PLearn 0.1
NegateElementsVariable.cc
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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: NegateElementsVariable.cc 8856 2008-04-21 20:57:52Z tihocan $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "NegateElementsVariable.h"
00044 #include "Var_operators.h"
00045 //#include "Var_utils.h"
00046 
00047 namespace PLearn {
00048 using namespace std;
00049 
00050 
00053 PLEARN_IMPLEMENT_OBJECT(
00054         NegateElementsVariable,
00055         "Elementwise negation of the input value.",
00056         ""
00057 );
00058 
00060 // NegateElementsVariable //
00062 NegateElementsVariable::NegateElementsVariable(Variable* input,
00063                                                bool call_build_):
00064     inherited(input, input->length(), input->width(), call_build_)
00065 {
00066     if (call_build_)
00067         build_();
00068 }
00069 
00070 
00072 // build //
00074 void NegateElementsVariable::build()
00075 {
00076     inherited::build();
00077     build_();
00078 }
00079 
00080 
00082 // build_ //
00084 void NegateElementsVariable::build_()
00085 {
00086     // Nothing to do here.
00087 }
00088 
00089 void NegateElementsVariable::recomputeSize(int& l, int& w) const
00090 {
00091     if (input) {
00092         l = input->length();
00093         w = input->width();
00094     } else
00095         l = w = 0;
00096 }
00097 
00098 void NegateElementsVariable::fprop()
00099 {
00100     for(int k=0; k<nelems(); k++)
00101         valuedata[k] = -input->valuedata[k];
00102 }
00103 
00104 
00105 void NegateElementsVariable::bprop()
00106 {
00107     for(int k=0; k<nelems(); k++)
00108         input->gradientdata[k] -= gradientdata[k];
00109 }
00110 
00111 
00112 void NegateElementsVariable::bbprop()
00113 {
00114     if (input->diaghessian.length()==0)
00115         input->resizeDiagHessian();
00116     for(int k=0; k<nelems(); k++)
00117         input->diaghessiandata[k] -= diaghessiandata[k];
00118 }
00119 
00120 
00121 void NegateElementsVariable::symbolicBprop()
00122 {
00123     input->accg(-g);
00124 }
00125 
00126 
00127 // R(-x) = -R(x)
00128 void NegateElementsVariable::rfprop()
00129 {
00130     if (rValue.length()==0) resizeRValue();
00131     for(int k=0; k<nelems(); k++)
00132         rvaluedata[k] = -input->rvaluedata[k];
00133 }
00134 
00135 
00136 
00137 } // end of namespace PLearn
00138 
00139 
00140 /*
00141   Local Variables:
00142   mode:c++
00143   c-basic-offset:4
00144   c-file-style:"stroustrup"
00145   c-file-offsets:((innamespace . 0)(inline-open . 0))
00146   indent-tabs-mode:nil
00147   fill-column:79
00148   End:
00149 */
00150 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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