Fix bug 22419

[pspp-builds.git] / src / math / linreg / predict.c

diff --git a/src/math/linreg/predict.c b/src/math/linreg/predict.c
index f2539c0e1c2d9ae4fab3f470adfe49b157ba4c67..8eba054a83faee575416447c2feb83a4e087c7f2 100644 (file)
--- a/src/math/linreg/predict.c
+++ b/src/math/linreg/predict.c
@@ -1,27 +1,44 @@
-/* lib/linreg/predict.c
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2005 Free Software Foundation, Inc. 
 
- Copyright (C) 2005 Free Software Foundation, Inc.
- Written by Jason H. Stover.
+   This program 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.
 
- This program 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 2 of the License, or (at
- your option) any later version.
+   This program 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.
 
- This program 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 this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02111-1307, USA.
-*/
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
+#include <config.h>
 #include <math/linreg/linreg.h>
-#include <math/linreg/coefficient.h>
+#include <math/coefficient.h>
+#include <gl/xalloc.h>
 
+/*
+  Is the coefficient COEF contained in the list of coefficients
+  COEF_LIST?
+ */
+static int
+has_coefficient (const struct pspp_coeff **coef_list, const struct pspp_coeff *coef,
+                size_t n)
+{
+  size_t i = 0;
+
+  while (i < n)
+    {
+      if (coef_list[i] == coef)
+       {
+         return 1;
+       }
+      i++;
+    }
+  return 0;
+}
 /*
   Predict the value of the dependent variable with the
   new set of predictors. PREDICTORS must point to a list
@@ -29,34 +46,68 @@
   in the same order.
  */
 double
-pspp_linreg_predict (const struct variable *predictors, 
-                    const union value *vals, 
-                    const pspp_linreg_cache *c,
-                    int n_vals)
+pspp_linreg_predict (const struct variable **predictors,
+                    const union value **vals, const void *c_, int n_vals)
 {
-  int i;
+  const pspp_linreg_cache *c = c_;
+  int j;
+  size_t next_coef = 1;
+  const struct pspp_coeff **coef_list;
+  const struct pspp_coeff *coe;
   double result;
   double tmp;
-  
-  assert (predictors != NULL);
-  assert (vals != NULL);
-  assert (c != NULL);
 
-  result = c->coeff->estimate; /* Intercept. */
+  if (predictors == NULL || vals == NULL || c == NULL)
+    {
+      return GSL_NAN;
+    }
+  if (c->coeff == NULL)
+    {
+      /* The stupid model: just guess the mean. */
+      return c->depvar_mean;
+    }
+  coef_list = xnmalloc (c->n_coeffs, sizeof (*coef_list));
+  *coef_list = c->coeff[0];
+  result = c->coeff[0]->estimate;      /* Intercept. */
 
   /*
-    Stop at the minimum of c->n_coeffs and n_vals in case
-    the caller passed us inadequate information, such as too
-    few or too many values.
+     The loops guard against the possibility that the caller passed us
+     inadequate information, such as too few or too many values, or
+     a redundant list of variable names.
    */
-  for (i = 1; i < c->n_coeffs && i < n_vals; i++)
+  for (j = 0; j < n_vals; j++)
     {
-      tmp = pspp_linreg_coeff_get_est (pspp_linreg_get_coeff (c, predictors + i, vals + i));
-      if ((predictors + i)->type == NUMERIC)
+      coe = pspp_linreg_get_coeff (c, predictors[j], vals[j]);
+      if (!has_coefficient (coef_list, coe, next_coef))
        {
-         tmp *= (vals + i)->f;
+         tmp = pspp_coeff_get_est (coe);
+         if (var_is_numeric (predictors[j]))
+           {
+             tmp *= vals[j]->f;
+           }
+         result += tmp;
+         coef_list[next_coef++] = coe;
        }
-      result += tmp;
     }
+  free (coef_list);
+
+  return result;
+}
+
+double
+pspp_linreg_residual (const struct variable **predictors,
+                     const union value **vals,
+                     const union value *obs, const void *c, int n_vals)
+{
+  double pred;
+  double result;
+
+  if (predictors == NULL || vals == NULL || c == NULL || obs == NULL)
+    {
+      return GSL_NAN;
+    }
+  pred = pspp_linreg_predict (predictors, vals, c, n_vals);
+
+  result = gsl_isnan (pred) ? GSL_NAN : (obs->f - pred);
   return result;
 }