NumCpp  2.7.0
A Templatized Header Only C++ Implementation of the Python NumPy Library
stdev.hpp
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1 #pragma once
29 
30 #include "NumCpp/Core/Types.hpp"
32 #include "NumCpp/NdArray.hpp"
33 #include "NumCpp/Utils/sqr.hpp"
34 
35 #include <algorithm>
36 #include <cmath>
37 #include <complex>
38 
39 namespace nc
40 {
41  //============================================================================
42  // Method Description:
51  template<typename dtype>
52  NdArray<double> stdev(const NdArray<dtype>& inArray, Axis inAxis = Axis::NONE)
53  {
55 
56  double meanValue = 0.0;
57  double sum = 0.0;
58 
59  const auto function = [&sum, &meanValue](dtype value) -> void
60  {
61  sum += utils::sqr(static_cast<double>(value) - meanValue);
62  };
63 
64  switch (inAxis)
65  {
66  case Axis::NONE:
67  {
68  meanValue = mean(inArray, inAxis).item();
69  std::for_each(inArray.cbegin(), inArray.cend(), function);
70 
71  NdArray<double> returnArray = { std::sqrt(sum / inArray.size()) };
72  return returnArray;
73  }
74  case Axis::COL:
75  {
76  NdArray<double> meanValueArray = mean(inArray, inAxis);
77  NdArray<double> returnArray(1, inArray.numRows());
78  for (uint32 row = 0; row < inArray.numRows(); ++row)
79  {
80  meanValue = meanValueArray[row];
81  sum = 0.0;
82  std::for_each(inArray.cbegin(row), inArray.cend(row), function);
83 
84  returnArray(0, row) = std::sqrt(sum / inArray.numCols());
85  }
86 
87  return returnArray;
88  }
89  case Axis::ROW:
90  {
91  NdArray<double> meanValueArray = mean(inArray, inAxis);
92  NdArray<dtype> transposedArray = inArray.transpose();
93  NdArray<double> returnArray(1, transposedArray.numRows());
94  for (uint32 row = 0; row < transposedArray.numRows(); ++row)
95  {
96  meanValue = meanValueArray[row];
97  sum = 0.0;
98  std::for_each(transposedArray.cbegin(row), transposedArray.cend(row), function);
99 
100  returnArray(0, row) = std::sqrt(sum / transposedArray.numCols());
101  }
102 
103  return returnArray;
104  }
105  default:
106  {
107  THROW_INVALID_ARGUMENT_ERROR("Unimplemented axis type.");
108  return {}; // get rid of compiler warning
109  }
110  }
111  }
112 
113  //============================================================================
114  // Method Description:
123  template<typename dtype>
124  NdArray<std::complex<double>> stdev(const NdArray<std::complex<dtype>>& inArray, Axis inAxis = Axis::NONE)
125  {
127 
128  std::complex<double> meanValue(0.0, 0.0);
129  std::complex<double> sum(0.0, 0.0);
130 
131  const auto function = [&sum, &meanValue](std::complex<dtype> value) -> void
132  {
133  sum += utils::sqr(complex_cast<double>(value) - meanValue);
134  };
135 
136  switch (inAxis)
137  {
138  case Axis::NONE:
139  {
140  meanValue = mean(inArray, inAxis).item();
141  std::for_each(inArray.cbegin(), inArray.cend(), function);
142 
143  NdArray<std::complex<double>> returnArray = { std::sqrt(sum / static_cast<double>(inArray.size())) };
144  return returnArray;
145  }
146  case Axis::COL:
147  {
148  NdArray<std::complex<double>> meanValueArray = mean(inArray, inAxis);
149  NdArray<std::complex<double>> returnArray(1, inArray.numRows());
150  for (uint32 row = 0; row < inArray.numRows(); ++row)
151  {
152  meanValue = meanValueArray[row];
153  sum = std::complex<double>(0.0, 0.0);
154  std::for_each(inArray.cbegin(row), inArray.cend(row), function);
155 
156  returnArray(0, row) = std::sqrt(sum / static_cast<double>(inArray.numCols()));
157  }
158 
159  return returnArray;
160  }
161  case Axis::ROW:
162  {
163  NdArray<std::complex<double>> meanValueArray = mean(inArray, inAxis);
164  NdArray<std::complex<dtype>> transposedArray = inArray.transpose();
165  NdArray<std::complex<double>> returnArray(1, transposedArray.numRows());
166  for (uint32 row = 0; row < transposedArray.numRows(); ++row)
167  {
168  meanValue = meanValueArray[row];
169  sum = std::complex<double>(0.0, 0.0);
170  std::for_each(transposedArray.cbegin(row), transposedArray.cend(row), function);
171 
172  returnArray(0, row) = std::sqrt(sum / static_cast<double>(transposedArray.numCols()));
173  }
174 
175  return returnArray;
176  }
177  default:
178  {
179  THROW_INVALID_ARGUMENT_ERROR("Unimplemented axis type.");
180  return {}; // get rid of compiler warning
181  }
182  }
183  }
184 } // namespace nc
#define THROW_INVALID_ARGUMENT_ERROR(msg)
Definition: Error.hpp:36
#define STATIC_ASSERT_ARITHMETIC(dtype)
Definition: StaticAsserts.hpp:37
uint32 numCols() const noexcept
Definition: NdArrayCore.hpp:3418
size_type size() const noexcept
Definition: NdArrayCore.hpp:4296
const_iterator cbegin() const noexcept
Definition: NdArrayCore.hpp:1216
uint32 numRows() const noexcept
Definition: NdArrayCore.hpp:3430
NdArray< dtype > transpose() const
Definition: NdArrayCore.hpp:4629
const_iterator cend() const noexcept
Definition: NdArrayCore.hpp:1524
value_type item() const
Definition: NdArrayCore.hpp:2931
void for_each(InputIt first, InputIt last, UnaryFunction f)
Definition: StlAlgorithms.hpp:213
constexpr dtype sqr(dtype inValue) noexcept
Definition: sqr.hpp:44
Definition: Coordinate.hpp:45
Axis
Enum To describe an axis.
Definition: Types.hpp:46
auto sqrt(dtype inValue) noexcept
Definition: sqrt.hpp:48
NdArray< dtype > sum(const NdArray< dtype > &inArray, Axis inAxis=Axis::NONE)
Definition: sum.hpp:46
NdArray< double > stdev(const NdArray< dtype > &inArray, Axis inAxis=Axis::NONE)
Definition: stdev.hpp:52
NdArray< double > mean(const NdArray< dtype > &inArray, Axis inAxis=Axis::NONE)
Definition: mean.hpp:52
std::uint32_t uint32
Definition: Types.hpp:40