NumCpp  2.12.1
A Templatized Header Only C++ Implementation of the Python NumPy Library
matrix_power.hpp
Go to the documentation of this file.
1
28#pragma once
29
30#include <string>
31
34#include "NumCpp/Core/Shape.hpp"
35#include "NumCpp/Core/Types.hpp"
38#include "NumCpp/NdArray.hpp"
39
40namespace nc::linalg
41{
42 //============================================================================
43 // Method Description:
59 template<typename dtype>
61 {
63
64 const Shape inShape = inArray.shape();
65 if (inShape.rows != inShape.cols)
66 {
67 THROW_INVALID_ARGUMENT_ERROR("input matrix must be square.");
68 }
69
70 if (inPower == 0)
71 {
72 return identity<double>(inShape.rows);
73 }
74
75 if (inPower == 1)
76 {
77 return inArray.template astype<double>();
78 }
79
80 if (inPower == -1)
81 {
82 return inv(inArray);
83 }
84
85 if (inPower > 1)
86 {
87 NdArray<double> inArrayDouble = inArray.template astype<double>();
88 NdArray<double> returnArray = dot(inArrayDouble, inArrayDouble);
89 for (int16 i = 2; i < inPower; ++i)
90 {
91 returnArray = dot(returnArray, inArrayDouble);
92 }
93 return returnArray;
94 }
95
96 NdArray<double> inverse = inv(inArray);
97 NdArray<double> returnArray = dot(inverse, inverse);
98 inPower *= -1;
99 for (int16 i = 2; i < inPower; ++i)
100 {
101 returnArray = dot(returnArray, inverse);
102 }
103 return returnArray;
104 }
105} // namespace nc::linalg
#define THROW_INVALID_ARGUMENT_ERROR(msg)
Definition: Error.hpp:37
#define STATIC_ASSERT_ARITHMETIC_OR_COMPLEX(dtype)
Definition: StaticAsserts.hpp:56
const Shape & shape() const noexcept
Definition: NdArrayCore.hpp:4511
A Shape Class for NdArrays.
Definition: Core/Shape.hpp:41
uint32 rows
Definition: Core/Shape.hpp:44
uint32 cols
Definition: Core/Shape.hpp:45
Definition: cholesky.hpp:41
NdArray< double > inv(const NdArray< dtype > &inArray)
Definition: inv.hpp:54
NdArray< double > matrix_power(const NdArray< dtype > &inArray, int16 inPower)
Definition: matrix_power.hpp:60
NdArray< dtype > dot(const NdArray< dtype > &inArray1, const NdArray< dtype > &inArray2)
Definition: dot.hpp:47
std::int16_t int16
Definition: Types.hpp:37