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: AbsVariable.cc 3994 2005-08-25 13:35:03Z chapados $ 00040 * This file is part of the PLearn library. 00041 ******************************************************* */ 00042 00043 #include "AbsVariable.h" 00044 #include "IfThenElseVariable.h" 00045 #include "IsAboveThresholdVariable.h" 00046 #include "Var_operators.h" 00047 00048 namespace PLearn { 00049 using namespace std; 00050 00051 00052 00055 PLEARN_IMPLEMENT_OBJECT( 00056 AbsVariable, 00057 "Variable whose output is the absolute value of its input", 00058 ""); 00059 00060 AbsVariable::AbsVariable(Variable* input) 00061 : inherited(input, input->length(), input->width()) 00062 {} 00063 00064 00065 void AbsVariable::recomputeSize(int& l, int& w) const 00066 { 00067 if (input) { 00068 l = input->length(); 00069 w = input->width(); 00070 } else 00071 l = w = 0; 00072 } 00073 00074 void AbsVariable::fprop() 00075 { 00076 for(int i=0; i<nelems(); i++) 00077 { 00078 real val = input->valuedata[i]; 00079 valuedata[i] = val>=0 ?val :-val; 00080 } 00081 } 00082 00083 00084 void AbsVariable::bprop() 00085 { 00086 for(int i=0; i<nelems(); i++) 00087 { 00088 real val = input->valuedata[i]; 00089 if(val>=0) 00090 input->gradientdata[i] += gradientdata[i]; 00091 else 00092 input->gradientdata[i] -= gradientdata[i]; 00093 } 00094 } 00095 00096 00097 void AbsVariable::symbolicBprop() 00098 { 00099 input->accg(ifThenElse(input >= 0., g, -g)); 00100 } 00101 00102 00103 // R{abs(x)} = R(x) while x >= 0 00104 // R{abs(x)} = -R(x) while x < 0 00105 void AbsVariable::rfprop() 00106 { 00107 if (rValue.length()==0) resizeRValue(); 00108 int n=nelems(); 00109 for(int i=0; i<n; i++) 00110 if (input->valuedata[i] < 0) 00111 rvaluedata[i] = -input->rvaluedata[i]; 00112 else 00113 rvaluedata[i] = input->rvaluedata[i]; 00114 } 00115 00116 00117 00118 } // end of namespace PLearn 00119 00120 00121 /* 00122 Local Variables: 00123 mode:c++ 00124 c-basic-offset:4 00125 c-file-style:"stroustrup" 00126 c-file-offsets:((innamespace . 0)(inline-open . 0)) 00127 indent-tabs-mode:nil 00128 fill-column:79 00129 End: 00130 */ 00131 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :