/* PSPP - a program for statistical analysis.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2008, 2009 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
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifndef PERCENTILES_H
-#define PERCENTILES_H
+#ifndef __PERCENTILES_H__
+#define __PERCENTILES_H__
+#include <stddef.h>
-#include <libpspp/hash.h>
+#include "order-stats.h"
-struct weighted_value ;
+/* To calculate a percentile:
+
+ - Create a "struct percentile" with percentile_create().
+ - Feed in the data with order_stats_accumulate() or
+ order_stats_accumulate_idx(). The data must be in sorted order: if
+ necessary, use one of the sorting functions from sort.h to sort them.
+ - Obtain the percentile with percentile_calculate().
+ - Destroy the data structure with statistic_destroy().
+*/
/* The algorithm used to calculate percentiles */
enum pc_alg {
PC_AEMPIRICAL
} ;
+struct percentile
+{
+ struct order_stats parent;
+ double ptile;
+ double w;
-extern const char *const ptile_alg_desc[];
-
-
+ /* Mutable */
+ double g1;
+ double g1_star;
+ double g2;
+ double g2_star;
-struct percentile {
-
- /* The break point of the percentile */
- double p;
-
- /* The value of the percentile */
- double v;
+ struct k k[2];
};
+struct percentile *percentile_create (double p, double W);
+double percentile_calculate (const struct percentile *, enum pc_alg);
-/* Calculate the percentiles of the break points in pc_bp,
- placing the values in pc_val.
- wv is a sorted array of weighted values of the data set.
-*/
-void ptiles(struct hsh_table *pc_hash,
- const struct weighted_value **wv,
- int n_data,
- double w,
- enum pc_alg algorithm);
-
-
-/* Calculate Tukey's Hinges and the Whiskers for the box plot*/
-void tukey_hinges(const struct weighted_value **wv,
- int n_data,
- double w,
- double hinges[3]);
-
-
-
-/* Hash utility functions */
-int ptile_compare(const struct percentile *p1,
- const struct percentile *p2,
- void *aux);
-
-unsigned ptile_hash(const struct percentile *p, void *aux);
-
-
-#endif
+#endif /* percentiles.h */