PLearn 0.1
SquaredErrorCostFunction.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: SquaredErrorCostFunction.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "SelectedOutputCostFunction.h"
00044 #include "SquaredErrorCostFunction.h"
00045 
00046 namespace PLearn {
00047 using namespace std;
00048 
00049 
00050 PLEARN_IMPLEMENT_OBJECT(SquaredErrorCostFunction, "ONE LINE DESCR", "NO HELP");
00051 
00052 real SquaredErrorCostFunction::evaluate(const Vec& output, const Vec& target) const
00053 {
00054 #ifdef BOUNDCHECK
00055     if(target.length()!=output.length() && classification==false)
00056         PLERROR("In SquaredErrorCostFunction::evaluate target.length() %d should be equal to output.length() %d",target.length(),output.length());
00057 #endif
00058 
00059     real result = 0.0;
00060     if (targetindex>=0)
00061         result = square(output[targetindex]-target[targetindex]);
00062     else
00063     {
00064         real* outputdata = output.data();
00065         real* targetdata = target.data();
00066         if (classification) {
00067             if (target.length() != 1)
00068                 PLERROR("In SquaredErrorCostFunction::evaluate target.length() %s should be 1", target.length());
00069 
00070             for (int i = 0; i < output.length(); ++i)
00071                 if (i == targetdata[0])
00072                     result += square(outputdata[i] - hotvalue);
00073                 else
00074                     result += square(outputdata[i] - coldvalue);
00075         } else {
00076             for(int i=0; i<output.length(); i++)
00077                 result += square(outputdata[i]-targetdata[i]);
00078         }
00079     }
00080     return result;
00081 }
00082 
00083 void SquaredErrorCostFunction::declareOptions(OptionList &ol)
00084 {
00085     declareOption(ol, "targetindex", &SquaredErrorCostFunction::targetindex, OptionBase::buildoption, "Index of target");
00086     declareOption(ol, "hotvalue", &SquaredErrorCostFunction::hotvalue, OptionBase::buildoption, "Hot value");
00087     declareOption(ol, "coldvalue", &SquaredErrorCostFunction::coldvalue, OptionBase::buildoption, "Cold value");
00088     declareOption(ol, "classification", &SquaredErrorCostFunction::classification, OptionBase::buildoption, "Used as classification cost");
00089     inherited::declareOptions(ol);
00090 }
00091 
00092 CostFunc squared_error(int singleoutputindex)
00093 { 
00094     if(singleoutputindex>=0)
00095         return new SelectedOutputCostFunction(new SquaredErrorCostFunction(),singleoutputindex); 
00096     else
00097         return new SquaredErrorCostFunction();
00098 }
00099 
00100 } // end of namespace PLearn
00101 
00102 
00103 /*
00104   Local Variables:
00105   mode:c++
00106   c-basic-offset:4
00107   c-file-style:"stroustrup"
00108   c-file-offsets:((innamespace . 0)(inline-open . 0))
00109   indent-tabs-mode:nil
00110   fill-column:79
00111   End:
00112 */
00113 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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