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statistc.cpp
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1 /**********************************************************************
2 * File: statistc.c (Formerly stats.c)
3 * Description: Simple statistical package for integer values.
4 * Author: Ray Smith
5 * Created: Mon Feb 04 16:56:05 GMT 1991
6 *
7 * (C) Copyright 1991, Hewlett-Packard Ltd.
8 ** Licensed under the Apache License, Version 2.0 (the "License");
9 ** you may not use this file except in compliance with the License.
10 ** You may obtain a copy of the License at
11 ** http://www.apache.org/licenses/LICENSE-2.0
12 ** Unless required by applicable law or agreed to in writing, software
13 ** distributed under the License is distributed on an "AS IS" BASIS,
14 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 ** See the License for the specific language governing permissions and
16 ** limitations under the License.
17 *
18 **********************************************************************/
19
20 // Include automatically generated configuration file if running autoconf.
21 #ifdef HAVE_CONFIG_H
22 #include "config_auto.h"
23 #endif
24
25 #include "mfcpch.h" //precompiled headers
26 #include "statistc.h"
27 #include <string.h>
28 #include <math.h>
29 #include <stdlib.h>
30 #include "helpers.h"
31 #include "scrollview.h"
32 #include "tprintf.h"
33
34 /**********************************************************************
35 * STATS::STATS
36 *
37 * Construct a new stats element by allocating and zeroing the memory.
38 **********************************************************************/
39 STATS::STATS(inT32 min_bucket_value, inT32 max_bucket_value_plus_1) {
40 if (max_bucket_value_plus_1 <= min_bucket_value) {
41 min_bucket_value = 0;
42 max_bucket_value_plus_1 = 1;
43 }
44 rangemin_ = min_bucket_value; // setup
45 rangemax_ = max_bucket_value_plus_1;
46 buckets_ = new inT32[rangemax_ - rangemin_];
47 clear();
48 }
49
50 STATS::STATS() {
51 rangemax_ = 0;
52 rangemin_ = 0;
53 buckets_ = NULL;
54 }
55
56 /**********************************************************************
57 * STATS::set_range
58 *
59 * Alter the range on an existing stats element.
60 **********************************************************************/
61 bool STATS::set_range(inT32 min_bucket_value, inT32 max_bucket_value_plus_1) {
62 if (max_bucket_value_plus_1 <= min_bucket_value) {
63 return false;
64 }
65 if (rangemax_ - rangemin_ != max_bucket_value_plus_1 - min_bucket_value) {
66 delete [] buckets_;
67 buckets_ = new inT32[max_bucket_value_plus_1 - min_bucket_value];
68 }
69 rangemin_ = min_bucket_value; // setup
70 rangemax_ = max_bucket_value_plus_1;
71 clear(); // zero it
72 return true;
73 }
74
75 /**********************************************************************
76 * STATS::clear
77 *
78 * Clear out the STATS class by zeroing all the buckets.
79 **********************************************************************/
80 void STATS::clear() { // clear out buckets
81 total_count_ = 0;
82 if (buckets_ != NULL)
83 memset(buckets_, 0, (rangemax_ - rangemin_) * sizeof(buckets_[0]));
84 }
85
86 /**********************************************************************
87 * STATS::~STATS
88 *
89 * Destructor for a stats class.
90 **********************************************************************/
91 STATS::~STATS () {
92 if (buckets_ != NULL) {
93 delete [] buckets_;
94 buckets_ = NULL;
95 }
96 }
97
98 /**********************************************************************
99 * STATS::add
100 *
101 * Add a set of samples to (or delete from) a pile.
102 **********************************************************************/
103 void STATS::add(inT32 value, inT32 count) {
104 if (buckets_ == NULL) {
105 return;
106 }
107 value = ClipToRange(value, rangemin_, rangemax_ - 1);
108 buckets_[value - rangemin_] += count;
109 total_count_ += count; // keep count of total
110 }
111
112 /**********************************************************************
113 * STATS::mode
114 *
115 * Find the mode of a stats class.
116 **********************************************************************/
117 inT32 STATS::mode() const { // get mode of samples
118 if (buckets_ == NULL) {
119 return rangemin_;
120 }
121 inT32 max = buckets_[0]; // max cell count
122 inT32 maxindex = 0; // index of max
123 for (int index = rangemax_ - rangemin_ - 1; index > 0; --index) {
124 if (buckets_[index] > max) {
125 max = buckets_[index]; // find biggest
126 maxindex = index;
127 }
128 }
129 return maxindex + rangemin_; // index of biggest
130 }
131
132 /**********************************************************************
133 * STATS::mean
134 *
135 * Find the mean of a stats class.
136 **********************************************************************/
137 double STATS::mean() const { //get mean of samples
138 if (buckets_ == NULL || total_count_ <= 0) {
139 return static_cast<double>(rangemin_);
140 }
141 inT64 sum = 0;
142 for (int index = rangemax_ - rangemin_ - 1; index >= 0; --index) {
143 sum += static_cast< inT64 >(index) * buckets_[index];
144 }
145 return static_cast<double>(sum) / total_count_ + rangemin_;
146 }
147
148 /**********************************************************************
149 * STATS::sd
150 *
151 * Find the standard deviation of a stats class.
152 **********************************************************************/
153 double STATS::sd() const { //standard deviation
154 if (buckets_ == NULL || total_count_ <= 0) {
155 return 0.0;
156 }
157 inT64 sum = 0;
158 double sqsum = 0.0;
159 for (int index = rangemax_ - rangemin_ - 1; index >= 0; --index) {
160 sum += static_cast< inT64 >(index) * buckets_[index];
161 sqsum += static_cast<double>(index) * index * buckets_[index];
162 }
163 double variance = static_cast<double>(sum) / total_count_;
164 variance = sqsum / total_count_ - variance * variance;
165 if (variance > 0.0)
166 return sqrt(variance);
167 return 0.0;
168 }
169
170 /**********************************************************************
171 * STATS::ile
172 *
173 * Returns the fractile value such that frac fraction (in [0,1]) of samples
174 * has a value less than the return value.
175 **********************************************************************/
176 double STATS::ile(double frac) const {
177 if (buckets_ == NULL || total_count_ == 0) {
178 return static_cast<double>(rangemin_);
179 }
180 #if 0
181 // TODO(rays) The existing code doesn't seem to be doing the right thing
182 // with target a double but this substitute crashes the code that uses it.
183 // Investigate and fix properly.
184 int target = IntCastRounded(frac * total_count_);
185 target = ClipToRange(target, 1, total_count_);
186 #else
187 double target = frac * total_count_;
188 target = ClipToRange(target, 1.0, static_cast<double>(total_count_));
189 #endif
190 int sum = 0;
191 int index = 0;
192 for (index = 0; index < rangemax_ - rangemin_ && sum < target;
193 sum += buckets_[index++]);
194 if (index > 0) {
195 ASSERT_HOST(buckets_[index - 1] > 0);
196 return rangemin_ + index -
197 static_cast<double>(sum - target) / buckets_[index - 1];
198 } else {
199 return static_cast<double>(rangemin_);
200 }
201 }
202
203 /**********************************************************************
204 * STATS::min_bucket
205 *
206 * Find REAL minimum bucket - ile(0.0) isnt necessarily correct
207 **********************************************************************/
208 inT32 STATS::min_bucket() const { // Find min
209 if (buckets_ == NULL || total_count_ == 0) {
210 return rangemin_;
211 }
212 inT32 min = 0;
213 for (min = 0; (min < rangemax_ - rangemin_) && (buckets_[min] == 0); min++);
214 return rangemin_ + min;
215 }
216
217
218 /**********************************************************************
219 * STATS::max_bucket
220 *
221 * Find REAL maximum bucket - ile(1.0) isnt necessarily correct
222 **********************************************************************/
223
224 inT32 STATS::max_bucket() const { // Find max
225 if (buckets_ == NULL || total_count_ == 0) {
226 return rangemin_;
227 }
228 inT32 max;
229 for (max = rangemax_ - rangemin_ - 1; max > 0 && buckets_[max] == 0; max--);
230 return rangemin_ + max;
231 }
232
233 /**********************************************************************
234 * STATS::median
235 *
236 * Finds a more useful estimate of median than ile(0.5).
237 *
238 * Overcomes a problem with ile() - if the samples are, for example,
239 * 6,6,13,14 ile(0.5) return 7.0 - when a more useful value would be midway
240 * between 6 and 13 = 9.5
241 **********************************************************************/
242 double STATS::median() const { //get median
243 if (buckets_ == NULL) {
244 return static_cast<double>(rangemin_);
245 }
246 double median = ile(0.5);
247 int median_pile = static_cast<int>(floor(median));
248 if ((total_count_ > 1) && (pile_count(median_pile) == 0)) {
249 inT32 min_pile;
250 inT32 max_pile;
251 /* Find preceeding non zero pile */
252 for (min_pile = median_pile; pile_count(min_pile) == 0; min_pile--);
253 /* Find following non zero pile */
254 for (max_pile = median_pile; pile_count(max_pile) == 0; max_pile++);
255 median = (min_pile + max_pile) / 2.0;
256 }
257 return median;
258 }
259
260 /**********************************************************************
261 * STATS::local_min
262 *
263 * Return TRUE if this point is a local min.
264 **********************************************************************/
265 bool STATS::local_min(inT32 x) const {
266 if (buckets_ == NULL) {
267 return false;
268 }
269 x = ClipToRange(x, rangemin_, rangemax_ - 1) - rangemin_;
270 if (buckets_[x] == 0)
271 return true;
272 inT32 index; // table index
273 for (index = x - 1; index >= 0 && buckets_[index] == buckets_[x]; --index);
274 if (index >= 0 && buckets_[index] < buckets_[x])
275 return false;
276 for (index = x + 1; index < rangemax_ - rangemin_ &&
277 buckets_[index] == buckets_[x]; ++index);
278 if (index < rangemax_ - rangemin_ && buckets_[index] < buckets_[x])
279 return false;
280 else
281 return true;
282 }
283
284 /**********************************************************************
285 * STATS::smooth
286 *
287 * Apply a triangular smoothing filter to the stats.
288 * This makes the modes a bit more useful.
289 * The factor gives the height of the triangle, i.e. the weight of the
290 * centre.
291 **********************************************************************/
292 void STATS::smooth(inT32 factor) {
293 if (buckets_ == NULL || factor < 2) {
294 return;
295 }
296 STATS result(rangemin_, rangemax_);
297 int entrycount = rangemax_ - rangemin_;
298 for (int entry = 0; entry < entrycount; entry++) {
299 //centre weight
300 int count = buckets_[entry] * factor;
301 for (int offset = 1; offset < factor; offset++) {
302 if (entry - offset >= 0)
303 count += buckets_[entry - offset] * (factor - offset);
304 if (entry + offset < entrycount)
305 count += buckets_[entry + offset] * (factor - offset);
306 }
307 result.add(entry + rangemin_, count);
308 }
309 total_count_ = result.total_count_;
310 memcpy(buckets_, result.buckets_, entrycount * sizeof(buckets_[0]));
311 }
312
313 /**********************************************************************
314 * STATS::cluster
315 *
316 * Cluster the samples into max_cluster clusters.
317 * Each call runs one iteration. The array of clusters must be
318 * max_clusters+1 in size as cluster 0 is used to indicate which samples
319 * have been used.
320 * The return value is the current number of clusters.
321 **********************************************************************/
322
323 inT32 STATS::cluster(float lower, // thresholds
324 float upper,
325 float multiple, // distance threshold
326 inT32 max_clusters, // max no to make
327 STATS *clusters) { // array of clusters
328 BOOL8 new_cluster; // added one
329 float *centres; // cluster centres
330 inT32 entry; // bucket index
331 inT32 cluster; // cluster index
332 inT32 best_cluster; // one to assign to
333 inT32 new_centre = 0; // residual mode
334 inT32 new_mode; // pile count of new_centre
335 inT32 count; // pile to place
336 float dist; // from cluster
337 float min_dist; // from best_cluster
338 inT32 cluster_count; // no of clusters
339
340 if (buckets_ == NULL || max_clusters < 1)
341 return 0;
342 centres = new float[max_clusters + 1];
343 for (cluster_count = 1; cluster_count <= max_clusters
344 && clusters[cluster_count].buckets_ != NULL
345 && clusters[cluster_count].total_count_ > 0;
346 cluster_count++) {
347 centres[cluster_count] =
348 static_cast<float>(clusters[cluster_count].ile(0.5));
349 new_centre = clusters[cluster_count].mode();
350 for (entry = new_centre - 1; centres[cluster_count] - entry < lower
351 && entry >= rangemin_
352 && pile_count(entry) <= pile_count(entry + 1);
353 entry--) {
354 count = pile_count(entry) - clusters[0].pile_count(entry);
355 if (count > 0) {
356 clusters[cluster_count].add(entry, count);
357 clusters[0].add (entry, count);
358 }
359 }
360 for (entry = new_centre + 1; entry - centres[cluster_count] < lower
361 && entry < rangemax_
362 && pile_count(entry) <= pile_count(entry - 1);
363 entry++) {
364 count = pile_count(entry) - clusters[0].pile_count(entry);
365 if (count > 0) {
366 clusters[cluster_count].add(entry, count);
367 clusters[0].add(entry, count);
368 }
369 }
370 }
371 cluster_count--;
372
373 if (cluster_count == 0) {
374 clusters[0].set_range(rangemin_, rangemax_);
375 }
376 do {
377 new_cluster = FALSE;
378 new_mode = 0;
379 for (entry = 0; entry < rangemax_ - rangemin_; entry++) {
380 count = buckets_[entry] - clusters[0].buckets_[entry];
381 //remaining pile
382 if (count > 0) { //any to handle
383 min_dist = static_cast<float>(MAX_INT32);
384 best_cluster = 0;
385 for (cluster = 1; cluster <= cluster_count; cluster++) {
386 dist = entry + rangemin_ - centres[cluster];
387 //find distance
388 if (dist < 0)
389 dist = -dist;
390 if (dist < min_dist) {
391 min_dist = dist; //find least
392 best_cluster = cluster;
393 }
394 }
395 if (min_dist > upper //far enough for new
396 && (best_cluster == 0
397 || entry + rangemin_ > centres[best_cluster] * multiple
398 || entry + rangemin_ < centres[best_cluster] / multiple)) {
399 if (count > new_mode) {
400 new_mode = count;
401 new_centre = entry + rangemin_;
402 }
403 }
404 }
405 }
406 // need new and room
407 if (new_mode > 0 && cluster_count < max_clusters) {
408 cluster_count++;
409 new_cluster = TRUE;
410 if (!clusters[cluster_count].set_range(rangemin_, rangemax_))
411 return 0;
412 centres[cluster_count] = static_cast<float>(new_centre);
413 clusters[cluster_count].add(new_centre, new_mode);
414 clusters[0].add(new_centre, new_mode);
415 for (entry = new_centre - 1; centres[cluster_count] - entry < lower
416 && entry >= rangemin_
417 && pile_count (entry) <= pile_count(entry + 1); entry--) {
418 count = pile_count(entry) - clusters[0].pile_count(entry);
419 if (count > 0) {
420 clusters[cluster_count].add(entry, count);
421 clusters[0].add(entry, count);
422 }
423 }
424 for (entry = new_centre + 1; entry - centres[cluster_count] < lower
425 && entry < rangemax_
426 && pile_count (entry) <= pile_count(entry - 1); entry++) {
427 count = pile_count(entry) - clusters[0].pile_count(entry);
428 if (count > 0) {
429 clusters[cluster_count].add(entry, count);
430 clusters[0].add (entry, count);
431 }
432 }
433 centres[cluster_count] =
434 static_cast<float>(clusters[cluster_count].ile(0.5));
435 }
436 } while (new_cluster && cluster_count < max_clusters);
437 delete [] centres;
438 return cluster_count;
439 }
440
441 /**********************************************************************
442 * STATS::print
443 *
444 * Prints a summary and table of the histogram.
445 **********************************************************************/
446 void STATS::print() const {
447 if (buckets_ == NULL) {
448 return;
449 }
450 inT32 min = min_bucket() - rangemin_;
451 inT32 max = max_bucket() - rangemin_;
452
453 int num_printed = 0;
454 for (int index = min; index <= max; index++) {
455 if (buckets_[index] != 0) {
456 tprintf("%4d:%-3d ", rangemin_ + index, buckets_[index]);
457 if (++num_printed % 8 == 0)
458 tprintf ("\n");
459 }
460 }
461 tprintf ("\n");
462 print_summary();
463 }
464
465
466
467 /**********************************************************************
468 * STATS::print_summary
469 *
470 * Print a summary of the stats.
471 **********************************************************************/
472 void STATS::print_summary() const {
473 if (buckets_ == NULL) {
474 return;
475 }
476 inT32 min = min_bucket();
477 inT32 max = max_bucket();
478 tprintf("Total count=%d\n", total_count_);
479 tprintf("Min=%.2f Really=%d\n", ile(0.0), min);
480 tprintf("Lower quartile=%.2f\n", ile(0.25));
481 tprintf("Median=%.2f, ile(0.5)=%.2f\n", median(), ile(0.5));
482 tprintf("Upper quartile=%.2f\n", ile(0.75));
483 tprintf("Max=%.2f Really=%d\n", ile(1.0), max);
484 tprintf("Range=%d\n", max + 1 - min);
485 tprintf("Mean= %.2f\n", mean());
486 tprintf("SD= %.2f\n", sd());
487 }
488
489
490 /**********************************************************************
491 * STATS::plot
492 *
493 * Draw a histogram of the stats table.
494 **********************************************************************/
495
496 #ifndef GRAPHICS_DISABLED
497 void STATS::plot(ScrollView* window, // to draw in
498 float xorigin, // bottom left
499 float yorigin,
500 float xscale, // one x unit
501 float yscale, // one y unit
502 ScrollView::Color colour) const { // colour to draw in
503 if (buckets_ == NULL) {
504 return;
505 }
506 window->Pen(colour);
507
508 for (int index = 0; index < rangemax_ - rangemin_; index++) {
509 window->Rectangle( xorigin + xscale * index, yorigin,
510 xorigin + xscale * (index + 1),
511 yorigin + yscale * buckets_[index]);
512 }
513 }
514 #endif
515
516
517 /**********************************************************************
518 * STATS::plotline
519 *
520 * Draw a histogram of the stats table. (Line only)
521 **********************************************************************/
522
523 #ifndef GRAPHICS_DISABLED
524 void STATS::plotline(ScrollView* window, // to draw in
525 float xorigin, // bottom left
526 float yorigin,
527 float xscale, // one x unit
528 float yscale, // one y unit
529 ScrollView::Color colour) const { // colour to draw in
530 if (buckets_ == NULL) {
531 return;
532 }
533 window->Pen(colour);
534 window->SetCursor(xorigin, yorigin + yscale * buckets_[0]);
535 for (int index = 0; index < rangemax_ - rangemin_; index++) {
536 window->DrawTo(xorigin + xscale * index,
537 yorigin + yscale * buckets_[index]);
538 }
539 }
540 #endif
541
542
543 /**********************************************************************
544 * choose_nth_item
545 *
546 * Returns the index of what would b the nth item in the array
547 * if the members were sorted, without actually sorting.
548 **********************************************************************/
549
550 inT32 choose_nth_item(inT32 index, float *array, inT32 count) {
551 inT32 next_sample; // next one to do
552 inT32 next_lesser; // space for new
553 inT32 prev_greater; // last one saved
554 inT32 equal_count; // no of equal ones
555 float pivot; // proposed median
556 float sample; // current sample
557
558 if (count <= 1)
559 return 0;
560 if (count == 2) {
561 if (array[0] < array[1]) {
562 return index >= 1 ? 1 : 0;
563 }
564 else {
565 return index >= 1 ? 0 : 1;
566 }
567 }
568 else {
569 if (index < 0)
570 index = 0; // ensure legal
571 else if (index >= count)
572 index = count - 1;
573 equal_count = (inT32) (rand() % count);
574 pivot = array[equal_count];
575 // fill gap
576 array[equal_count] = array[0];
577 next_lesser = 0;
578 prev_greater = count;
579 equal_count = 1;
580 for (next_sample = 1; next_sample < prev_greater;) {
581 sample = array[next_sample];
582 if (sample < pivot) {
583 // shuffle
584 array[next_lesser++] = sample;
585 next_sample++;
586 }
587 else if (sample > pivot) {
588 prev_greater--;
589 // juggle
590 array[next_sample] = array[prev_greater];
591 array[prev_greater] = sample;
592 }
593 else {
594 equal_count++;
595 next_sample++;
596 }
597 }
598 for (next_sample = next_lesser; next_sample < prev_greater;)
599 array[next_sample++] = pivot;
600 if (index < next_lesser)
601 return choose_nth_item (index, array, next_lesser);
602 else if (index < prev_greater)
603 return next_lesser; // in equal bracket
604 else
605 return choose_nth_item (index - prev_greater,
606 array + prev_greater,
607 count - prev_greater) + prev_greater;
608 }
609 }
610
611 /**********************************************************************
612 * choose_nth_item
613 *
614 * Returns the index of what would be the nth item in the array
615 * if the members were sorted, without actually sorting.
616 **********************************************************************/
617 inT32 choose_nth_item(inT32 index, void *array, inT32 count, size_t size,
618 int (*compar)(const void*, const void*)) {
619 int result; // of compar
620 inT32 next_sample; // next one to do
621 inT32 next_lesser; // space for new
622 inT32 prev_greater; // last one saved
623 inT32 equal_count; // no of equal ones
624 inT32 pivot; // proposed median
625
626 if (count <= 1)
627 return 0;
628 if (count == 2) {
629 if (compar (array, (char *) array + size) < 0) {
630 return index >= 1 ? 1 : 0;
631 }
632 else {
633 return index >= 1 ? 0 : 1;
634 }
635 }
636 if (index < 0)
637 index = 0; // ensure legal
638 else if (index >= count)
639 index = count - 1;
640 pivot = (inT32) (rand () % count);
641 swap_entries (array, size, pivot, 0);
642 next_lesser = 0;
643 prev_greater = count;
644 equal_count = 1;
645 for (next_sample = 1; next_sample < prev_greater;) {
646 result =
647 compar ((char *) array + size * next_sample,
648 (char *) array + size * next_lesser);
649 if (result < 0) {
650 swap_entries (array, size, next_lesser++, next_sample++);
651 // shuffle
652 }
653 else if (result > 0) {
654 prev_greater--;
655 swap_entries(array, size, prev_greater, next_sample);
656 }
657 else {
658 equal_count++;
659 next_sample++;
660 }
661 }
662 if (index < next_lesser)
663 return choose_nth_item (index, array, next_lesser, size, compar);
664 else if (index < prev_greater)
665 return next_lesser; // in equal bracket
666 else
667 return choose_nth_item (index - prev_greater,
668 (char *) array + size * prev_greater,
669 count - prev_greater, size,
670 compar) + prev_greater;
671 }
672
673 /**********************************************************************
674 * swap_entries
675 *
676 * Swap 2 entries of arbitrary size in-place in a table.
677 **********************************************************************/
678 void swap_entries(void *array, // array of entries
679 size_t size, // size of entry
680 inT32 index1, // entries to swap
681 inT32 index2) {
682 char tmp;
683 char *ptr1; // to entries
684 char *ptr2;
685 size_t count; // of bytes
686
687 ptr1 = reinterpret_cast<char*>(array) + index1 * size;
688 ptr2 = reinterpret_cast<char*>(array) + index2 * size;
689 for (count = 0; count < size; count++) {
690 tmp = *ptr1;
691 *ptr1++ = *ptr2;
692 *ptr2++ = tmp; // tedious!
693 }
694 }