math: Make 'accumulate' a feature of order statistics, not all stats.

[pspp] / src / math / percentiles.c

diff --git a/src/math/percentiles.c b/src/math/percentiles.c
index c76bb492ba767a90ffa2c03c8d35bf8a7d532ab6..a9b2913b5c0a47e1f91502abfdde5435b4be7c72 100644 (file)
--- a/src/math/percentiles.c
+++ b/src/math/percentiles.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 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
@@ -15,62 +15,46 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include <config.h>
-#include "percentiles.h"
-#include <math/order-stats.h>
 
+#include "math/percentiles.h"
 
-#include "gettext.h"
-#define _(msgid) gettext (msgid)
-#define N_(msgid) msgid
-
-#include <libpspp/assertion.h>
-#include <libpspp/cast.h>
-#include <data/val-type.h>
-#include <gl/xalloc.h>
-#include <data/variable.h>
-#include <data/casereader.h>
-
-
-const char *const ptile_alg_desc[] = {
-  "",
-  N_("HAverage"),
-  N_("Weighted Average"),
-  N_("Rounded"),
-  N_("Empirical"),
-  N_("Empirical with averaging")
-};
-
+#include "data/casereader.h"
+#include "data/val-type.h"
+#include "data/variable.h"
+#include "libpspp/assertion.h"
+#include "libpspp/cast.h"
+#include "math/order-stats.h"
 
+#include "gl/xalloc.h"
 
+/* Return the value of the percentile. */
 double
 percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
 {
   struct percentile *mutable = CONST_CAST (struct percentile *, ptl);
   const struct order_stats *os = &ptl->parent;
 
-  assert (os->cc == ptl->w);
-
-  if ( ptl->g1 == SYSMIS)
+  if (ptl->g1 == SYSMIS)
     mutable->g1 = (os->k[0].tc - os->k[0].cc) / os->k[0].c_p1;
 
-  if ( ptl->g1_star == SYSMIS)
+  if (ptl->g1_star == SYSMIS)
     mutable->g1_star = os->k[0].tc - os->k[0].cc;
 
-  if ( ptl->g2 == SYSMIS)
+  if (ptl->g2 == SYSMIS)
     {
-      if ( os->k[1].c == 0 )
+      if (os->k[1].c == 0)
        mutable->g2 = os->k[1].tc / os->k[1].c_p1;
-      else if ( os->k[1].c_p1 == 0 )
+      else if (os->k[1].c_p1 == 0)
        mutable->g2 = 0;
       else
        mutable->g2 = (os->k[1].tc - os->k[1].cc) / os->k[1].c_p1;
     }
 
-  if ( ptl->g2_star == SYSMIS)
+  if (ptl->g2_star == SYSMIS)
     {
-      if ( os->k[1].c == 0 )
+      if (os->k[1].c == 0)
        mutable->g2_star = os->k[1].tc;
-      else if ( os->k[1].c_p1 == 0 )
+      else if (os->k[1].c_p1 == 0)
        mutable->g2_star = 0;
       else
        mutable->g2_star = os->k[1].tc - os->k[1].cc;
@@ -79,11 +63,11 @@ percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
   switch (alg)
     {
     case PC_WAVERAGE:
-      if ( ptl->g1_star >= 1.0)
+      if (ptl->g1_star >= 1.0)
        return os->k[0].y_p1;
       else
        {
-         double a = ( os->k[0].y == SYSMIS ) ? 0 : os->k[0].y;
+         double a = (os->k[0].y == SYSMIS) ? 0 : os->k[0].y;
 
          if (os->k[0].c_p1 >= 1.0)
            return (1 - ptl->g1_star) * a + ptl->g1_star * os->k[0].y_p1;
@@ -94,7 +78,7 @@ percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
 
     case PC_ROUND:
       {
-       double a = ( os->k[0].y == SYSMIS ) ? 0 : os->k[0].y;
+       double a = (os->k[0].y == SYSMIS) ? 0 : os->k[0].y;
 
        if (os->k[0].c_p1 >= 1.0)
          return (ptl->g1_star < 0.5) ? a : os->k[0].y_p1;
@@ -104,24 +88,24 @@ percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
       break;
 
     case PC_EMPIRICAL:
-      if ( ptl->g1_star == 0 )
+      if (ptl->g1_star == 0)
        return os->k[0].y;
       else
        return os->k[0].y_p1;
       break;
 
     case PC_HAVERAGE:
-      if ( ptl->g2_star >= 1.0)
+      if (ptl->g2_star >= 1.0)
        {
          return os->k[1].y_p1;
        }
       else
        {
-         double a = ( os->k[1].y == SYSMIS ) ? 0 : os->k[1].y;
+         double a = (os->k[1].y == SYSMIS) ? 0 : os->k[1].y;
 
-         if ( os->k[1].c_p1 >= 1.0)
+         if (os->k[1].c_p1 >= 1.0)
            {
-             if ( ptl->g2_star == 0)
+             if (ptl->g2_star == 0)
                return os->k[1].y;
 
              return (1 - ptl->g2_star) * a + ptl->g2_star * os->k[1].y_p1;
@@ -135,7 +119,7 @@ percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
       break;
 
     case PC_AEMPIRICAL:
-      if ( ptl->g1_star == 0 )
+      if (ptl->g1_star == 0)
        return (os->k[0].y + os->k[0].y_p1)/ 2.0;
       else
        return os->k[0].y_p1;
@@ -156,38 +140,35 @@ static void
 destroy (struct statistic *stat)
 {
   struct percentile *ptl = UP_CAST (stat, struct percentile, parent.parent);
-  struct order_stats *os = &ptl->parent;
-  free (os->k);
   free (ptl);
 }
 
-
+/* Create the Pth percentile.
+   W is the total sum of weights in the data set.
+*/
 struct percentile *
 percentile_create (double p, double W)
 {
-  struct percentile *ptl = xzalloc (sizeof (*ptl));
-  struct order_stats *os = &ptl->parent;
-  struct statistic *stat = &os->parent;
-
   assert (p >= 0);
   assert (p <= 1.0);
 
-  ptl->ptile = p;
-  ptl->w = W;
-
-  os->n_k = 2;
-  os->k = xcalloc (sizeof (*os->k), 2);
-  os->k[0].tc = W * p;
-  os->k[1].tc = (W + 1.0) * p;
-
-  ptl->g1 = ptl->g1_star = SYSMIS;
-  ptl->g2 = ptl->g2_star = SYSMIS;
-
-  os->k[1].y_p1 = os->k[1].y = SYSMIS;
-  os->k[0].y_p1 = os->k[0].y = SYSMIS;
-
-  stat->destroy = destroy;
-
+  struct percentile *ptl = xmalloc (sizeof *ptl);
+  *ptl = (struct percentile) {
+    .parent = {
+      .parent = {
+        .destroy = destroy
+      },
+      .k = ptl->k,
+      .n_k = 2,
+    },
+    .ptile = p,
+    .w = W,
+    .g1 = SYSMIS,
+    .g1_star = SYSMIS,
+    .g2 = SYSMIS,
+    .g2_star = SYSMIS,
+    .k[0] = { .tc = W * p, .y = SYSMIS, .y_p1 = SYSMIS },
+    .k[1] = { .tc = (W + 1.0) * p, .y = SYSMIS, .y_p1 = SYSMIS },
+  };
   return ptl;
 }
-