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