diff -r d59bea55db9b -r c445c931472f src/glptsp.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/glptsp.c	Mon Dec 06 13:09:21 2010 +0100
@@ -0,0 +1,667 @@
+/* glptsp.c */
+
+/***********************************************************************
+*  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/>.
+***********************************************************************/
+
+#define _GLPSTD_ERRNO
+#define _GLPSTD_STDIO
+#include "glpenv.h"
+#include "glptsp.h"
+#define xfault xerror
+
+/*----------------------------------------------------------------------
+-- tsp_read_data - read TSP instance data.
+--
+-- *Synopsis*
+--
+-- #include "glptsp.h"
+-- TSP *tsp_read_data(char *fname);
+--
+-- *Description*
+--
+-- The routine tsp_read_data reads a TSP (or related problem) instance
+-- data from the text file, whose name is the character string fname.
+--
+-- For detailed description of the format recognized by the routine see
+-- the report: G.Reinelt, TSPLIB 95.
+--
+-- *Returns*
+--
+-- If no error occurred, the routine tsp_read_data returns a pointer to
+-- the TSP instance data block, which contains loaded data. In the case
+-- of error the routine prints an error message and returns NULL. */
+
+struct dsa
+{     /* dynamic storage area used by the routine tsp_read_data */
+      char *fname;
+      /* name of the input text file */
+      FILE *fp;
+      /* stream assigned to the input text file */
+      int seqn;
+      /* line sequential number */
+      int c;
+      /* current character */
+      char token[255+1];
+      /* current token */
+};
+
+static int get_char(struct dsa *dsa)
+{     dsa->c = fgetc(dsa->fp);
+      if (ferror(dsa->fp))
+      {  xprintf("%s:%d: read error - %s\n",
+            dsa->fname, dsa->seqn, strerror(errno));
+         return 1;
+      }
+      if (feof(dsa->fp))
+         dsa->c = EOF;
+      else if (dsa->c == '\n')
+         dsa->seqn++;
+      else if (isspace(dsa->c))
+         dsa->c = ' ';
+      else if (iscntrl(dsa->c))
+      {  xprintf("%s:%d: invalid control character 0x%02X\n",
+            dsa->fname, dsa->seqn, dsa->c);
+         return 1;
+      }
+      return 0;
+}
+
+static int skip_spaces(struct dsa *dsa, int across)
+{     while (dsa->c == ' ' || (across && dsa->c == '\n'))
+         if (get_char(dsa)) return 1;
+      return 0;
+}
+
+static int scan_keyword(struct dsa *dsa)
+{     int len = 0;
+      if (skip_spaces(dsa, 0)) return 1;
+      dsa->token[0] = '\0';
+      while (isalnum(dsa->c) || dsa->c == '_')
+      {  if (len == 31)
+         {  xprintf("%s:%d: keyword `%s...' too long\n", dsa->fname,
+               dsa->seqn, dsa->token);
+            return 1;
+         }
+         dsa->token[len++] = (char)dsa->c, dsa->token[len] = '\0';
+         if (get_char(dsa)) return 1;
+      }
+      if (len == 0)
+      {  xprintf("%s:%d: missing keyword\n", dsa->fname, dsa->seqn);
+         return 1;
+      }
+      return 0;
+}
+
+static int check_colon(struct dsa *dsa)
+{     if (skip_spaces(dsa, 0)) return 1;
+      if (dsa->c != ':')
+      {  xprintf("%s:%d: missing colon after `%s'\n", dsa->fname,
+            dsa->seqn, dsa->token);
+         return 1;
+      }
+      if (get_char(dsa)) return 1;
+      return 0;
+}
+
+static int scan_token(struct dsa *dsa, int across)
+{     int len = 0;
+      if (skip_spaces(dsa, across)) return 1;
+      dsa->token[0] = '\0';
+      while (!(dsa->c == EOF || dsa->c == '\n' || dsa->c == ' '))
+      {  if (len == 255)
+         {  dsa->token[31] = '\0';
+            xprintf("%s:%d: token `%s...' too long\n", dsa->fname,
+               dsa->seqn, dsa->token);
+            return 1;
+         }
+         dsa->token[len++] = (char)dsa->c, dsa->token[len] = '\0';
+         if (get_char(dsa)) return 1;
+      }
+      return 0;
+}
+
+static int check_newline(struct dsa *dsa)
+{     if (skip_spaces(dsa, 0)) return 1;
+      if (!(dsa->c == EOF || dsa->c == '\n'))
+      {  xprintf("%s:%d: extra symbols detected\n", dsa->fname,
+            dsa->seqn);
+         return 1;
+      }
+      if (get_char(dsa)) return 1;
+      return 0;
+}
+
+static int scan_comment(struct dsa *dsa)
+{     int len = 0;
+      if (skip_spaces(dsa, 0)) return 1;
+      dsa->token[0] = '\0';
+      while (!(dsa->c == EOF || dsa->c == '\n'))
+      {  if (len == 255)
+         {  xprintf("%s:%d: comment too long\n", dsa->fname, dsa->seqn)
+               ;
+            return 1;
+         }
+         dsa->token[len++] = (char)dsa->c, dsa->token[len] = '\0';
+         if (get_char(dsa)) return 1;
+      }
+      return 0;
+}
+
+static int scan_integer(struct dsa *dsa, int across, int *val)
+{     if (scan_token(dsa, across)) return 1;
+      if (strlen(dsa->token) == 0)
+      {  xprintf("%s:%d: missing integer\n", dsa->fname, dsa->seqn);
+         return 1;
+      }
+      if (str2int(dsa->token, val))
+      {  xprintf("%s:%d: integer `%s' invalid\n", dsa->fname, dsa->seqn
+            , dsa->token);
+         return 1;
+      }
+      return 0;
+}
+
+static int scan_number(struct dsa *dsa, int across, double *val)
+{     if (scan_token(dsa, across)) return 1;
+      if (strlen(dsa->token) == 0)
+      {  xprintf("%s:%d: missing number\n", dsa->fname, dsa->seqn);
+         return 1;
+      }
+      if (str2num(dsa->token, val))
+      {  xprintf("%s:%d: number `%s' invalid\n", dsa->fname, dsa->seqn,
+            dsa->token);
+         return 1;
+      }
+      return 0;
+}
+
+TSP *tsp_read_data(char *fname)
+{     struct dsa _dsa, *dsa = &_dsa;
+      TSP *tsp = NULL;
+      dsa->fname = fname;
+      xprintf("tsp_read_data: reading TSP data from `%s'...\n",
+         dsa->fname);
+      dsa->fp = fopen(dsa->fname, "r");
+      if (dsa->fp == NULL)
+      {  xprintf("tsp_read_data: unable to open `%s' - %s\n",
+            dsa->fname, strerror(errno));
+         goto fail;
+      }
+      tsp = xmalloc(sizeof(TSP));
+      tsp->name = NULL;
+      tsp->type = TSP_UNDEF;
+      tsp->comment = NULL;
+      tsp->dimension = 0;
+      tsp->edge_weight_type = TSP_UNDEF;
+      tsp->edge_weight_format = TSP_UNDEF;
+      tsp->display_data_type = TSP_UNDEF;
+      tsp->node_x_coord = NULL;
+      tsp->node_y_coord = NULL;
+      tsp->dply_x_coord = NULL;
+      tsp->dply_y_coord = NULL;
+      tsp->tour = NULL;
+      tsp->edge_weight = NULL;
+      dsa->seqn = 1;
+      if (get_char(dsa)) goto fail;
+loop: if (scan_keyword(dsa)) goto fail;
+      if (strcmp(dsa->token, "NAME") == 0)
+      {  if (tsp->name != NULL)
+         {  xprintf("%s:%d: NAME entry multiply defined\n", dsa->fname,
+               dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_token(dsa, 0)) goto fail;
+         if (strlen(dsa->token) == 0)
+         {  xprintf("%s:%d: NAME entry incomplete\n", dsa->fname,
+               dsa->seqn);
+            goto fail;
+         }
+         tsp->name = xmalloc(strlen(dsa->token) + 1);
+         strcpy(tsp->name, dsa->token);
+         xprintf("tsp_read_data: NAME: %s\n", tsp->name);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "TYPE") == 0)
+      {  if (tsp->type != TSP_UNDEF)
+         {  xprintf("%s:%d: TYPE entry multiply defined\n", dsa->fname,
+               dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_keyword(dsa)) goto fail;
+         if (strcmp(dsa->token, "TSP") == 0)
+            tsp->type = TSP_TSP;
+         else if (strcmp(dsa->token, "ATSP") == 0)
+            tsp->type = TSP_ATSP;
+         else if (strcmp(dsa->token, "TOUR") == 0)
+            tsp->type = TSP_TOUR;
+         else
+         {  xprintf("%s:%d: data type `%s' not recognized\n",
+               dsa->fname, dsa->seqn, dsa->token);
+            goto fail;
+         }
+         xprintf("tsp_read_data: TYPE: %s\n", dsa->token);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "COMMENT") == 0)
+      {  if (tsp->comment != NULL)
+         {  xprintf("%s:%d: COMMENT entry multiply defined\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_comment(dsa)) goto fail;
+         tsp->comment = xmalloc(strlen(dsa->token) + 1);
+         strcpy(tsp->comment, dsa->token);
+         xprintf("tsp_read_data: COMMENT: %s\n", tsp->comment);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "DIMENSION") == 0)
+      {  if (tsp->dimension != 0)
+         {  xprintf("%s:%d: DIMENSION entry multiply defined\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_integer(dsa, 0, &tsp->dimension)) goto fail;
+         if (tsp->dimension < 1)
+         {  xprintf("%s:%d: invalid dimension\n", dsa->fname,
+               dsa->seqn);
+            goto fail;
+         }
+         xprintf("tsp_read_data: DIMENSION: %d\n", tsp->dimension);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "EDGE_WEIGHT_TYPE") == 0)
+      {  if (tsp->edge_weight_type != TSP_UNDEF)
+         {  xprintf("%s:%d: EDGE_WEIGHT_TYPE entry multiply defined\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_keyword(dsa)) goto fail;
+         if (strcmp(dsa->token, "GEO") == 0)
+            tsp->edge_weight_type = TSP_GEO;
+         else if (strcmp(dsa->token, "EUC_2D") == 0)
+            tsp->edge_weight_type = TSP_EUC_2D;
+         else if (strcmp(dsa->token, "ATT") == 0)
+            tsp->edge_weight_type = TSP_ATT;
+         else if (strcmp(dsa->token, "EXPLICIT") == 0)
+            tsp->edge_weight_type = TSP_EXPLICIT;
+         else if (strcmp(dsa->token, "CEIL_2D") == 0)
+            tsp->edge_weight_type = TSP_CEIL_2D;
+         else
+         {  xprintf("%s:%d: edge weight type `%s' not recognized\n",
+               dsa->fname, dsa->seqn, dsa->token);
+            goto fail;
+         }
+         xprintf("tsp_read_data: EDGE_WEIGHT_TYPE: %s\n", dsa->token);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "EDGE_WEIGHT_FORMAT") == 0)
+      {  if (tsp->edge_weight_format != TSP_UNDEF)
+         {  xprintf(
+               "%s:%d: EDGE_WEIGHT_FORMAT entry multiply defined\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_keyword(dsa)) goto fail;
+         if (strcmp(dsa->token, "UPPER_ROW") == 0)
+            tsp->edge_weight_format = TSP_UPPER_ROW;
+         else if (strcmp(dsa->token, "FULL_MATRIX") == 0)
+            tsp->edge_weight_format = TSP_FULL_MATRIX;
+         else if (strcmp(dsa->token, "FUNCTION") == 0)
+            tsp->edge_weight_format = TSP_FUNCTION;
+         else if (strcmp(dsa->token, "LOWER_DIAG_ROW") == 0)
+            tsp->edge_weight_format = TSP_LOWER_DIAG_ROW;
+         else
+         {  xprintf("%s:%d: edge weight format `%s' not recognized\n",
+               dsa->fname, dsa->seqn, dsa->token);
+            goto fail;
+         }
+         xprintf("tsp_read_data: EDGE_WEIGHT_FORMAT: %s\n", dsa->token);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "DISPLAY_DATA_TYPE") == 0)
+      {  if (tsp->display_data_type != TSP_UNDEF)
+         {  xprintf("%s:%d: DISPLAY_DATA_TYPE entry multiply defined\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_colon(dsa)) goto fail;
+         if (scan_keyword(dsa)) goto fail;
+         if (strcmp(dsa->token, "COORD_DISPLAY") == 0)
+            tsp->display_data_type = TSP_COORD_DISPLAY;
+         else if (strcmp(dsa->token, "TWOD_DISPLAY") == 0)
+            tsp->display_data_type = TSP_TWOD_DISPLAY;
+         else
+         {  xprintf("%s:%d: display data type `%s' not recognized\n",
+               dsa->fname, dsa->seqn, dsa->token);
+            goto fail;
+         }
+         xprintf("tsp_read_data: DISPLAY_DATA_TYPE: %s\n", dsa->token);
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "NODE_COORD_SECTION") == 0)
+      {  int n = tsp->dimension, k, node;
+         if (n == 0)
+         {  xprintf("%s:%d: DIMENSION entry not specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (tsp->node_x_coord != NULL)
+         {  xprintf("%s:%d: NODE_COORD_SECTION multiply specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+         tsp->node_x_coord = xcalloc(1+n, sizeof(double));
+         tsp->node_y_coord = xcalloc(1+n, sizeof(double));
+         for (node = 1; node <= n; node++)
+            tsp->node_x_coord[node] = tsp->node_y_coord[node] = DBL_MAX;
+         for (k = 1; k <= n; k++)
+         {  if (scan_integer(dsa, 0, &node)) goto fail;
+            if (!(1 <= node && node <= n))
+            {  xprintf("%s:%d: invalid node number %d\n", dsa->fname,
+                  dsa->seqn, node);
+               goto fail;
+            }
+            if (tsp->node_x_coord[node] != DBL_MAX)
+            {  xprintf("%s:%d: node number %d multiply specified\n",
+                  dsa->fname, dsa->seqn, node);
+               goto fail;
+            }
+            if (scan_number(dsa, 0, &tsp->node_x_coord[node]))
+               goto fail;
+            if (scan_number(dsa, 0, &tsp->node_y_coord[node]))
+               goto fail;
+            if (check_newline(dsa)) goto fail;
+         }
+      }
+      else if (strcmp(dsa->token, "DISPLAY_DATA_SECTION") == 0)
+      {  int n = tsp->dimension, k, node;
+         if (n == 0)
+         {  xprintf("%s:%d: DIMENSION entry not specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (tsp->dply_x_coord != NULL)
+         {  xprintf("%s:%d: DISPLAY_DATA_SECTION multiply specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+         tsp->dply_x_coord = xcalloc(1+n, sizeof(double));
+         tsp->dply_y_coord = xcalloc(1+n, sizeof(double));
+         for (node = 1; node <= n; node++)
+            tsp->dply_x_coord[node] = tsp->dply_y_coord[node] = DBL_MAX;
+         for (k = 1; k <= n; k++)
+         {  if (scan_integer(dsa, 0, &node)) goto fail;
+            if (!(1 <= node && node <= n))
+            {  xprintf("%s:%d: invalid node number %d\n", dsa->fname,
+                  dsa->seqn, node);
+               goto fail;
+            }
+            if (tsp->dply_x_coord[node] != DBL_MAX)
+            {  xprintf("%s:%d: node number %d multiply specified\n",
+                  dsa->fname, dsa->seqn, node);
+               goto fail;
+            }
+            if (scan_number(dsa, 0, &tsp->dply_x_coord[node]))
+               goto fail;
+            if (scan_number(dsa, 0, &tsp->dply_y_coord[node]))
+               goto fail;
+            if (check_newline(dsa)) goto fail;
+         }
+      }
+      else if (strcmp(dsa->token, "TOUR_SECTION") == 0)
+      {  int n = tsp->dimension, k, node;
+         if (n == 0)
+         {  xprintf("%s:%d: DIMENSION entry not specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (tsp->tour != NULL)
+         {  xprintf("%s:%d: TOUR_SECTION multiply specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+         tsp->tour = xcalloc(1+n, sizeof(int));
+         for (k = 1; k <= n; k++)
+         {  if (scan_integer(dsa, 1, &node)) goto fail;
+            if (!(1 <= node && node <= n))
+            {  xprintf("%s:%d: invalid node number %d\n", dsa->fname,
+                  dsa->seqn, node);
+               goto fail;
+            }
+            tsp->tour[k] = node;
+         }
+         if (scan_integer(dsa, 1, &node)) goto fail;
+         if (node != -1)
+         {  xprintf("%s:%d: extra node(s) detected\n", dsa->fname,
+               dsa->seqn);
+            goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "EDGE_WEIGHT_SECTION") == 0)
+      {  int n = tsp->dimension, i, j, temp;
+         if (n == 0)
+         {  xprintf("%s:%d: DIMENSION entry not specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (tsp->edge_weight_format == TSP_UNDEF)
+         {  xprintf("%s:%d: EDGE_WEIGHT_FORMAT entry not specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (tsp->edge_weight != NULL)
+         {  xprintf("%s:%d: EDGE_WEIGHT_SECTION multiply specified\n",
+               dsa->fname, dsa->seqn);
+            goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+         tsp->edge_weight = xcalloc(1+n*n, sizeof(int));
+         switch (tsp->edge_weight_format)
+         {  case TSP_FULL_MATRIX:
+               for (i = 1; i <= n; i++)
+               {  for (j = 1; j <= n; j++)
+                  {  if (scan_integer(dsa, 1, &temp)) goto fail;
+                     tsp->edge_weight[(i - 1) * n + j] = temp;
+                  }
+               }
+               break;
+            case TSP_UPPER_ROW:
+               for (i = 1; i <= n; i++)
+               {  tsp->edge_weight[(i - 1) * n + i] = 0;
+                  for (j = i + 1; j <= n; j++)
+                  {  if (scan_integer(dsa, 1, &temp)) goto fail;
+                     tsp->edge_weight[(i - 1) * n + j] = temp;
+                     tsp->edge_weight[(j - 1) * n + i] = temp;
+                  }
+               }
+               break;
+            case TSP_LOWER_DIAG_ROW:
+               for (i = 1; i <= n; i++)
+               {  for (j = 1; j <= i; j++)
+                  {  if (scan_integer(dsa, 1, &temp)) goto fail;
+                     tsp->edge_weight[(i - 1) * n + j] = temp;
+                     tsp->edge_weight[(j - 1) * n + i] = temp;
+                  }
+               }
+               break;
+            default:
+               goto fail;
+         }
+         if (check_newline(dsa)) goto fail;
+      }
+      else if (strcmp(dsa->token, "EOF") == 0)
+      {  if (check_newline(dsa)) goto fail;
+         goto done;
+      }
+      else
+      {  xprintf("%s:%d: keyword `%s' not recognized\n", dsa->fname,
+            dsa->seqn, dsa->token);
+         goto fail;
+      }
+      goto loop;
+done: xprintf("tsp_read_data: %d lines were read\n", dsa->seqn-1);
+      fclose(dsa->fp);
+      return tsp;
+fail: if (tsp != NULL)
+      {  if (tsp->name != NULL) xfree(tsp->name);
+         if (tsp->comment != NULL) xfree(tsp->comment);
+         if (tsp->node_x_coord != NULL) xfree(tsp->node_x_coord);
+         if (tsp->node_y_coord != NULL) xfree(tsp->node_y_coord);
+         if (tsp->dply_x_coord != NULL) xfree(tsp->dply_x_coord);
+         if (tsp->dply_y_coord != NULL) xfree(tsp->dply_y_coord);
+         if (tsp->tour != NULL) xfree(tsp->tour);
+         if (tsp->edge_weight != NULL) xfree(tsp->edge_weight);
+         xfree(tsp);
+      }
+      if (dsa->fp != NULL) fclose(dsa->fp);
+      return NULL;
+}
+
+/*----------------------------------------------------------------------
+-- tsp_free_data - free TSP instance data.
+--
+-- *Synopsis*
+--
+-- #include "glptsp.h"
+-- void tsp_free_data(TSP *tsp);
+--
+-- *Description*
+--
+-- The routine tsp_free_data frees all the memory allocated to the TSP
+-- instance data block, which the parameter tsp points to. */
+
+void tsp_free_data(TSP *tsp)
+{     if (tsp->name != NULL) xfree(tsp->name);
+      if (tsp->comment != NULL) xfree(tsp->comment);
+      if (tsp->node_x_coord != NULL) xfree(tsp->node_x_coord);
+      if (tsp->node_y_coord != NULL) xfree(tsp->node_y_coord);
+      if (tsp->dply_x_coord != NULL) xfree(tsp->dply_x_coord);
+      if (tsp->dply_y_coord != NULL) xfree(tsp->dply_y_coord);
+      if (tsp->tour != NULL) xfree(tsp->tour);
+      if (tsp->edge_weight != NULL) xfree(tsp->edge_weight);
+      xfree(tsp);
+      return;
+}
+
+/*----------------------------------------------------------------------
+-- tsp_distance - compute distance between two nodes.
+--
+-- *Synopsis*
+--
+-- #include "glptsp.h"
+-- int tsp_distance(TSP *tsp, int i, int j);
+--
+-- *Description*
+--
+-- The routine tsp_distance computes the distance between i-th and j-th
+-- nodes for the TSP instance, which tsp points to.
+--
+-- *Returns*
+--
+-- The routine tsp_distance returns the computed distance. */
+
+#define nint(x) ((int)((x) + 0.5))
+
+static double rad(double x)
+{     /* convert input coordinate to longitude/latitude, in radians */
+      double pi = 3.141592, deg, min;
+      deg = (int)x;
+      min = x - deg;
+      return pi * (deg + 5.0 * min / 3.0) / 180.0;
+}
+
+int tsp_distance(TSP *tsp, int i, int j)
+{     int n = tsp->dimension, dij;
+      if (!(tsp->type == TSP_TSP || tsp->type == TSP_ATSP))
+         xfault("tsp_distance: invalid TSP instance\n");
+      if (!(1 <= i && i <= n && 1 <= j && j <= n))
+         xfault("tsp_distance: node number out of range\n");
+      switch (tsp->edge_weight_type)
+      {  case TSP_UNDEF:
+            xfault("tsp_distance: edge weight type not specified\n");
+         case TSP_EXPLICIT:
+            if (tsp->edge_weight == NULL)
+               xfault("tsp_distance: edge weights not specified\n");
+            dij = tsp->edge_weight[(i - 1) * n + j];
+            break;
+         case TSP_EUC_2D:
+            if (tsp->node_x_coord == NULL || tsp->node_y_coord == NULL)
+               xfault("tsp_distance: node coordinates not specified\n");
+            {  double xd, yd;
+               xd = tsp->node_x_coord[i] - tsp->node_x_coord[j];
+               yd = tsp->node_y_coord[i] - tsp->node_y_coord[j];
+               dij = nint(sqrt(xd * xd + yd * yd));
+            }
+            break;
+         case TSP_CEIL_2D:
+            if (tsp->node_x_coord == NULL || tsp->node_y_coord == NULL)
+               xfault("tsp_distance: node coordinates not specified\n");
+            {  double xd, yd;
+               xd = tsp->node_x_coord[i] - tsp->node_x_coord[j];
+               yd = tsp->node_y_coord[i] - tsp->node_y_coord[j];
+               dij = (int)ceil(sqrt(xd * xd + yd * yd));
+            }
+            break;
+         case TSP_GEO:
+            if (tsp->node_x_coord == NULL || tsp->node_y_coord == NULL)
+               xfault("tsp_distance: node coordinates not specified\n");
+            {  double rrr = 6378.388;
+               double latitude_i = rad(tsp->node_x_coord[i]);
+               double latitude_j = rad(tsp->node_x_coord[j]);
+               double longitude_i = rad(tsp->node_y_coord[i]);
+               double longitude_j = rad(tsp->node_y_coord[j]);
+               double q1 = cos(longitude_i - longitude_j);
+               double q2 = cos(latitude_i - latitude_j);
+               double q3 = cos(latitude_i + latitude_j);
+               dij = (int)(rrr * acos(0.5 * ((1.0 + q1) * q2 -
+                  (1.0 - q1) *q3)) + 1.0);
+            }
+            break;
+         case TSP_ATT:
+            if (tsp->node_x_coord == NULL || tsp->node_y_coord == NULL)
+               xfault("tsp_distance: node coordinates not specified\n");
+            {  int tij;
+               double xd, yd, rij;
+               xd = tsp->node_x_coord[i] - tsp->node_x_coord[j];
+               yd = tsp->node_y_coord[i] - tsp->node_y_coord[j];
+               rij = sqrt((xd * xd + yd * yd) / 10.0);
+               tij = nint(rij);
+               if (tij < rij) dij = tij + 1; else dij = tij;
+            }
+            break;
+         default:
+            xassert(tsp->edge_weight_type != tsp->edge_weight_type);
+      }
+      return dij;
+}
+
+/* eof */