| 1 | /*
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| 2 | * fast_functions.hpp
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| 3 | *
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| 4 | * Created on: Apr 1, 2010
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| 5 | * Author: crueger
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| 6 | */
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| 7 |
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| 8 | #ifndef FAST_FUNCTIONS_HPP_
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| 9 | #define FAST_FUNCTIONS_HPP_
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| 10 |
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| 11 | /**
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| 12 | * !@file
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| 13 | * This file contains several functions that need to be very fast and which are inlined for this
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| 14 | * reason.
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| 15 | *
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| 16 | * Warning: do not forget inline keyword for functions in this file to avoid multiple definitions!
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| 17 | */
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| 18 |
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| 19 | /********************************* Functions ************************************************/
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| 20 |
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| 21 | /** hard-coded determinant of a 3x3 matrix.
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| 22 | * \param a[9] matrix
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| 23 | * \return \f$det(a)\f$
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| 24 | */
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| 25 | inline double RDET3(const double a[NDIM*NDIM])
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| 26 | {
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| 27 | return ((a)[0]*(a)[4]*(a)[8] + (a)[3]*(a)[7]*(a)[2] + (a)[6]*(a)[1]*(a)[5] - (a)[2]*(a)[4]*(a)[6] - (a)[5]*(a)[7]*(a)[0] - (a)[8]*(a)[1]*(a)[3]);
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| 28 | };
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| 29 |
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| 30 | /** hard-coded determinant of a 2x2 matrix.
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| 31 | * \param a[4] matrix
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| 32 | * \return \f$det(a)\f$
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| 33 | */
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| 34 | inline double RDET2(const double a[4])
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| 35 | {
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| 36 | return ((a[0])*(a[3])-(a[1])*(a[2]));
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| 37 | };
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| 38 |
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| 39 | /** hard-coded determinant of a 2x2 matrix.
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| 40 | * \param a0 (0,0) entry of matrix
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| 41 | * \param a1 (0,1) entry of matrix
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| 42 | * \param a2 (1,0) entry of matrix
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| 43 | * \param a3 (1,1) entry of matrix
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| 44 | * \return \f$det(a)\f$
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| 45 | */
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| 46 | inline double RDET2(const double a0, const double a1, const double a2, const double a3)
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| 47 | {
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| 48 | return ((a0)*(a3)-(a1)*(a2));
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| 49 | };
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| 50 |
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| 51 | /** Returns the power of \a n with respect to \a base.
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| 52 | * \param base basis
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| 53 | * \param n power
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| 54 | * \return \f$base^n\f$
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| 55 | */
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| 56 | inline int pot(int base, int n)
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| 57 | {
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| 58 | int res = 1;
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| 59 | int j;
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| 60 | for (j=n;j--;)
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| 61 | res *= base;
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| 62 | return res;
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| 63 | };
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| 64 |
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| 65 | /*************************** Templatized functions ************************************/
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| 66 |
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| 67 | /** Flips two values.
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| 68 | * \param x first value
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| 69 | * \param y second value
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| 70 | */
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| 71 | template <typename T>
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| 72 | inline void flip(T &x, T &y)
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| 73 | {
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| 74 | T tmp;
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| 75 | tmp = x;
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| 76 | x = y;
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| 77 | y = tmp;
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| 78 | };
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| 79 |
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| 80 | #endif /* FAST_FUNCTIONS_HPP_ */
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