partial fix of bug 19819

diff --git a/src/language/stats/ChangeLog b/src/language/stats/ChangeLog
index db148a4ffe397c7f1c06fc88e4dbaaa6e0d1efe0..c55b8fb0a17625db7bb9ef486ccf7b08abd55ad9 100644 (file)
--- a/src/language/stats/ChangeLog
+++ b/src/language/stats/ChangeLog
@@ -1,3 +1,8 @@
+2007-05-08  Jason Stover  <jhs@math.gcsu.edu>
+
+       * regression.q: Partial fix of bug which caused a crash if
+       dependent variable and independent variable were the same.
+
 2007-04-16 John Darrington <john@darrington.wattle.id.au>
 
        * t-test.q: Changed the output width of reported counts and 

diff --git a/src/language/stats/regression.q b/src/language/stats/regression.q
index e38167900c4edfba0486c742fab18f8acdd6a22a..37b3b48dd214444468d92ae31070123b70bde5f8 100644 (file)
--- a/src/language/stats/regression.q
+++ b/src/language/stats/regression.q
@@ -1066,7 +1066,7 @@ get_n_indep (const struct variable *v)
        }
       i++;
     }
-  return result;
+  return (result == 0) ? 1 : result;
 }
 
 /*
@@ -1087,7 +1087,12 @@ prepare_data (int n_data, int is_missing_case[],
   j = 0;
   for (i = 0; i < n_variables; i++)
     {
-      if (!is_depvar (i, depvar))
+      /*
+       The second condition ensures the program will run even if
+       there is only one variable to act as both explanatory and
+       response.
+       */
+      if ((!is_depvar (i, depvar)) || (n_variables == 1))
        {
          indep_vars[j] = v_variables[i];
          j++;
@@ -1221,11 +1226,12 @@ run_regression (const struct ccase *first,
       n_data = prepare_data (n_cases, is_missing_case, indep_vars,
                             cmd.v_dependent[k],
                             (const struct casefile *) cf, mom);
-      if (n_data > 0)
+      if ((n_data > 0) && (n_indep > 0))
        {
          Y = gsl_vector_alloc (n_data);
          X =
-           design_matrix_create (n_indep, (const struct variable **) indep_vars,
+           design_matrix_create (n_indep,
+                                 (const struct variable **) indep_vars,
                                  n_data);
          for (i = 0; i < X->m->size2; i++)
            {
@@ -1236,16 +1242,16 @@ run_regression (const struct ccase *first,
          models[k]->indep_std = gsl_vector_alloc (X->m->size2);
          models[k]->depvar = (const struct variable *) cmd.v_dependent[k];
          /*
-           For large data sets, use QR decomposition.
-         */
+            For large data sets, use QR decomposition.
+          */
          if (n_data > sqrt (n_indep) && n_data > REG_LARGE_DATA)
            {
              models[k]->method = PSPP_LINREG_SVD;
            }
-         
+
          /*
-           The second pass fills the design matrix.
-         */
+            The second pass fills the design matrix.
+          */
          row = 0;
          for (r = casefile_get_reader (cf, NULL); casereader_read (r, &c);
               case_destroy (&c))
@@ -1257,28 +1263,29 @@ run_regression (const struct ccase *first,
                  for (i = 0; i < n_variables; ++i)     /* Iterate over the
                                                           variables for the
                                                           current case.
-                                                       */
+                                                        */
                    {
                      val = case_data (&c, v_variables[i]);
                      /*
-                       Independent/dependent variable separation. The
-                       'variables' subcommand specifies a varlist which contains
-                       both dependent and independent variables. The dependent
-                       variables are specified with the 'dependent'
-                       subcommand, and maybe also in the 'variables' subcommand. 
-                       We need to separate the two.
-                     */
+                        Independent/dependent variable separation. The
+                        'variables' subcommand specifies a varlist which contains
+                        both dependent and independent variables. The dependent
+                        variables are specified with the 'dependent'
+                        subcommand, and maybe also in the 'variables' subcommand. 
+                        We need to separate the two.
+                      */
                      if (!is_depvar (i, cmd.v_dependent[k]))
                        {
                          if (var_is_alpha (v_variables[i]))
                            {
                              design_matrix_set_categorical (X, row,
-                                                            v_variables[i], val);
+                                                            v_variables[i],
+                                                            val);
                            }
                          else
                            {
-                             design_matrix_set_numeric (X, row, v_variables[i],
-                                                        val);
+                             design_matrix_set_numeric (X, row,
+                                                        v_variables[i], val);
                            }
                        }
                    }
@@ -1288,20 +1295,20 @@ run_regression (const struct ccase *first,
                }
            }
          /*
-           Now that we know the number of coefficients, allocate space
-           and store pointers to the variables that correspond to the
-           coefficients.
-         */
+            Now that we know the number of coefficients, allocate space
+            and store pointers to the variables that correspond to the
+            coefficients.
+          */
          coeff_init (models[k], X);
-         
+
          /* 
             Find the least-squares estimates and other statistics.
-         */
+          */
          pspp_linreg ((const gsl_vector *) Y, X->m, &lopts, models[k]);
          compute_moments (models[k], mom, X, n_variables);
          subcommand_statistics (cmd.a_statistics, models[k]);
          subcommand_export (cmd.sbc_export, models[k]);
-         
+
          gsl_vector_free (Y);
          design_matrix_destroy (X);
          free (indep_vars);