NumCpp  2.10.1
A Templatized Header Only C++ Implementation of the Python NumPy Library
bincount.hpp
Go to the documentation of this file.
1 #pragma once
29 
30 #include <string>
31 
35 #include "NumCpp/Core/Types.hpp"
36 #include "NumCpp/NdArray.hpp"
37 
38 namespace nc
39 {
40  //============================================================================
41  // Method Description:
57  template<typename dtype>
58  NdArray<dtype> bincount(const NdArray<dtype>& inArray, uint16 inMinLength = 1)
59  {
60  STATIC_ASSERT_INTEGER(dtype);
61 
62  dtype maxValue = inArray.max().item();
63  if (maxValue < 0)
64  {
65  // no positive values so just return an empty array
66  return NdArray<dtype>(0);
67  }
68 
69  if (maxValue + 1 > DtypeInfo<dtype>::max())
70  {
72  "array values too large, will result in gigantic array that will take up alot of memory...");
73  }
74 
75  const uint16 outArraySize = std::max(static_cast<uint16>(maxValue + 1), inMinLength);
76  NdArray<dtype> clippedArray = inArray.clip(0, maxValue);
77 
78  NdArray<dtype> outArray(1, outArraySize);
79  outArray.zeros();
80  std::for_each(clippedArray.cbegin(),
81  clippedArray.cend(),
82  [&outArray](dtype value) noexcept -> void { ++outArray[value]; });
83 
84  return outArray;
85  }
86 
87  //============================================================================
88  // Method Description:
107  template<typename dtype>
108  NdArray<dtype> bincount(const NdArray<dtype>& inArray, const NdArray<dtype>& inWeights, uint16 inMinLength = 1)
109  {
110  STATIC_ASSERT_INTEGER(dtype);
111 
112  if (inArray.shape() != inWeights.shape())
113  {
114  THROW_INVALID_ARGUMENT_ERROR("weights array must be the same shape as the input array.");
115  }
116 
117  dtype maxValue = inArray.max().item();
118  if (maxValue < 0)
119  {
120  // no positive values so just return an empty array
121  return NdArray<dtype>(0);
122  }
123 
124  if (maxValue + 1 > DtypeInfo<dtype>::max())
125  {
127  "array values too large, will result in gigantic array that will take up alot of memory...");
128  }
129 
130  const uint16 outArraySize = std::max(static_cast<uint16>(maxValue + 1), inMinLength);
131  NdArray<dtype> clippedArray = inArray.clip(0, maxValue);
132 
133  NdArray<dtype> outArray(1, outArraySize);
134  outArray.zeros();
135  uint32 counter = 0;
136  std::for_each(clippedArray.cbegin(),
137  clippedArray.cend(),
138  [&outArray, &inWeights, &counter](dtype value) noexcept -> void
139  { outArray[value] += inWeights[counter++]; });
140 
141  return outArray;
142  }
143 } // namespace nc
#define THROW_INVALID_ARGUMENT_ERROR(msg)
Definition: Error.hpp:37
#define STATIC_ASSERT_INTEGER(dtype)
Definition: StaticAsserts.hpp:43
Holds info about the dtype.
Definition: DtypeInfo.hpp:41
Holds 1D and 2D arrays, the main work horse of the NumCpp library.
Definition: NdArrayCore.hpp:138
self_type max(Axis inAxis=Axis::NONE) const
Definition: NdArrayCore.hpp:2964
self_type & zeros() noexcept
Definition: NdArrayCore.hpp:4793
const_iterator cbegin() const noexcept
Definition: NdArrayCore.hpp:1308
Shape shape() const noexcept
Definition: NdArrayCore.hpp:4402
const_iterator cend() const noexcept
Definition: NdArrayCore.hpp:1616
value_type item() const
Definition: NdArrayCore.hpp:2945
self_type clip(value_type inMin, value_type inMax) const
Definition: NdArrayCore.hpp:2316
void for_each(InputIt first, InputIt last, UnaryFunction f)
Definition: StlAlgorithms.hpp:225
Definition: Coordinate.hpp:45
NdArray< dtype > max(const NdArray< dtype > &inArray, Axis inAxis=Axis::NONE)
Definition: max.hpp:44
NdArray< dtype > bincount(const NdArray< dtype > &inArray, uint16 inMinLength=1)
Definition: bincount.hpp:58
std::uint16_t uint16
Definition: Types.hpp:41
std::uint32_t uint32
Definition: Types.hpp:40