Logo ROOT   6.30.04
Reference Guide
 All Namespaces Files Pages
LossFunctions.hxx
Go to the documentation of this file.
1 // @(#)root/tmva/tmva/dnn:$Id$
2 // Author: Simon Pfreundschuh 20/07/16
3 
4 /*************************************************************************
5  * Copyright (C) 2016, Simon Pfreundschuh *
6  * All rights reserved. *
7  * *
8  * For the licensing terms see $ROOTSYS/LICENSE. *
9  * For the list of contributors see $ROOTSYS/README/CREDITS. *
10  *************************************************************************/
11 
12  /////////////////////////////////////////////////////////////////////
13  // Implementation of the loss functions for the multi-threaded CPU //
14  // implementation using Roots TThreadExecutor and BLAS. //
15  /////////////////////////////////////////////////////////////////////
16 
17 #include "TMVA/DNN/Architectures/Reference.h"
18 #include "TMVA/DNN/Architectures/Cpu.h"
19 
20 namespace TMVA
21 {
22 namespace DNN
23 {
24 
25 //______________________________________________________________________________
26 template <typename AFloat>
27 AFloat TCpu<AFloat>::MeanSquaredError(const TCpuMatrix<AFloat> &Y, const TCpuMatrix<AFloat> &output,
28  const TCpuMatrix<AFloat> &weights)
29 {
30  const AFloat *dataY = Y.GetRawDataPointer();
31  const AFloat *dataOutput = output.GetRawDataPointer();
32  const AFloat *dataWeights = weights.GetRawDataPointer();
33  std::vector<AFloat> temp(Y.GetNoElements());
34  size_t m = Y.GetNrows();
35  AFloat norm = 1.0 / ((AFloat) Y.GetNrows() * Y.GetNcols());
36 
37  auto f = [&dataY, &dataOutput, &dataWeights, &temp, m](UInt_t workerID) {
38  AFloat dy = dataY[workerID] - dataOutput[workerID];
39  temp[workerID] = dataWeights[workerID % m] * dy * dy;
40  return 0;
41  };
42 
43  auto reduction = [](const std::vector<AFloat> & v )
44  {
45  return std::accumulate(v.begin(),v.end(),AFloat{});
46  };
47 
48  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNoElements()));
49  return norm * Y.GetThreadExecutor().Reduce(temp, reduction);
50 }
51 
52 //______________________________________________________________________________
53 template <typename AFloat>
54 void TCpu<AFloat>::MeanSquaredErrorGradients(TCpuMatrix<AFloat> &dY, const TCpuMatrix<AFloat> &Y,
55  const TCpuMatrix<AFloat> &output, const TCpuMatrix<AFloat> &weights)
56 {
57 
58  AFloat *dataDY = dY.GetRawDataPointer();
59  const AFloat *dataY = Y.GetRawDataPointer();
60  const AFloat *dataOutput = output.GetRawDataPointer();
61  const AFloat *dataWeights = weights.GetRawDataPointer();
62 
63  size_t m = Y.GetNrows();
64  AFloat norm = 1.0 / ((AFloat) Y.GetNrows() * Y.GetNcols());
65 
66  auto f = [&dataDY, &dataY, &dataOutput, &dataWeights, m, norm](UInt_t workerID) {
67  dataDY[workerID] = -2.0 * norm * (dataY[workerID] - dataOutput[workerID]);
68  dataDY[workerID] *= dataWeights[workerID % m];
69  return 0;
70  };
71 
72  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNoElements()));
73 }
74 
75 //______________________________________________________________________________
76 template <typename AFloat>
77 AFloat TCpu<AFloat>::CrossEntropy(const TCpuMatrix<AFloat> &Y, const TCpuMatrix<AFloat> &output,
78  const TCpuMatrix<AFloat> &weights)
79 {
80  const AFloat *dataY = Y.GetRawDataPointer();
81  const AFloat *dataOutput = output.GetRawDataPointer();
82  const AFloat *dataWeights = weights.GetRawDataPointer();
83  std::vector<AFloat> temp(Y.GetNoElements());
84 
85  size_t m = Y.GetNrows();
86  AFloat norm = 1.0 / ((AFloat) Y.GetNrows() * Y.GetNcols());
87 
88  auto f = [&dataY, &dataOutput, &dataWeights, &temp, m](UInt_t workerID) {
89  AFloat y = dataY[workerID];
90  AFloat sig = 1.0 / (1.0 + exp(- dataOutput[workerID]));
91  if (y == 0)
92  temp[workerID] = - log(1.0 - sig);
93  else if ( y == 1.)
94  temp[workerID] = - log(sig);
95  else
96  temp[workerID] = - (y * log(sig) + (1.0 - y) * log(1.0 - sig));
97 
98  temp[workerID] *= dataWeights[workerID % m];
99  return 0;
100  };
101 
102  auto reduction = [](const std::vector<AFloat> & v )
103  {
104  return std::accumulate(v.begin(),v.end(),AFloat{});
105  };
106 
107  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNoElements()));
108  return norm * Y.GetThreadExecutor().Reduce(temp, reduction);
109 }
110 
111 //______________________________________________________________________________
112 template <typename AFloat>
113 void TCpu<AFloat>::CrossEntropyGradients(TCpuMatrix<AFloat> &dY, const TCpuMatrix<AFloat> &Y,
114  const TCpuMatrix<AFloat> &output, const TCpuMatrix<AFloat> &weights)
115 {
116  AFloat *dataDY = dY.GetRawDataPointer();
117  const AFloat *dataY = Y.GetRawDataPointer();
118  const AFloat *dataOutput = output.GetRawDataPointer();
119  const AFloat *dataWeights = weights.GetRawDataPointer();
120 
121  size_t m = Y.GetNrows();
122  AFloat norm = 1.0 / ((AFloat) Y.GetNrows() * Y.GetNcols());
123 
124  auto f = [&dataDY, &dataY, &dataOutput, &dataWeights, m, norm](UInt_t workerID) {
125  AFloat y = dataY[workerID];
126  AFloat sig = 1.0 / (1.0 + exp(- dataOutput[workerID]));
127  dataDY[workerID] = norm * (sig - y);
128  dataDY[workerID] *= dataWeights[workerID % m];
129  return 0;
130  };
131 
132  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNoElements()));
133 }
134 
135 //______________________________________________________________________________
136 template <typename AFloat>
137 AFloat TCpu<AFloat>::SoftmaxCrossEntropy(const TCpuMatrix<AFloat> &Y, const TCpuMatrix<AFloat> &output,
138  const TCpuMatrix<AFloat> &weights)
139 {
140  const AFloat *dataY = Y.GetRawDataPointer();
141  const AFloat *dataOutput = output.GetRawDataPointer();
142  const AFloat *dataWeights = weights.GetRawDataPointer();
143 
144  std::vector<AFloat> temp(Y.GetNrows());
145  size_t m = Y.GetNrows();
146  size_t n = Y.GetNcols();
147  AFloat norm = 1.0 / ((AFloat) m);
148 
149  auto f = [&dataY, &dataOutput, &dataWeights, &temp, n, m](UInt_t workerID) {
150  AFloat sum = 0.0;
151  for (size_t j = 0; j < n; j++) {
152  sum += exp(dataOutput[workerID + j * m]);
153  }
154  for (size_t j = 0; j < n; j++) {
155  temp[workerID] -=
156  dataY[workerID + j * m] * log(exp(dataOutput[workerID + j * m]) / sum);
157  }
158  temp[workerID] *= dataWeights[workerID];
159  return 0;
160  };
161 
162  auto reduction = [](const std::vector<AFloat> & v )
163  {
164  return std::accumulate(v.begin(),v.end(),AFloat{});
165  };
166 
167  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNrows()));
168  return norm * Y.GetThreadExecutor().Reduce(temp, reduction);
169 }
170 
171 //______________________________________________________________________________
172 template <typename AFloat>
173 void TCpu<AFloat>::SoftmaxCrossEntropyGradients(TCpuMatrix<AFloat> &dY, const TCpuMatrix<AFloat> &Y,
174  const TCpuMatrix<AFloat> &output, const TCpuMatrix<AFloat> &weights)
175 {
176  AFloat *dataDY = dY.GetRawDataPointer();
177  const AFloat *dataY = Y.GetRawDataPointer();
178  const AFloat *dataOutput = output.GetRawDataPointer();
179  const AFloat *dataWeights = weights.GetRawDataPointer();
180 
181  size_t m = Y.GetNrows();
182  size_t n = Y.GetNcols();
183  AFloat norm = 1.0 / ((AFloat) m);
184 
185  auto f = [&dataDY, &dataY, &dataOutput, &dataWeights, norm, n, m](UInt_t workerID) {
186  AFloat sum = 0.0;
187  AFloat sumY = 0.0;
188  AFloat weight = dataWeights[workerID];
189  for (size_t j = 0; j < n; j++) {
190  sum += exp(dataOutput[workerID + j * m]);
191  sumY += dataY[workerID + j * m];
192  }
193  for (size_t j = 0; j < n; j++) {
194  dataDY[workerID + j * m] =
195  norm * (exp(dataOutput[workerID + j * m]) / sum * sumY - dataY[workerID + j * m]);
196  dataDY[workerID + j * m] *= weight;
197  }
198  return 0;
199  };
200 
201  Y.GetThreadExecutor().Map(f, ROOT::TSeqI(Y.GetNrows()));
202 }
203 
204 } // namespace DNN
205 } // namespace TMVA