[gnumeric] glpk: recover sensitivity information when requested

[Morten Welinder <mortenw src gnome org>]

commit a869e6a5e81c8e95b0cbb04d06c6d45086d58eb3
Author: Morten Welinder <terra gnome org>
Date:   Thu Feb 11 22:23:04 2016 -0500

    glpk: recover sensitivity information when requested

 plugins/glpk/gnm-glpk.c |  170 +++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 158 insertions(+), 12 deletions(-)
---
diff --git a/plugins/glpk/gnm-glpk.c b/plugins/glpk/gnm-glpk.c
index 53d9195..1ca7d8d 100644
--- a/plugins/glpk/gnm-glpk.c
+++ b/plugins/glpk/gnm-glpk.c
@@ -22,6 +22,7 @@
 typedef struct {
        GnmSubSolver *parent;
        char *result_filename;
+       char *ranges_filename;
 } GnmGlpk;
 
 static void
@@ -33,6 +34,11 @@ gnm_glpk_cleanup (GnmGlpk *lp)
                g_free (lp->result_filename);
                lp->result_filename = NULL;
        }
+       if (lp->ranges_filename) {
+               g_unlink (lp->ranges_filename);
+               g_free (lp->ranges_filename);
+               lp->ranges_filename = NULL;
+       }
 }
 
 static void
@@ -61,21 +67,56 @@ write_program (GnmSolver *sol, WorkbookControl *wbc, GError **err)
                                  err);
 }
 
+static char **
+my_strsplit (const char *line)
+{
+       GPtrArray *res = g_ptr_array_new ();
+
+       while (1) {
+               const char *end;
+
+               while (g_ascii_isspace (*line))
+                       line++;
+
+               if (!*line)
+                       break;
+
+               end = line;
+               while (*end && !g_ascii_isspace (*end))
+                       end++;
+
+               g_ptr_array_add (res, g_strndup (line, end - line));
+               line = end;
+       }
+       g_ptr_array_add (res, NULL);
+
+       return (char **)g_ptr_array_free (res, FALSE);
+}
+
+static gnm_float
+parse_number (const char *s)
+{
+       if (strcmp (s, ".") == 0)
+               return 0;
+       return g_ascii_strtod (s, NULL);
+}
+
 static void
 gnm_glpk_read_solution (GnmGlpk *lp)
 {
        GnmSubSolver *subsol = lp->parent;
        GnmSolver *sol = GNM_SOLVER (subsol);
        GsfInput *input;
-       GsfInputTextline *tl;
+       GsfInputTextline *tl = NULL;
        const char *line;
        unsigned rows, cols, c, r;
        int pstat, dstat;
        gnm_float val;
-       GnmSolverResult *result;
-       GnmSolverSensitivity *sensitivity;
+       GnmSolverResult *result = NULL;
+       GnmSolverSensitivity *sensitivity = NULL;
        gboolean has_integer;
        GSList *l;
+       enum { SEC_UNKNOWN, SEC_ROWS, SEC_COLUMNS } state;
 
        /*
         * glpsol's output format is different if there are any integer
@@ -90,8 +131,7 @@ gnm_glpk_read_solution (GnmGlpk *lp)
 
        input = gsf_input_stdio_new (lp->result_filename, NULL);
        if (!input)
-               return;
-
+               goto fail;
        tl = GSF_INPUT_TEXTLINE (gsf_input_textline_new (input));
        g_object_unref (input);
 
@@ -132,10 +172,22 @@ gnm_glpk_read_solution (GnmGlpk *lp)
                goto fail;
        }
 
-       for (r = 1; r <= rows; r++) {
+       for (r = 0; r < rows; r++) {
+               gnm_float pval, dval;
+               unsigned rstat;
+               unsigned cidx = r;
+
                if ((line = gsf_input_textline_utf8_gets (tl)) == NULL)
                        goto fail;
-               /* Ignore the line */
+
+               if (has_integer)
+                       continue;
+
+               if (sscanf (line, "%u %" GNM_SCANF_g " %" GNM_SCANF_g,
+                           &rstat, &pval, &dval) != 3)
+                       goto fail;
+
+               sensitivity->constraints[cidx].shadow_price = dval;
        }
 
        for (c = 0; c < cols; c++) {
@@ -157,18 +209,99 @@ gnm_glpk_read_solution (GnmGlpk *lp)
                        sensitivity->vars[idx].reduced_cost = dval;
        }
 
+       g_object_unref (tl);
+       tl = NULL;
+
+       // ----------------------------------------
+
+       if (!lp->ranges_filename)
+               goto done;
+
+       input = gsf_input_stdio_new (lp->ranges_filename, NULL);
+       if (!input)
+               goto fail;
+       tl = GSF_INPUT_TEXTLINE (gsf_input_textline_new (input));
+       g_object_unref (input);
+
+       state = SEC_UNKNOWN;
+       // We are reading a file intended for human consumption.
+       // That is unfortunately because it implies rounding, for example.
+       // The information does not appear to be available elsewhere.
+
+       while ((line = gsf_input_textline_utf8_gets (tl)) != NULL) {
+               gchar **items, **items2 = NULL;
+               int len, len2 = 0;
+
+               if (g_str_has_prefix (line, "   No. Row name")) {
+                       state = SEC_ROWS;
+                       continue;
+               } else if (g_str_has_prefix (line, "   No. Column name")) {
+                       state = SEC_COLUMNS;
+                       continue;
+               } else if (g_ascii_isalpha (line[0])) {
+                       state = SEC_UNKNOWN;
+                       continue;
+               }
+
+               if (state == SEC_UNKNOWN)
+                       continue;
+
+               items = my_strsplit (line);
+               len = g_strv_length (items);
+
+               if (len == 10 && g_ascii_isdigit (items[0][0])) {
+                       line = gsf_input_textline_utf8_gets (tl);
+                       if (line) {
+                               items2 = my_strsplit (line);
+                               len2 = g_strv_length (items2);
+                       }
+               }
+
+               if (len == 10 && len2 == 6 && state == SEC_COLUMNS) {
+                       gnm_float low = parse_number (items[7]);
+                       gnm_float high = parse_number (items2[3]);
+                       GnmCell const *cell = gnm_sub_solver_find_cell (lp->parent, items[1]);
+                       int idx = gnm_solver_cell_index (sol, cell);
+                       if (idx >= 0) {
+                               sensitivity->vars[idx].low = low;
+                               sensitivity->vars[idx].high = high;
+                       }
+               }
+
+               if (len == 10 && len2 == 6 && state == SEC_ROWS) {
+                       gnm_float low = parse_number (items[6]);
+                       gnm_float high = parse_number (items2[2]);
+                       int cidx = gnm_sub_solver_find_constraint (lp->parent, items[1]);
+                       if (cidx >= 0) {
+                               sensitivity->constraints[cidx].low = low;
+                               sensitivity->constraints[cidx].high = high;
+                       }
+               }
+               
+               g_strfreev (items);
+               g_strfreev (items2);
+
+       }
+
+       g_object_unref (tl);
+
+       // ----------------------------------------
+done:
        gnm_solver_set_status (sol, GNM_SOLVER_STATUS_DONE);
        g_object_set (subsol, "result", result, NULL);
        g_object_unref (result);
        g_object_set (subsol, "sensitivity", sensitivity, NULL);
        g_object_unref (sensitivity);
 
-       g_object_unref (tl);
        return;
 
 fail:
-       g_object_unref (tl);
-       g_object_unref (result);
+       if (tl)
+               g_object_unref (tl);
+       if (result)
+               g_object_unref (result);
+       if (sensitivity)
+               g_object_unref (sensitivity);
        gnm_solver_set_status (sol, GNM_SOLVER_STATUS_ERROR);
 }
 
@@ -238,9 +371,18 @@ gnm_glpk_prepare (GnmSolver *sol, WorkbookControl *wbc, GError **err,
                             _("Failed to create file for solution"));
                goto fail;
        }
-
        close (fd);
 
+       if (sol->params->options.sensitivity_report) {
+               fd = g_file_open_tmp ("program-XXXXXX.ran", &lp->ranges_filename, err);
+               if (fd == -1) {
+                       g_set_error (err, G_FILE_ERROR, 0,
+                                    _("Failed to create file for sensitivity report"));
+                       goto fail;
+               }
+               close (fd);
+       }
+
        gnm_solver_set_status (sol, GNM_SOLVER_STATUS_PREPARED);
 
        return TRUE;
@@ -257,7 +399,7 @@ gnm_glpk_start (GnmSolver *sol, WorkbookControl *wbc, GError **err,
 {
        GnmSubSolver *subsol = GNM_SUB_SOLVER (sol);
        gboolean ok;
-       gchar *argv[7];
+       gchar *argv[9];
        int argc = 0;
        GnmSolverParameters *param = sol->params;
        const char *binary;
@@ -274,6 +416,10 @@ gnm_glpk_start (GnmSolver *sol, WorkbookControl *wbc, GError **err,
                                 : "--noscale");
        argv[argc++] = (gchar *)"--write";
        argv[argc++] = lp->result_filename;
+       if (lp->ranges_filename) {
+               argv[argc++] = (gchar *)"--ranges";
+               argv[argc++] = lp->ranges_filename;
+       }
        argv[argc++] = (gchar *)"--cpxlp";
        argv[argc++] = subsol->program_filename;
        argv[argc] = NULL;