1 /*
2 dsp/util.h
3
4 Copyright 2002-12 Tim Goetze <tim@quitte.de>
5
6 http://quitte.de/dsp/
7
8 Common math utility functions.
9
10 */
11 /*
12 This program is free software; you can redistribute it and/or
13 modify it under the terms of the GNU General Public License
14 as published by the Free Software Foundation; either version 3
15 of the License, or (at your option) any later version.
16
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
21
22 You should have received a copy of the GNU General Public License
23 along with this program; if not, write to the Free Software
24 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 02111-1307, USA or point your web browser to http://www.gnu.org.
26 */
27
28 #ifndef DSP_UTIL_H
29 #define DSP_UTIL_H
30
31 namespace DSP {
32
pow2(float x)33 inline float pow2 (float x) { return x * x; }
pow3(float x)34 inline float pow3 (float x) { return x * pow2(x); }
pow4(float x)35 inline float pow4 (float x) { return pow2 (pow2(x)); }
pow5(float x)36 inline float pow5 (float x) { return x * pow4(x); }
pow6(float x)37 inline float pow6 (float x) { return pow3 (pow2(x)); }
pow7(float x)38 inline float pow7 (float x) { return x * (pow6 (x)); }
pow8(float x)39 inline float pow8 (float x) { return pow2 (pow4 (x)); }
40
41 inline float
sgn(float x)42 sgn (float x)
43 {
44 union { float f; uint32 i; } u;
45 u.f = x;
46 u.i &= 0x80000000;
47 u.i |= 0x3F800000;
48 return u.f;
49 }
50
51 inline bool
isprime(int v)52 isprime (int v)
53 {
54 if (v <= 3)
55 return true;
56
57 if (!(v & 1))
58 return false;
59
60 for (int i = 3; i < (int) sqrt (v) + 1; i += 2)
61 if ((v % i) == 0)
62 return false;
63
64 return true;
65 }
66
67 } /* namespace DSP */
68
69 #endif /* DSP_UTIL_H */
70