PLearn 0.1
VarRowsVariable.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: VarRowsVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "VarRowsVariable.h"
00044 
00045 namespace PLearn {
00046 using namespace std;
00047 
00048 
00051 PLEARN_IMPLEMENT_OBJECT(VarRowsVariable,
00052                         "Variable that is a subset of a matrix's rows; "
00053                         "input1 : matrix from which rows are selected; "
00054                         "input2 : vector whose elements are row indices in input1",
00055                         "NO HELP");
00056 
00057 VarRowsVariable::VarRowsVariable(Variable *input1, Variable *input2)
00058     : inherited(input1, input2, input2->length(), input1->width())
00059 {
00060     build_();
00061 }
00062 
00063 void
00064 VarRowsVariable::build()
00065 {
00066     inherited::build();
00067     build_();
00068 }
00069 
00070 void
00071 VarRowsVariable::build_()
00072 {
00073     if (input1)
00074         input1->allowPartialUpdates();
00075 }
00076 
00077 void VarRowsVariable::recomputeSize(int& l, int& w) const
00078 {
00079     if (input1 && input2) {
00080         l = input2->length();
00081         w = input1->width();
00082     } else
00083         l = w = 0;
00084 }
00085 
00086 void VarRowsVariable::fprop()
00087 {
00088     matValue << input1->matValue.rows(input2->value);
00089 }
00090 
00091 
00092 void VarRowsVariable::bprop()
00093 {
00094     for (int i = 0; i < input2->length(); ++i)
00095     {
00096         int r=int(input2->value[i]);
00097         input1->matGradient.row(r) += matGradient.row(i);
00098         input1->updateRow(r);
00099     }
00100 }
00101 
00102 
00103 void VarRowsVariable::symbolicBprop()
00104 {
00105     PLERROR("VarRowsVariable::symbolicBprop() not implemented");
00106 }
00107 
00108 
00109 
00110 } // end of namespace PLearn
00111 
00112 
00113 /*
00114   Local Variables:
00115   mode:c++
00116   c-basic-offset:4
00117   c-file-style:"stroustrup"
00118   c-file-offsets:((innamespace . 0)(inline-open . 0))
00119   indent-tabs-mode:nil
00120   fill-column:79
00121   End:
00122 */
00123 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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