BornAgain  1.18.0
Simulate and fit neutron and x-ray scattering at grazing incidence
MathConstants.h
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1 // ************************************************************************** //
2 //
3 // BornAgain: simulate and fit scattering at grazing incidence
4 //
5 //! @file Base/Const/MathConstants.h
6 //! @brief Defines M_PI and some more mathematical constants.
7 //!
8 //! @homepage http://www.bornagainproject.org
9 //! @license GNU General Public License v3 or higher (see COPYING)
10 //! @copyright Forschungszentrum Jülich GmbH 2018
11 //! @authors Scientific Computing Group at MLZ (see CITATION, AUTHORS)
12 //
13 // ************************************************************************** //
14 
15 #ifndef BORNAGAIN_BASE_CONST_MATHCONSTANTS_H
16 #define BORNAGAIN_BASE_CONST_MATHCONSTANTS_H
17 
18 // undefine macros that may or may not be defined, depending on compiler settings
19 #undef M_E
20 #undef M_LOG2E
21 #undef M_LOG10E
22 #undef M_LN2
23 #undef M_LN10
24 #undef M_PI
25 #undef M_PI_2
26 #undef M_PI_4
27 #undef M_1_PI
28 #undef M_2_PI
29 #undef M_2_SQRTPI
30 #undef M_SQRT2
31 #undef M_SQRT1_2
32 
33 // and define them using these potentially inactivated lines from math.h
34 #define M_E 2.7182818284590452354 /* e */
35 #define M_LOG2E 1.4426950408889634074 /* log_2 e */
36 #define M_LOG10E 0.43429448190325182765 /* log_10 e */
37 #define M_LN2 0.69314718055994530942 /* log_e 2 */
38 #define M_LN10 2.30258509299404568402 /* log_e 10 */
39 #define M_PI 3.14159265358979323846 /* pi */
40 #define M_PI_2 1.57079632679489661923 /* pi/2 */
41 #define M_PI_4 0.78539816339744830962 /* pi/4 */
42 #define M_1_PI 0.31830988618379067154 /* 1/pi */
43 #define M_2_PI 0.63661977236758134308 /* 2/pi */
44 #define M_2_SQRTPI 1.12837916709551257390 /* 2/sqrt(pi) */
45 #define M_SQRT2 1.41421356237309504880 /* sqrt(2) */
46 #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
47 
48 // additionally, we find convenient:
49 #define M_TWOPI 6.28318530717958647693
50 
51 #endif // BORNAGAIN_BASE_CONST_MATHCONSTANTS_H