Changeset View
Changeset View
Standalone View
Standalone View
libs/image/vc_extra_math.h
- This file was added.
1 | /* | ||||
---|---|---|---|---|---|
2 | * Copyright (c) 2018 Iván Santa María <ghevan@gmail.com> | ||||
3 | * | ||||
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 2 of the License, or | ||||
7 | * (at your option) any later version. | ||||
8 | * | ||||
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. | ||||
13 | * | ||||
14 | * You should have received a copy of the GNU General Public License | ||||
15 | * along with this program; if not, write to the Free Software | ||||
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | ||||
17 | */ | ||||
18 | | ||||
19 | #ifndef VC_ADDITIONAL_MATH_H | ||||
20 | #define VC_ADDITIONAL_MATH_H | ||||
21 | | ||||
22 | #include <config-vc.h> | ||||
23 | | ||||
24 | #if defined HAVE_VC | ||||
25 | | ||||
26 | #include <Vc/Vc> | ||||
27 | #include <Vc/IO> | ||||
28 | | ||||
29 | class VcExtraMath | ||||
30 | { | ||||
31 | public: | ||||
32 | // vectorized erf function, precision 1e-5 | ||||
33 | static inline Vc::float_v erf(Vc::float_v x) { | ||||
34 | Vc::float_v xa = abs(x); | ||||
35 | Vc::float_m precisionLimit(xa >= 9.3f); // wrong result for any number beyond this | ||||
36 | xa(precisionLimit) = 0; | ||||
37 | Vc::float_v sign(Vc::One); | ||||
38 | Vc::float_m invertMask = x < 0.f; | ||||
39 | sign(invertMask) = -1.f; | ||||
40 | | ||||
41 | // CONSTANTS | ||||
42 | float a1 = 0.254829592; | ||||
43 | float a2 = -0.284496736; | ||||
44 | float a3 = 1.421413741; | ||||
45 | float a4 = -1.453152027; | ||||
46 | float a5 = 1.061405429; | ||||
47 | float p = 0.3275911; | ||||
48 | | ||||
49 | Vc::float_v t = 1.0f / (1.0f + p * xa); | ||||
50 | Vc::float_v y = 1.0f - (((((a5 * t + a4) * t) + a3) * t + a2) * t + a1) * t * exp(-xa * xa); | ||||
51 | y(precisionLimit) = 1.0f; | ||||
52 | return sign * y; | ||||
53 | } | ||||
54 | }; | ||||
55 | #endif /* defined HAVE_VC */ | ||||
56 | | ||||
57 | | ||||
58 | #endif // VC_ADDITIONAL_MATH_H |