PLearn 0.1
VarRowVariable.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: VarRowVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "VarRowVariable.h"
00044 #include "RowAtPositionVariable.h"
00045 
00046 namespace PLearn {
00047 using namespace std;
00048 
00051 PLEARN_IMPLEMENT_OBJECT(VarRowVariable,
00052                         "Variable that is the row of the input1 variable indexed by the input2 variable",
00053                         "NO HELP");
00054 
00055 VarRowVariable::VarRowVariable(Variable* input1, Variable* input2)
00056     : inherited(input1, input2, 1, input1->width())
00057 {
00058     build_();
00059 }
00060 
00061 void
00062 VarRowVariable::build()
00063 {
00064     inherited::build();
00065     build_();
00066 }
00067 
00068 void
00069 VarRowVariable::build_()
00070 {
00071     if (input1 && input2) {
00072         if (!input2->isScalar())
00073             PLERROR("IN VarRowVariable(Variable* input1, Variable* input2) input2 must be scalar as it is supposed to be an integer index");
00074         input1->allowPartialUpdates();
00075     }
00076 }
00077 
00078 
00079 void VarRowVariable::recomputeSize(int& l, int& w) const
00080 {
00081     l = 1;
00082     if (input1)
00083         w = input1->width();
00084     else
00085         w = 0;
00086 }
00087 
00088 void VarRowVariable::fprop()
00089 {
00090     int i = int(input2->valuedata[0]);
00091     value << input1->matValue(i);
00092 }
00093 
00094 
00095 void VarRowVariable::bprop()
00096 {
00097     int i = int(input2->valuedata[0]);
00098     Vec input1_gradient_i = input1->matGradient(i);
00099     input1_gradient_i += gradient;
00100     input1->updateRow(i);
00101 }
00102 
00103 
00104 void VarRowVariable::symbolicBprop()
00105 {
00106     input1->accg(new RowAtPositionVariable(g,input2,input1->length()));
00107 }
00108 
00109 
00110 void VarRowVariable::rfprop()
00111 {
00112     if (rValue.length()==0) resizeRValue(); 
00113     int i = int(input2->valuedata[0]);
00114     rValue << input1->matRValue(i);
00115 }
00116 
00117 
00118 
00119 } // end of namespace PLearn
00120 
00121 
00122 /*
00123   Local Variables:
00124   mode:c++
00125   c-basic-offset:4
00126   c-file-style:"stroustrup"
00127   c-file-offsets:((innamespace . 0)(inline-open . 0))
00128   indent-tabs-mode:nil
00129   fill-column:79
00130   End:
00131 */
00132 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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