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author | Sree Harsha Totakura <totakura@in.tum.de> | 2012-11-13 13:27:24 +0000 |
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committer | Sree Harsha Totakura <totakura@in.tum.de> | 2012-11-13 13:27:24 +0000 |
commit | 2b062d251328178bb63cbbb8109a821cbf308a91 (patch) | |
tree | c153c5aeff56f4c7be5dae5542d854d5cc9224ec | |
parent | 06e76ff4f8c8a673b92f1726ef1181b73067b383 (diff) | |
download | gnunet-2b062d251328178bb63cbbb8109a821cbf308a91.tar.gz gnunet-2b062d251328178bb63cbbb8109a821cbf308a91.zip |
- SD calc
-rw-r--r-- | src/testbed/standard_deviation.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/src/testbed/standard_deviation.c b/src/testbed/standard_deviation.c new file mode 100644 index 000000000..362b50b26 --- /dev/null +++ b/src/testbed/standard_deviation.c | |||
@@ -0,0 +1,123 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet | ||
3 | (C) 2008--2012 Christian Grothoff (and other contributing authors) | ||
4 | |||
5 | GNUnet is free software; you can redistribute it and/or modify | ||
6 | it under the terms of the GNU General Public License as published | ||
7 | by the Free Software Foundation; either version 3, or (at your | ||
8 | option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU General Public License | ||
16 | along with GNUnet; see the file COPYING. If not, write to the | ||
17 | Free Software Foundation, Inc., 59 Temple Place - Suite 330, | ||
18 | Boston, MA 02111-1307, USA. | ||
19 | */ | ||
20 | |||
21 | #include <gnunet/platform.h> | ||
22 | #include <gnunet/gnunet_common.h> | ||
23 | |||
24 | struct SDHandle | ||
25 | { | ||
26 | /** | ||
27 | * Squared sum of data values | ||
28 | */ | ||
29 | unsigned long long sqsum; | ||
30 | |||
31 | /** | ||
32 | * Sum of the data values | ||
33 | */ | ||
34 | unsigned long sum; | ||
35 | |||
36 | /** | ||
37 | * The average of data amounts | ||
38 | */ | ||
39 | unsigned int avg; | ||
40 | |||
41 | /** | ||
42 | * The variance | ||
43 | */ | ||
44 | unsigned int vr; | ||
45 | |||
46 | /** | ||
47 | * Number of data values | ||
48 | */ | ||
49 | unsigned int cnt; | ||
50 | }; | ||
51 | |||
52 | |||
53 | struct SDHandle * | ||
54 | GNUNET_TESTBED_SD_init () | ||
55 | { | ||
56 | return GNUNET_malloc (sizeof (struct SDHandle)); | ||
57 | } | ||
58 | |||
59 | void | ||
60 | GNUNET_TESTBED_SD_destroy (struct SDHandle *h) | ||
61 | { | ||
62 | GNUNET_free (h); | ||
63 | } | ||
64 | |||
65 | void | ||
66 | GNUNET_TESTBED_SD_add_data (struct SDHandle *h, unsigned int amount) | ||
67 | { | ||
68 | unsigned long sqavg; | ||
69 | |||
70 | h->sum += amount; | ||
71 | h->cnt++; | ||
72 | h->sqsum += ((unsigned long) amount) * ((unsigned long) amount); | ||
73 | h->avg = h->sum / h->cnt; | ||
74 | sqavg = h->avg * h->avg; | ||
75 | h->vr = (h->sqsum / h->cnt) - sqavg; | ||
76 | } | ||
77 | |||
78 | |||
79 | /** | ||
80 | * Returns the factor by which the given amount differs from the standard deviation | ||
81 | * | ||
82 | * @param h the SDhandle | ||
83 | * @param amount the value for which the deviation is returned | ||
84 | * @return the deviation from the average; GNUNET_SYSERR if the deviation cannot | ||
85 | * be calculated | ||
86 | */ | ||
87 | int | ||
88 | GNUNET_TESTBED_SD_deviation_factor (struct SDHandle *h, unsigned int amount) | ||
89 | { | ||
90 | unsigned long diff; | ||
91 | unsigned int n; | ||
92 | |||
93 | if (h->cnt < 2) | ||
94 | return GNUNET_SYSERR; | ||
95 | if (amount > h->avg) | ||
96 | diff = amount - h->avg; | ||
97 | else | ||
98 | diff = h->avg - amount; | ||
99 | diff *= diff; | ||
100 | for (n = 1; n < 4; n++) | ||
101 | if (diff < (n * n * h->vr)) | ||
102 | break; | ||
103 | return n; | ||
104 | } | ||
105 | |||
106 | |||
107 | int | ||
108 | main () | ||
109 | { | ||
110 | struct SDHandle * h = GNUNET_TESTBED_SD_init (); | ||
111 | |||
112 | GNUNET_TESTBED_SD_add_data (h, 40); | ||
113 | GNUNET_TESTBED_SD_add_data (h, 30); | ||
114 | GNUNET_TESTBED_SD_add_data (h, 40); | ||
115 | GNUNET_TESTBED_SD_add_data (h, 10); | ||
116 | GNUNET_TESTBED_SD_add_data (h, 30); | ||
117 | printf ("Average: %d\n", h->avg); | ||
118 | printf ("Variance: %d\n", h->vr); | ||
119 | printf ("Standard Deviation: %d\n", (int) sqrt (h->vr)); | ||
120 | printf ("Deviation factor: %d\n", GNUNET_TESTBED_SD_deviation (h, 40)); | ||
121 | GNUNET_TESTBED_SD_destroy (h); | ||
122 | return 0; | ||
123 | } | ||