PLearn 0.1
SquaredErrorCostFunction.h
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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.h 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #ifndef SquaredErrorCostFunction_INC
00044 #define SquaredErrorCostFunction_INC
00045 
00046 #include "Kernel.h"
00047 
00048 namespace PLearn {
00049 using namespace std;
00050 
00053 
00054 
00055 class SquaredErrorCostFunction: public Kernel
00056 {
00057     typedef Kernel inherited;
00058                 
00059 protected:
00062     int targetindex;
00063     bool classification;
00064     real hotvalue, coldvalue;
00065 
00066 public:
00067     SquaredErrorCostFunction(int the_targetindex=-1)
00068         :targetindex(the_targetindex), classification(false), hotvalue(1), coldvalue(0) {};
00069 
00071     SquaredErrorCostFunction(real hot_value, real cold_value)
00072         : targetindex(-1), classification(true), hotvalue(hot_value), coldvalue(cold_value) {};
00073 
00074     PLEARN_DECLARE_OBJECT(SquaredErrorCostFunction);
00075 
00076     virtual string info() const
00077     { return "squared_error"; }
00078 
00079     virtual real evaluate(const Vec& output, const Vec& target) const; 
00080 
00081 protected:
00083     static void declareOptions(OptionList &ol);
00084 };
00085 
00086 DECLARE_OBJECT_PTR(SquaredErrorCostFunction);
00087 
00088 inline CostFunc squared_classification_error(real hot_value=0.8, real cold_value=0.2)
00089 {
00090     return new SquaredErrorCostFunction(hot_value, cold_value);
00091 }
00092 
00093 inline CostFunc squared_error(int singleoutputindex=-1);
00094 
00095 } // end of namespace PLearn
00096 
00097 #endif
00098 
00099 
00100 /*
00101   Local Variables:
00102   mode:c++
00103   c-basic-offset:4
00104   c-file-style:"stroustrup"
00105   c-file-offsets:((innamespace . 0)(inline-open . 0))
00106   indent-tabs-mode:nil
00107   fill-column:79
00108   End:
00109 */
00110 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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