1 /*
2 * Copyright (c) 2012, 2013, 2020
3 * Inferno Nettverk A/S, Norway. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. The above copyright notice, this list of conditions and the following
9 * disclaimer must appear in all copies of the software, derivative works
10 * or modified versions, and any portions thereof, aswell as in all
11 * supporting documentation.
12 * 2. All advertising materials mentioning features or use of this software
13 * must display the following acknowledgement:
14 * This product includes software developed by
15 * Inferno Nettverk A/S, Norway.
16 * 3. The name of the author may not be used to endorse or promote products
17 * derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * Inferno Nettverk A/S requests users of this software to return to
31 *
32 * Software Distribution Coordinator or sdc@inet.no
33 * Inferno Nettverk A/S
34 * Oslo Research Park
35 * Gaustadall�en 21
36 * NO-0349 Oslo
37 * Norway
38 *
39 * any improvements or extensions that they make and grant Inferno Nettverk A/S
40 * the rights to redistribute these changes.
41 *
42 */
43
44 #include "common.h"
45
46 static const char rcsid[] =
47 "$Id: math.c,v 1.16.10.2 2020/11/11 16:11:59 karls Exp $";
48
49 #include <math.h>
50
51 unsigned long
medtv(struct timeval * tvarr,size_t tvsize)52 medtv(struct timeval *tvarr, size_t tvsize)
53 {
54 struct timeval med;
55
56 if (tvsize == 0)
57 return 0;
58 else if (tvsize == 1)
59 med = tvarr[tvsize - 1];
60 else if (tvsize % 2 == 1)
61 med = tvarr[(tvsize - 1) / 2];
62 else {
63 timeradd(&tvarr[(tvsize - 1) / 2], &tvarr[(tvsize - 1) / 2 + 1], &med);
64 return tv2us(&med) / 2;
65 }
66
67 return tv2us(&med);
68 }
69
70 unsigned long
avgtv(struct timeval * tvarr,size_t tvsize)71 avgtv(struct timeval *tvarr, size_t tvsize)
72 {
73 struct timeval sum, nsum;
74 size_t i;
75
76 if (tvsize == 0)
77 return 0;
78
79 timerclear(&sum);
80 for (i = 0; i < tvsize; ++i) {
81 /* don't assume multiple arguments to timer*() can point to same mem. */
82 timeradd(&sum, &tvarr[i], &nsum);
83 sum = nsum;
84 }
85
86 return tv2us(&sum) / tvsize;
87 }
88
89 unsigned long
stddevtv(struct timeval * tvarr,size_t tvsize,unsigned long avg)90 stddevtv(struct timeval *tvarr, size_t tvsize, unsigned long avg)
91 {
92 unsigned long long diffsum;
93 size_t i;
94
95 if (tvsize <= 1)
96 return 0;
97
98 /* get the squared sum of differences from the mean */
99 for (i = 0, diffsum = 0; i < tvsize; ++i) {
100 const unsigned long long diff = tv2us(&tvarr[i]) - avg;
101
102 diffsum += diff * diff;
103 }
104
105 return (unsigned long)lround(sqrt(((double)diffsum) / tvsize));
106 }
107