Change many %g format specifiers to %.*g with precision DBL_DIG + 1.

[pspp] / src / language / stats / crosstabs.q

diff --git a/src/language/stats/crosstabs.q b/src/language/stats/crosstabs.q
index 93c28ca7e7e755e999376ca19d0c5cc8e378b61d..bcb5a0ebacc5c546f2ab4127c5f33280b9a60379 100644 (file)
--- a/src/language/stats/crosstabs.q
+++ b/src/language/stats/crosstabs.q
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 1997-9, 2000, 2006, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2006, 2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.
 
    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
@@ -29,6 +29,7 @@
 #include <config.h>
 
 #include <ctype.h>
+#include <float.h>
 #include <gsl/gsl_cdf.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -1944,8 +1945,8 @@ display_risk (struct pivot_table *pt, struct tab_table *risk)
        case 1:
        case 2:
          if (var_is_numeric (rv))
-           sprintf (buf, _("For cohort %s = %g"),
-                    var_to_string (rv), pt->rows[i - 1].f);
+           sprintf (buf, _("For cohort %s = %.*g"),
+                    var_to_string (rv), DBL_DIG + 1, pt->rows[i - 1].f);
          else
            sprintf (buf, _("For cohort %s = %.*s"),
                     var_to_string (rv),
@@ -2090,16 +2091,17 @@ display_directional (struct crosstabs_proc *proc, struct pivot_table *pt,
 \f
 /* Statistical calculations. */
 
-/* Returns the value of the gamma (factorial) function for an integer
+/* Returns the value of the logarithm of gamma (factorial) function for an integer
    argument PT. */
 static double
-gamma_int (double pt)
+log_gamma_int (double pt)
 {
-  double r = 1;
+  double r = 0;
   int i;
 
   for (i = 2; i < pt; i++)
-    r *= i;
+    r += log(i);
+
   return r;
 }
 
@@ -2108,11 +2110,11 @@ gamma_int (double pt)
 static inline double
 Pr (int a, int b, int c, int d)
 {
-  return (gamma_int (a + b + 1.) / gamma_int (a + 1.)
-         * gamma_int (c + d + 1.) / gamma_int (b + 1.)
-         * gamma_int (a + c + 1.) / gamma_int (c + 1.)
-         * gamma_int (b + d + 1.) / gamma_int (d + 1.)
-         / gamma_int (a + b + c + d + 1.));
+  return exp (log_gamma_int (a + b + 1.) -  log_gamma_int (a + 1.)
+           + log_gamma_int (c + d + 1.) - log_gamma_int (b + 1.)
+           + log_gamma_int (a + c + 1.) - log_gamma_int (c + 1.)
+           + log_gamma_int (b + d + 1.) - log_gamma_int (d + 1.)
+           - log_gamma_int (a + b + c + d + 1.));
 }
 
 /* Swap the contents of A and B. */
@@ -2130,6 +2132,7 @@ static void
 calc_fisher (int a, int b, int c, int d, double *fisher1, double *fisher2)
 {
   int pt;
+  double pn1;
 
   if (MIN (c, d) < MIN (a, b))
     swap (&a, &c), swap (&b, &d);
@@ -2143,13 +2146,21 @@ calc_fisher (int a, int b, int c, int d, double *fisher1, double *fisher2)
        swap (&a, &c), swap (&b, &d);
     }
 
-  *fisher1 = 0.;
-  for (pt = 0; pt <= a; pt++)
-    *fisher1 += Pr (a - pt, b + pt, c + pt, d - pt);
+  pn1 = Pr (a, b, c, d);
+  *fisher1 = pn1;
+  for (pt = 1; pt <= a; pt++)
+    {
+      *fisher1 += Pr (a - pt, b + pt, c + pt, d - pt);
+    }
 
   *fisher2 = *fisher1;
+
   for (pt = 1; pt <= b; pt++)
-    *fisher2 += Pr (a + pt, b - pt, c - pt, d + pt);
+    {
+      double p = Pr (a + pt, b - pt, c - pt, d + pt);
+      if (p < pn1)
+       *fisher2 += p;
+    }
 }
 
 /* Calculates chi-squares into CHISQ.  MAT is a matrix with N_COLS
@@ -2234,8 +2245,7 @@ calc_chisq (struct pivot_table *pt,
       }
 
       /* Fisher. */
-      if (f11 < 5. || f12 < 5. || f21 < 5. || f22 < 5.)
-       calc_fisher (f11 + .5, f12 + .5, f21 + .5, f22 + .5, fisher1, fisher2);
+      calc_fisher (f11 + .5, f12 + .5, f21 + .5, f22 + .5, fisher1, fisher2);
     }
 
   /* Calculate Mantel-Haenszel. */