PLearn 0.1
TimesVariable.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: TimesVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "TimesVariable.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(TimesVariable,
00054                         "Multiplies 2 matrix vars of same size elementwise", 
00055                         "NO HELP");
00056 
00057 TimesVariable::TimesVariable(Variable* input1, Variable* input2)
00058     : inherited(input1, input2, input1->length(), input1->width())
00059 {
00060     build_();
00061 }
00062 
00063 void
00064 TimesVariable::build()
00065 {
00066     inherited::build();
00067     build_();
00068 }
00069 
00070 void
00071 TimesVariable::build_()
00072 {
00073     if (input1 && input2) {
00074         if(input1->length() != input2->length() || input1->width() != input2->width())
00075             PLERROR("In TimesVariable: input1 and input2 must have exactly the same size");
00076     }
00077 }
00078 
00079 
00080 void TimesVariable::recomputeSize(int& l, int& w) const
00081 {
00082     if (input1 && input2) {
00083         l = input1->length();
00084         w = input1->width();
00085     } else
00086         l = w = 0;
00087 }
00088 
00089 void TimesVariable::fprop()
00090 {
00091     for(int k=0; k<nelems(); k++)
00092         valuedata[k] = input1->valuedata[k]*input2->valuedata[k];
00093 }
00094 
00095 
00096 void TimesVariable::bprop()
00097 {
00098     for(int k=0; k<nelems(); k++)
00099     {
00100         input1->gradientdata[k] += input2->valuedata[k]*gradientdata[k];
00101         input2->gradientdata[k] += input1->valuedata[k]*gradientdata[k];
00102     }
00103 }
00104 
00105 
00106 void TimesVariable::symbolicBprop()
00107 {
00108     input1->accg(g*input2);
00109     input2->accg(g*input1);
00110 }
00111 
00112 
00113 
00114 } // end of namespace PLearn
00115 
00116 
00117 /*
00118   Local Variables:
00119   mode:c++
00120   c-basic-offset:4
00121   c-file-style:"stroustrup"
00122   c-file-offsets:((innamespace . 0)(inline-open . 0))
00123   indent-tabs-mode:nil
00124   fill-column:79
00125   End:
00126 */
00127 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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