NumCpp  2.12.1
A Templatized Header Only C++ Implementation of the Python NumPy Library
Random/gamma.hpp
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1
28#pragma once
29
30#include <algorithm>
31#include <random>
32#include <string>
33
36#include "NumCpp/Core/Shape.hpp"
37#include "NumCpp/NdArray.hpp"
39
40namespace nc::random
41{
42 namespace detail
43 {
44 //============================================================================
45 // Method Description:
56 template<typename dtype, typename GeneratorType = std::mt19937>
57 dtype gamma(GeneratorType& generator, dtype inGammaShape, dtype inScaleValue = 1)
58 {
60
61 if (inGammaShape <= 0)
62 {
63 THROW_INVALID_ARGUMENT_ERROR("input gamma shape should be greater than zero.");
64 }
65
66 if (inScaleValue <= 0)
67 {
68 THROW_INVALID_ARGUMENT_ERROR("input scale should be greater than zero.");
69 }
70
71 std::gamma_distribution<dtype> dist(inGammaShape, inScaleValue);
72 return dist(generator);
73 }
74
75 //============================================================================
76 // Method Description:
89 template<typename dtype, typename GeneratorType = std::mt19937>
90 NdArray<dtype> gamma(GeneratorType& generator, const Shape& inShape, dtype inGammaShape, dtype inScaleValue = 1)
91 {
93
94 if (inGammaShape <= 0)
95 {
96 THROW_INVALID_ARGUMENT_ERROR("input gamma shape should be greater than zero.");
97 }
98
99 if (inScaleValue <= 0)
100 {
101 THROW_INVALID_ARGUMENT_ERROR("input scale should be greater than zero.");
102 }
103
104 NdArray<dtype> returnArray(inShape);
105
106 std::gamma_distribution<dtype> dist(inGammaShape, inScaleValue);
107
108 std::for_each(returnArray.begin(),
109 returnArray.end(),
110 [&generator, &dist](dtype& value) -> void { value = dist(generator); });
111
112 return returnArray;
113 }
114 } // namespace detail
115
116 //============================================================================
117 // Method Description:
127 template<typename dtype>
128 dtype gamma(dtype inGammaShape, dtype inScaleValue = 1)
129 {
130 return detail::gamma(generator_, inGammaShape, inScaleValue);
131 }
132
133 //============================================================================
134 // Method Description:
146 template<typename dtype>
147 NdArray<dtype> gamma(const Shape& inShape, dtype inGammaShape, dtype inScaleValue = 1)
148 {
149 return detail::gamma(generator_, inShape, inGammaShape, inScaleValue);
150 }
151} // namespace nc::random
#define THROW_INVALID_ARGUMENT_ERROR(msg)
Definition: Error.hpp:37
#define STATIC_ASSERT_ARITHMETIC(dtype)
Definition: StaticAsserts.hpp:39
Holds 1D and 2D arrays, the main work horse of the NumCpp library.
Definition: NdArrayCore.hpp:139
iterator end() noexcept
Definition: NdArrayCore.hpp:1623
iterator begin() noexcept
Definition: NdArrayCore.hpp:1315
A Shape Class for NdArrays.
Definition: Core/Shape.hpp:41
dtype gamma(GeneratorType &generator, dtype inGammaShape, dtype inScaleValue=1)
Definition: Random/gamma.hpp:57
Definition: Random/bernoulli.hpp:41
dtype gamma(dtype inGammaShape, dtype inScaleValue=1)
Definition: Random/gamma.hpp:128
static std::mt19937_64 generator_
generator function
Definition: generator.hpp:35
void for_each(InputIt first, InputIt last, UnaryFunction f)
Definition: StlAlgorithms.hpp:225