PLearn 0.1
TimesConstantScalarVariable2.cc
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00001 // -*- C++ -*-
00002 
00003 // TimesConstantScalarVariable2.cc
00004 //
00005 // Copyright (C) 2007 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 
00036 /* *******************************************************      
00037  * $Id: TimesConstantScalarVariable2.cc 3994 2005-08-25 13:35:03Z chapados $
00038  * This file is part of the PLearn library.
00039  ******************************************************* */
00040 
00041 #include "TimesConstantScalarVariable2.h"
00042 #include <plearn/var/Var_operators.h>
00043 
00044 
00045 
00046 namespace PLearn {
00047 using namespace std;
00048 
00051 PLEARN_IMPLEMENT_OBJECT(TimesConstantScalarVariable2,
00052                         "Multiplies the first var V1 by a scalar second var V2. The second var is assumed constant, and no gradient is backpropagated to it.",
00053                         "NO HELP");
00054 
00055 TimesConstantScalarVariable2::TimesConstantScalarVariable2(Variable* input1, Variable* input2)
00056     : inherited(input1, input2, input1->length(), input1->width())
00057 {
00058     build_();
00059 }
00060 
00061 void
00062 TimesConstantScalarVariable2::build()
00063 {
00064     inherited::build();
00065     build_();
00066 }
00067 
00068 void
00069 TimesConstantScalarVariable2::build_()
00070 {
00071     if (input2 && !input2->isScalar())
00072         PLERROR("IN TimesConstantScalarVariable2: input2 is not a scalar");
00073 }
00074 
00075 void TimesConstantScalarVariable2::recomputeSize(int& l, int& w) const
00076 {
00077     if (input1) {
00078         l = input1->length();
00079         w = input1->width();
00080     } else
00081         l = w = 0;
00082 }
00083 
00084 void TimesConstantScalarVariable2::fprop()
00085 {
00086     real scal = input2->valuedata[0];
00087     for(int k=0; k<nelems(); k++)
00088         valuedata[k] = input1->valuedata[k] * scal;
00089 }
00090 
00091 
00092 void TimesConstantScalarVariable2::bprop()
00093 {
00094     real scal = input2->valuedata[0];
00095     for(int k=0; k<nelems(); k++)
00096         input1->gradientdata[k] += scal*gradientdata[k];
00097 }
00098 
00099 
00100 void TimesConstantScalarVariable2::symbolicBprop()
00101 {
00102     input1->accg(g*input2);
00103 }
00104 
00105 
00106 //R(x1x2)=R(x1)x2+x1R(x2)
00107 void TimesConstantScalarVariable2::rfprop()
00108 {
00109     if (rValue.length()==0) resizeRValue();
00110     real scal = input2->valuedata[0];
00111     real rscal = input2->rvaluedata[0];
00112     for(int k=0; k<nelems(); k++)
00113         rvaluedata[k] = input1->rvaluedata[k] * scal + input1->valuedata[k] * rscal;
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 :
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