap);
         read_field(csa);
         if (str2num(csa->field, &cost) != 0)
            error(csa, "per-unit cost of arc flow missing or invalid");
         check_int(csa, cost);
         a = glp_add_arc(G, i, j);
         if (a_low >= 0)
            memcpy((char *)a->data + a_low, &low, sizeof(double));
         if (a_cap >= 0)