PLearn 0.1
PlusConstantVariable.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: PlusConstantVariable.cc 8956 2008-05-08 19:19:03Z tihocan $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "PlusConstantVariable.h"
00044 
00045 namespace PLearn {
00046 using namespace std;
00047 
00048 
00051 PLEARN_IMPLEMENT_OBJECT(
00052         PlusConstantVariable,
00053         "Adds a scalar constant to a matrix Variable.",
00054         ""
00055 );
00056 
00058 // PlusConstantVariable //
00060 PlusConstantVariable::PlusConstantVariable():
00061     cst(0)
00062 {}
00063 
00064 PlusConstantVariable::PlusConstantVariable(Variable* input, real c,
00065                                            bool call_build_):
00066     inherited(input, input->length(), input->width(), call_build_),
00067     cst(c)
00068 {
00069     if (call_build_)
00070         build_();
00071 }
00072 
00074 // build //
00076 void PlusConstantVariable::build() {
00077     inherited::build();
00078     build_();
00079 }
00080 
00082 // build_ //
00084 void PlusConstantVariable::build_() {
00085     // Nothing to do here.
00086 }
00087 
00089 // declareOptions //
00091 void PlusConstantVariable::declareOptions(OptionList &ol)
00092 {
00093     inherited::declareOptions(ol);
00094     declareOption(ol, "cst", &PlusConstantVariable::cst,
00095                   OptionBase::buildoption,
00096         "The constant to be added.");
00097 }
00098 
00099 void PlusConstantVariable::recomputeSize(int& l, int& w) const
00100 {
00101     if (input) {
00102         l = input->length();
00103         w = input->width();
00104     } else
00105         l = w = 0;
00106 }
00107 
00108 void PlusConstantVariable::fprop()
00109 {
00110     for(int k=0; k<nelems(); k++)
00111         valuedata[k] = input->valuedata[k] + cst;
00112 }
00113 
00114 
00115 void PlusConstantVariable::bprop()
00116 {
00117     for(int k=0; k<nelems(); k++)
00118         input->gradientdata[k] += gradientdata[k];
00119 }
00120 
00121 
00122 void PlusConstantVariable::symbolicBprop()
00123 {
00124     input->accg(g);
00125 }
00126 
00127 
00128 // R(x+c) = R(x)
00129 void PlusConstantVariable::rfprop()
00130 {
00131     if (rValue.length()==0) resizeRValue();
00132     for(int k=0; k<nelems(); k++)
00133         rvaluedata[k] = input->rvaluedata[k];
00134 }
00135 
00136 
00137 
00138 } // end of namespace PLearn
00139 
00140 
00141 /*
00142   Local Variables:
00143   mode:c++
00144   c-basic-offset:4
00145   c-file-style:"stroustrup"
00146   c-file-offsets:((innamespace . 0)(inline-open . 0))
00147   indent-tabs-mode:nil
00148   fill-column:79
00149   End:
00150 */
00151 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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