PLearn 0.1
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00001 // -*- C++ -*- 00002 00003 // SumEntropyOfCategoricals.cc 00004 // 00005 // Copyright (C) 2009 Pascal Vincent 00006 // 00007 // Redistribution and use in source and binary forms, with or without 00008 // modification, are permitted provided that the following conditions are met: 00009 // 00010 // 1. Redistributions of source code must retain the above copyright 00011 // notice, this list of conditions and the following disclaimer. 00012 // 00013 // 2. Redistributions in binary form must reproduce the above copyright 00014 // notice, this list of conditions and the following disclaimer in the 00015 // documentation and/or other materials provided with the distribution. 00016 // 00017 // 3. The name of the authors may not be used to endorse or promote 00018 // products derived from this software without specific prior written 00019 // permission. 00020 // 00021 // THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 00022 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00023 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN 00024 // NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00025 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 00026 // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 00027 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 00028 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 00029 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 00030 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00031 // 00032 // This file is part of the PLearn library. For more information on the PLearn 00033 // library, go to the PLearn Web site at www.plearn.org 00034 00035 // Authors: Pascal Vincent 00036 00040 #include "SumEntropyOfCategoricals.h" 00041 00042 namespace PLearn { 00043 using namespace std; 00044 00047 PLEARN_IMPLEMENT_OBJECT( 00048 SumEntropyOfCategoricals, 00049 "Computes the sum of the entropies of independent categorical variables (multinomials with number-of-trials n=1) whose probability parameters are given as input.", 00050 "i.e. if input is a matrix P, computes sum_ij - [P_ij log(P_ij)].\n" 00051 "Note that this formula does not depend on whether the parameters in P are those of a single categorical variable \n" 00052 "or represent the parameters of several independent categorical variables." 00053 ); 00054 00055 SumEntropyOfCategoricals::SumEntropyOfCategoricals() 00056 : inherited(0, 1, 1) 00057 { 00058 } 00059 00060 // constructor from input variable. 00061 SumEntropyOfCategoricals::SumEntropyOfCategoricals(Variable* input) 00062 : inherited(input, 1, 1) 00063 { 00064 build_(); 00065 } 00066 00067 // constructor from input variable and parameters 00068 // SumEntropyOfCategoricals::SumEntropyOfCategoricals(Variable* input, param_type the_parameter,...) 00069 // ### replace with actual parameters 00070 // : inherited(input, this_variable_length, this_variable_width), 00071 // parameter(the_parameter), 00072 // ... 00073 //{ 00074 // // ### You may (or not) want to call build_() to finish building the 00075 // // ### object 00076 //} 00077 00078 void SumEntropyOfCategoricals::recomputeSize(int& l, int& w) const 00079 { 00080 l = w = 1; 00081 } 00082 00083 // ### computes value from input's value 00084 void SumEntropyOfCategoricals::fprop() 00085 { 00086 double res = 0; 00087 Mat P = input->matValue; 00088 int l = P.length(); 00089 int w = P.width(); 00090 00091 for(int i=0; i<l; i++) 00092 { 00093 const real* P_i = P[i]; 00094 for(int j=0; j<w; j++) 00095 { 00096 real P_ij = P_i[j]; 00097 if( P_ij>1e-25 ) 00098 res += P_ij*pl_log(P_ij); 00099 } 00100 } 00101 valuedata[0] = -(real)res; 00102 } 00103 00104 // ### computes input's gradient from gradient 00105 void SumEntropyOfCategoricals::bprop() 00106 { 00107 /* 00108 [-p log(p)]' = -[log(p) + 1] 00109 */ 00110 real gr = gradientdata[0]; 00111 Mat P = input->matValue; 00112 Mat Pgr = input->matGradient; 00113 00114 int l = P.length(); 00115 int w = P.width(); 00116 00117 for(int i=0; i<l; i++) 00118 { 00119 const real* P_i = P[i]; 00120 real* Pgr_i = Pgr[i]; 00121 for(int j=0; j<w; j++) 00122 { 00123 real P_ij = P_i[j]; 00124 real logPij = P_ij>1e-25 ?pl_log(P_ij): -57.5; 00125 Pgr_i[j] -= gr*(logPij + 1); 00126 } 00127 } 00128 } 00129 00130 // ### You can implement these methods: 00131 // void SumEntropyOfCategoricals::bbprop() {} 00132 // void SumEntropyOfCategoricals::symbolicBprop() {} 00133 // void SumEntropyOfCategoricals::rfprop() {} 00134 00135 00136 // ### Nothing to add here, simply calls build_ 00137 void SumEntropyOfCategoricals::build() 00138 { 00139 inherited::build(); 00140 build_(); 00141 } 00142 00143 void SumEntropyOfCategoricals::makeDeepCopyFromShallowCopy(CopiesMap& copies) 00144 { 00145 inherited::makeDeepCopyFromShallowCopy(copies); 00146 } 00147 00148 void SumEntropyOfCategoricals::declareOptions(OptionList& ol) 00149 { 00150 // ### Declare all of this object's options here. 00151 // ### For the "flags" of each option, you should typically specify 00152 // ### one of OptionBase::buildoption, OptionBase::learntoption or 00153 // ### OptionBase::tuningoption. If you don't provide one of these three, 00154 // ### this option will be ignored when loading values from a script. 00155 // ### You can also combine flags, for example with OptionBase::nosave: 00156 // ### (OptionBase::buildoption | OptionBase::nosave) 00157 00158 // ### ex: 00159 // declareOption(ol, "myoption", &SumEntropyOfCategoricals::myoption, 00160 // OptionBase::buildoption, 00161 // "Help text describing this option"); 00162 // ... 00163 00164 // Now call the parent class' declareOptions 00165 inherited::declareOptions(ol); 00166 } 00167 00168 void SumEntropyOfCategoricals::build_() 00169 { 00170 // ### This method should do the real building of the object, 00171 // ### according to set 'options', in *any* situation. 00172 // ### Typical situations include: 00173 // ### - Initial building of an object from a few user-specified options 00174 // ### - Building of a "reloaded" object: i.e. from the complete set of 00175 // ### all serialised options. 00176 // ### - Updating or "re-building" of an object after a few "tuning" 00177 // ### options have been modified. 00178 // ### You should assume that the parent class' build_() has already been 00179 // ### called. 00180 } 00181 00182 00183 } // end of namespace PLearn 00184 00185 00186 /* 00187 Local Variables: 00188 mode:c++ 00189 c-basic-offset:4 00190 c-file-style:"stroustrup" 00191 c-file-offsets:((innamespace . 0)(inline-open . 0)) 00192 indent-tabs-mode:nil 00193 fill-column:79 00194 End: 00195 */ 00196 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :