PLearn 0.1
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00001 // -*- C++ -*- 00002 00003 // PLearn (A C++ Machine Learning Library) 00004 // Copyright (C) 1998 Pascal Vincent 00005 // Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio, Rejean Ducharme and University of Montreal 00006 // Copyright (C) 2001-2002 Nicolas Chapados, Ichiro Takeuchi, Jean-Sebastien Senecal 00007 // Copyright (C) 2002 Xiangdong Wang, Christian Dorion 00008 00009 // Redistribution and use in source and binary forms, with or without 00010 // modification, are permitted provided that the following conditions are met: 00011 // 00012 // 1. Redistributions of source code must retain the above copyright 00013 // notice, this list of conditions and the following disclaimer. 00014 // 00015 // 2. Redistributions in binary form must reproduce the above copyright 00016 // notice, this list of conditions and the following disclaimer in the 00017 // documentation and/or other materials provided with the distribution. 00018 // 00019 // 3. The name of the authors may not be used to endorse or promote 00020 // products derived from this software without specific prior written 00021 // permission. 00022 // 00023 // THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 00024 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00025 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN 00026 // NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00027 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 00028 // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 00029 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 00030 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 00031 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 00032 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00033 // 00034 // This file is part of the PLearn library. For more information on the PLearn 00035 // library, go to the PLearn Web site at www.plearn.org 00036 00037 00038 /* ******************************************************* 00039 * $Id: SoftplusVariable.cc 8956 2008-05-08 19:19:03Z tihocan $ 00040 * This file is part of the PLearn library. 00041 ******************************************************* */ 00042 00043 #include "SigmoidVariable.h" 00044 #include "SoftplusVariable.h" 00045 #include "Var_operators.h" 00046 //#include "Var_utils.h" 00047 00048 namespace PLearn { 00049 using namespace std; 00050 00051 00054 PLEARN_IMPLEMENT_OBJECT( 00055 SoftplusVariable, 00056 "This is the primitive of a sigmoid: log(1+exp(x)).", 00057 "" 00058 ); 00059 00061 // SoftplusVariable // 00063 SoftplusVariable::SoftplusVariable(Variable* input, bool call_build_): 00064 inherited(input, input->length(), input->width(), call_build_) 00065 { 00066 if (call_build_) 00067 build_(); 00068 } 00069 00071 // build // 00073 void SoftplusVariable::build() { 00074 inherited::build(); 00075 build_(); 00076 } 00077 00079 // build_ // 00081 void SoftplusVariable::build_() { 00082 // Nothing to do here. 00083 } 00084 00086 // recomputeSize // 00088 void SoftplusVariable::recomputeSize(int& l, int& w) const 00089 { 00090 if (input) { 00091 l = input->length(); 00092 w = input->width(); 00093 } else 00094 l = w = 0; 00095 } 00096 00097 void SoftplusVariable::fprop() 00098 { 00099 for(int i=0; i<nelems(); i++) 00100 valuedata[i] = softplus(input->valuedata[i]); 00101 } 00102 00103 00104 void SoftplusVariable::bprop() 00105 { 00106 for(int i=0; i<nelems(); i++) 00107 input->gradientdata[i] += gradientdata[i] * sigmoid(input->valuedata[i]); 00108 } 00109 00110 00111 void SoftplusVariable::symbolicBprop() 00112 { 00113 Var v(this); 00114 input->accg(g*sigmoid(input)); 00115 } 00116 00117 00118 00119 } // end of namespace PLearn 00120 00121 00122 /* 00123 Local Variables: 00124 mode:c++ 00125 c-basic-offset:4 00126 c-file-style:"stroustrup" 00127 c-file-offsets:((innamespace . 0)(inline-open . 0)) 00128 indent-tabs-mode:nil 00129 fill-column:79 00130 End: 00131 */ 00132 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :