tsgMathUtils.hpp

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/*
 * Copyright (c) 2017, Miroslav Stoyanov
 *
 * This file is part of
 * Toolkit for Adaptive Stochastic Modeling And Non-Intrusive ApproximatioN: TASMANIAN
 *
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#ifndef __TASMANIAN_SPARSE_GRID_MATHUTILS_HPP
#define __TASMANIAN_SPARSE_GRID_MATHUTILS_HPP
 
namespace TasGrid{
 
namespace Maths{
inline int intlog2(int i){
    int result = 0;
    while (i >>= 1){ result++; }
    return result;
}
inline int int2log2(int i){ // this is effectively: 2^(floor(log_2(i))), when i == 0, this returns 1
    int result = 1;
    while (i >>= 1){ result <<= 1; }
    return result;
}
inline int int3log3(int i){
    int result = 1;
    while(i >= 1){ i /= 3; result *= 3; }
    return result;
}
inline int pow2(int p){ return (1 << p); }
inline int pow3(int p){
    int result = 1;
    for(int i=0; i<p; i++) result *= 3;
    return result;
}
 
inline double sign(double p){ return (p >= 0.0) ? 1.0 : -1.0; }
 
constexpr double pi = 3.14159265358979323846;
 
constexpr double num_tol = 1.E-12;
 
} // namespace Maths
 
} // namespace TasGrid
 
#endif