Replace more uses of 'cnt' by 'n'.

[pspp] / src / math / moments.c

diff --git a/src/math/moments.c b/src/math/moments.c
index 2934dd7ad5a547807b7395af925def288f83cb28..517219d54fcf5d3cc159b4b64c8f6454f64a5bd4 100644 (file)
--- a/src/math/moments.c
+++ b/src/math/moments.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 1997-9, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2010, 2011 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
@@ -15,16 +15,19 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include <config.h>
-#include "moments.h"
+
+#include "math/moments.h"
+
 #include <assert.h>
 #include <math.h>
 #include <stdlib.h>
-#include <libpspp/alloc.h>
-#include <libpspp/misc.h>
-#include <data/value.h>
 
-#include "gettext.h"
-#define _(msgid) gettext (msgid)
+#include "data/val-type.h"
+#include "data/value.h"
+#include "libpspp/misc.h"
+
+#include "gl/xalloc.h"
+
 \f
 /* Calculates variance, skewness, and kurtosis into *VARIANCE,
    *SKEWNESS, and *KURTOSIS if they are non-null and not greater
@@ -47,13 +50,13 @@ calc_moments (enum moment max_moment,
 
       /* From _SPSS Statistical Algorithms, 2nd ed.,
          0-918469-89-9, section "DESCRIPTIVES". */
-      if (fabs (*variance) >= 1e-20)
+      if (fabs (s2) >= 1e-20)
         {
           if (max_moment >= MOMENT_SKEWNESS && skewness != NULL && w > 2.)
             {
               double s3 = s2 * sqrt (s2);
               double g1 = (w * d3) / ((w - 1.0) * (w - 2.0) * s3);
-              if (finite (g1))
+              if (isfinite (g1))
                 *skewness = g1;
             }
           if (max_moment >= MOMENT_KURTOSIS && kurtosis != NULL && w > 3.)
@@ -61,7 +64,7 @@ calc_moments (enum moment max_moment,
               double den = (w - 2.) * (w - 3.) * pow2 (s2);
               double g2 = (w * (w + 1) * d4 / (w - 1.) / den
                            - 3. * pow2 (d2) / den);
-              if (finite (g2))
+              if (isfinite (g2))
                 *kurtosis = g2;
             }
         }
@@ -220,12 +223,8 @@ moments_calculate (const struct moments *m,
     }
   else
     {
-      /* After the second pass we can calculate any stat.  We
-         don't support "online" computation during the second
-         pass, so As a simple self-check, the total weight for
-         the passes must agree. */
+      /* After the second pass we can calculate any stat.  */
       assert (m->pass == 2);
-      assert (m->w1 == m->w2);
 
       if (m->w2 > 0.)
         {
@@ -245,14 +244,14 @@ moments_destroy (struct moments *m)
   free (m);
 }
 
-/* Calculates the requested moments on the CNT values in ARRAY.
+/* Calculates the requested moments on the N values in ARRAY.
    Each value is given a weight of 1.  The total weight is stored
    into *WEIGHT (trivially) and the mean, variance, skewness, and
    kurtosis are stored into *MEAN, *VARIANCE, *SKEWNESS, and
    *KURTOSIS, respectively.  Any of the result pointers may be
    null, in which case no value is stored. */
 void
-moments_of_doubles (const double *array, size_t cnt,
+moments_of_doubles (const double *array, size_t n,
                     double *weight,
                     double *mean, double *variance,
                     double *skewness, double *kurtosis)
@@ -271,21 +270,21 @@ moments_of_doubles (const double *array, size_t cnt,
     max_moment = MOMENT_MEAN;
 
   init_moments (&m, max_moment);
-  for (idx = 0; idx < cnt; idx++)
+  for (idx = 0; idx < n; idx++)
     moments_pass_one (&m, array[idx], 1.);
-  for (idx = 0; idx < cnt; idx++)
+  for (idx = 0; idx < n; idx++)
     moments_pass_two (&m, array[idx], 1.);
   moments_calculate (&m, weight, mean, variance, skewness, kurtosis);
 }
 
-/* Calculates the requested moments on the CNT numeric values in
+/* Calculates the requested moments on the N numeric values in
    ARRAY.  Each value is given a weight of 1.  The total weight
    is stored into *WEIGHT (trivially) and the mean, variance,
    skewness, and kurtosis are stored into *MEAN, *VARIANCE,
    *SKEWNESS, and *KURTOSIS, respectively.  Any of the result
    pointers may be null, in which case no value is stored. */
 void
-moments_of_values (const union value *array, size_t cnt,
+moments_of_values (const union value *array, size_t n,
                    double *weight,
                    double *mean, double *variance,
                    double *skewness, double *kurtosis)
@@ -304,9 +303,9 @@ moments_of_values (const union value *array, size_t cnt,
     max_moment = MOMENT_MEAN;
 
   init_moments (&m, max_moment);
-  for (idx = 0; idx < cnt; idx++)
+  for (idx = 0; idx < n; idx++)
     moments_pass_one (&m, array[idx].f, 1.);
-  for (idx = 0; idx < cnt; idx++)
+  for (idx = 0; idx < n; idx++)
     moments_pass_two (&m, array[idx].f, 1.);
   moments_calculate (&m, weight, mean, variance, skewness, kurtosis);
 }
@@ -456,6 +455,13 @@ moments1_destroy (struct moments1 *m)
   free (m);
 }
 \f
+
+double
+calc_semean (double variance, double W)
+{
+  return sqrt (variance / W);
+}
+
 /* Returns the standard error of the skewness for the given total
    weight W.