PLearn 0.1
ArgmaxVariable.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: ArgmaxVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "ArgmaxVariable.h"
00044 
00045 namespace PLearn {
00046 using namespace std;
00047 
00048 
00051 PLEARN_IMPLEMENT_OBJECT(ArgmaxVariable,
00052                         "Compute the index of the maximum value in the input",
00053                         "NO HELP");
00054 
00055 ArgmaxVariable::ArgmaxVariable(Variable* input)
00056     : inherited(input, input->isVec()?1:2, 1)
00057 {}
00058 
00059 
00060 void ArgmaxVariable::recomputeSize(int& l, int& w) const
00061 {
00062     if (input)
00063         l = input->isVec() ? 1 : 2;
00064     w = 1;
00065 }
00066 
00067 void ArgmaxVariable::fprop()
00068 {
00069     real maxval = input->valuedata[0];
00070     if (input->isVec())
00071     {
00072         int argmax = 0;
00073         for(int i=1; i<input->nelems(); i++)
00074         {
00075             real val = input->valuedata[i];
00076             if(val>maxval)
00077             {
00078                 maxval = val;
00079                 argmax = i;
00080             }
00081         }
00082         valuedata[0] = argmax;
00083     }
00084     else
00085     {
00086         int k = 0;
00087         int argmax_i = 0;
00088         int argmax_j = 0;
00089         for(int i=0; i<input->length(); i++)
00090             for(int j=0; j<input->width(); j++, k++)
00091             {
00092                 real val = input->valuedata[k];
00093                 if(val>maxval)
00094                 {
00095                     maxval = val;
00096                     argmax_i = i;
00097                     argmax_j = j;
00098                 }
00099             }
00100         valuedata[0] = argmax_i;
00101         valuedata[1] = argmax_j;
00102     }
00103 }
00104 
00105 
00106 void ArgmaxVariable::bprop() {}
00107 
00108 void ArgmaxVariable::symbolicBprop() {}
00109 
00110 
00111 
00112 } // end of namespace PLearn
00113 
00114 
00115 /*
00116   Local Variables:
00117   mode:c++
00118   c-basic-offset:4
00119   c-file-style:"stroustrup"
00120   c-file-offsets:((innamespace . 0)(inline-open . 0))
00121   indent-tabs-mode:nil
00122   fill-column:79
00123   End:
00124 */
00125 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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