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.

            memcpy((char *)a->data + a_cap, &cap, sizeof(double));
         if (a_cost >= 0)
            memcpy((char *)a->data + a_cost, &cost, sizeof(double));
         end_of_line(csa);
      }
      xprintf("%d lines were read\n", csa->count);
done: if (ret) glp_erase_graph(G, G->v_size, G->a_size);
      if (csa->fp != NULL) xfclose(csa->fp);
      if (flag != NULL) xfree(flag);
      return ret;
}

/***********************************************************************
*  NAME
*
*  glp_write_mincost - write min-cost flow problem data in DIMACS format
*
*  SYNOPSIS
*
*  int glp_write_mincost(glp_graph *G, int v_rhs, int a_low, int a_cap,
*     int a_cost, const char *fname);
*
*  DESCRIPTION
*
*  The routine glp_write_mincost writes minimum cost flow problem data
*  in DIMACS format to 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_write_mincost(glp_graph *G, int v_rhs, int a_low, int a_cap,
      int a_cost, const char *fname)
{     XFILE *fp;
      glp_vertex *v;
      glp_arc *a;
      int i, count = 0, ret;
      double rhs, low, cap, cost;
      if (v_rhs >= 0 && v_rhs > G->v_size - (int)sizeof(double))
         xerror("glp_write_mincost: v_rhs = %d; invalid offset\n",
            v_rhs);
      if (a_low >= 0 && a_low > G->a_size - (int)sizeof(double))
         xerror("glp_write_mincost: a_low = %d; invalid offset\n",
            a_low);
      if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double))
         xerror("glp_write_mincost: a_cap = %d; invalid offset\n",
            a_cap);
      if (a_cost >= 0 && a_cost > G->a_size - (int)sizeof(double))
         xerror("glp_write_mincost: a_cost = %d; invalid offset\n",
            a_cost);
      xprintf("Writing min-cost flow problem data to `%s'...\n",
         fname);
      fp = xfopen(fname, "w");
      if (fp == NULL)
      {  xprintf("Unable to create `%s' - %s\n", fname, xerrmsg());
         ret = 1;
         goto done;
      }
      xfprintf(fp, "c %s\n",
         G->name == NULL ? "unknown" : G->name), count++;
      xfprintf(fp, "p min %d %d\n", G->nv, G->na), count++;
      if (v_rhs >= 0)
      {  for (i = 1; i <= G->nv; i++)
         {  v = G->v[i];
            memcpy(&rhs, (char *)v->data + v_rhs, sizeof(double));
            if (rhs != 0.0)
               xfprintf(fp, "n %d %.*g\n", i, DBL_DIG, rhs), count++;
         }
      }
      for (i = 1; i <= G->nv; i++)
      {  v = G->v[i];
         for (a = v->out; a != NULL; a = a->t_next)
         {  if (a_low >= 0)
               memcpy(&low, (char *)a->data + a_low, sizeof(double));
            else
               low = 0.0;
            if (a_cap >= 0)
               memcpy(&cap, (char *)a->data + a_cap, sizeof(double));
            else
               cap = 1.0;
            if (a_cost >= 0)
               memcpy(&cost, (char *)a->data + a_cost, sizeof(double));
            else
               cost = 0.0;
            xfprintf(fp, "a %d %d %.*g %.*g %.*g\n",
               a->tail->i, a->head->i, DBL_DIG, low, DBL_DIG, cap,
               DBL_DIG, cost), count++;
         }
      }
      xfprintf(fp, "c eof\n"), count++;
      xfflush(fp);
      if (xferror(fp))
      {  xprintf("Write error on `%s' - %s\n", fname, xerrmsg());
         ret = 1;
         goto done;
      }
      xprintf("%d lines were written\n", count);
      ret = 0;
done: if (fp != NULL) xfclose(fp);
      return ret;
}

/***********************************************************************
*  NAME
*
*  glp_read_maxflow - read maximum flow problem data in DIMACS format
*
*  SYNOPSIS
*
*  int glp_read_maxflow(glp_graph *G, int *s, int *t, int a_cap,
*     const char *fname);
*
*  DESCRIPTION
*
*  The routine glp_read_maxflow reads maximum 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_maxflow(glp_graph *G, int *_s, int *_t, int a_cap,
      const char *fname)
{     struct csa _csa, *csa = &_csa;
      glp_arc *a;
      int i, j, k, s, t, nv, na, ret = 0;
      double cap;
      if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double))
         xerror("glp_read_maxflow: a_cap = %d; invalid offset\n",
            a_cap);
      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 maximum 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, "max") != 0)
         error(csa, "wrong problem designator; `max' expected");
      read_field(csa);
      if (!(str2int(csa->field, &nv) == 0 && nv >= 2))
         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 */
      s = t = 0;
      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);
         read_field(csa);
         if (strcmp(csa->field, "s") == 0)
         {  if (s > 0)
               error(csa, "only one source node allowed");
            s = i;
         }
         else if (strcmp(csa->field, "t") == 0)
         {  if (t > 0)
               error(csa, "only one sink node allowed");
            t = i;
         }
         else
            error(csa, "wrong node designator; `s' or `t' expected");
         if (s > 0 && s == t)
            error(csa, "source and sink nodes must be distinct");
         end_of_line(csa);
      }
      if (s == 0)
         error(csa, "source node descriptor missing\n");
      if (t == 0)
         error(csa, "sink node descriptor missing\n");
      if (_s != NULL) *_s = s;
      if (_t != NULL) *_t = t;
      /* 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, &cap) == 0 && cap >= 0.0))
            error(csa, "arc capacity missing or invalid");
         check_int(csa, cap);
         a = glp_add_arc(G, i, j);
         if (a_cap >= 0)
            memcpy((char *)a->data + a_cap, &cap, sizeof(double));
         end_of_line(csa);
      }
      xprintf("%d lines were read\n", csa->count);
done: if (ret) glp_erase_graph(G, G->v_size, G->a_size);
      if (csa->fp != NULL) xfclose(csa->fp);
      return ret;
}

/***********************************************************************
*  NAME
*
*  glp_write_maxflow - write maximum flow problem data in DIMACS format
*
*  SYNOPSIS
*
*  int glp_write_maxflow(glp_graph *G, int s, int t, int a_cap,
*     const char *fname);
*
*  DESCRIPTION
*
*  The routine glp_write_maxflow writes maximum flow problem data in
*  DIMACS format to 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_write_maxflow(glp_graph *G, int s, int t, int a_cap,
      const char *fname)
{     XFILE *fp;
      glp_vertex *v;
      glp_arc *a;
      int i, count = 0, ret;
      double cap;
      if (!(1 <= s && s <= G->nv))
         xerror("glp_write_maxflow: s = %d; source node number out of r"
            "ange\n", s);
      if (!(1 <= t && t <= G->nv))
         xerror("glp_write_maxflow: t = %d: sink node number out of ran"
            "ge\n", t);
      if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double))
         xerror("glp_write_mincost: a_cap = %d; invalid offset\n",
            a_cap);
      xprintf("Writing maximum flow problem data to `%s'...\n",
         fname);
      fp = xfopen(fname, "w");
      if (fp == NULL)
      {  xprintf("Unable to create `%s' - %s\n", fname, xerrmsg());
         ret = 1;
         goto done;
      }
      xfprintf(fp, "c %s\n",
         G->name == NULL ? "unknown" : G->name), count++;
      xfprintf(fp, "p max %d %d\n", G->nv, G->na), count++;
      xfprintf(fp, "n %d s\n", s), count++;
      xfprintf(fp, "n %d t\n", t), count++;
      for (i = 1; i <= G->nv; i++)
      {  v = G->v[i];
         for (a = v->out; a != NULL; a = a->t_next)
         {  if (a_cap >= 0)
               memcpy(&cap, (char *)a->data + a_cap, sizeof(double));
            else
               cap = 1.0;
            xfprintf(fp, "a %d %d %.*g\n",
               a->tail->i, a->head->i, DBL_DIG, cap), count++;
         }
      }
      xfprintf(fp, "c eof\n"), count++;
      xfflush(fp);
      if (xferror(fp))
      {  xprintf("Write error on `%s' - %s\n", fname, xerrmsg());
         ret = 1;
         goto done;
      }
      xprintf("%d lines were written\n", count);
      ret = 0;
done: if (fp != NULL) xfclose(fp);
      return ret;
}

/* eof */