1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 #include "math/percentiles.h"
21 #include "data/casereader.h"
22 #include "data/val-type.h"
23 #include "data/variable.h"
24 #include "libpspp/assertion.h"
25 #include "libpspp/cast.h"
26 #include "math/order-stats.h"
28 #include "gl/xalloc.h"
31 percentile_calculate (const struct percentile *ptl, enum pc_alg alg)
33 struct percentile *mutable = CONST_CAST (struct percentile *, ptl);
34 const struct order_stats *os = &ptl->parent;
36 if (ptl->g1 == SYSMIS)
37 mutable->g1 = (os->k[0].tc - os->k[0].cc) / os->k[0].c_p1;
39 if (ptl->g1_star == SYSMIS)
40 mutable->g1_star = os->k[0].tc - os->k[0].cc;
42 if (ptl->g2 == SYSMIS)
45 mutable->g2 = os->k[1].tc / os->k[1].c_p1;
46 else if (os->k[1].c_p1 == 0)
49 mutable->g2 = (os->k[1].tc - os->k[1].cc) / os->k[1].c_p1;
52 if (ptl->g2_star == SYSMIS)
55 mutable->g2_star = os->k[1].tc;
56 else if (os->k[1].c_p1 == 0)
59 mutable->g2_star = os->k[1].tc - os->k[1].cc;
65 if (ptl->g1_star >= 1.0)
69 double a = (os->k[0].y == SYSMIS) ? 0 : os->k[0].y;
71 if (os->k[0].c_p1 >= 1.0)
72 return (1 - ptl->g1_star) * a + ptl->g1_star * os->k[0].y_p1;
74 return (1 - ptl->g1) * a + ptl->g1 * os->k[0].y_p1;
80 double a = (os->k[0].y == SYSMIS) ? 0 : os->k[0].y;
82 if (os->k[0].c_p1 >= 1.0)
83 return (ptl->g1_star < 0.5) ? a : os->k[0].y_p1;
85 return (ptl->g1 < 0.5) ? a : os->k[0].y_p1;
90 if (ptl->g1_star == 0)
97 if (ptl->g2_star >= 1.0)
103 double a = (os->k[1].y == SYSMIS) ? 0 : os->k[1].y;
105 if (os->k[1].c_p1 >= 1.0)
107 if (ptl->g2_star == 0)
110 return (1 - ptl->g2_star) * a + ptl->g2_star * os->k[1].y_p1;
114 return (1 - ptl->g2) * a + ptl->g2 * os->k[1].y_p1;
121 if (ptl->g1_star == 0)
122 return (os->k[0].y + os->k[0].y_p1)/ 2.0;
124 return os->k[0].y_p1;
139 destroy (struct statistic *stat)
141 struct percentile *ptl = UP_CAST (stat, struct percentile, parent.parent);
142 struct order_stats *os = &ptl->parent;
149 percentile_create (double p, double W)
151 struct percentile *ptl = XZALLOC (struct percentile);
152 struct order_stats *os = &ptl->parent;
153 struct statistic *stat = &os->parent;
162 os->k = xcalloc (2, sizeof (*os->k));
164 os->k[1].tc = (W + 1.0) * p;
166 ptl->g1 = ptl->g1_star = SYSMIS;
167 ptl->g2 = ptl->g2_star = SYSMIS;
169 os->k[1].y_p1 = os->k[1].y = SYSMIS;
170 os->k[0].y_p1 = os->k[0].y = SYSMIS;
172 stat->destroy = destroy;