PLearn 0.1
LiftBinaryCostFunction.cc
Go to the documentation of this file.
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: LiftBinaryCostFunction.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "LiftBinaryCostFunction.h"
00044 
00045 namespace PLearn {
00046 using namespace std;
00047 
00048 
00049 PLEARN_IMPLEMENT_OBJECT(LiftBinaryCostFunction, "ONE LINE DESCR", "NO HELP");
00050 
00051 real LiftBinaryCostFunction::evaluate(const Vec& output, const Vec& target) const
00052 {
00053     int len = output.length();
00054     if ((target.length()!=1 && target.length()!=2) || len>2)
00055         PLERROR("For binary problems, the output and binary vectors must have length 1 or 2 (%d)", len);
00056 
00057     if (len == 1)
00058     {
00059         real out0 = output[0];
00060         if (make_positive_output) out0 = sigmoid(out0);
00061         return (target[0]>0.5) ? out0 : -out0;
00062     }
00063     else
00064     {
00065         real out1 = output[1];
00066         if (make_positive_output) out1 = sigmoid(out1);
00067         if (target.length()==2)
00068             return (target[1]>target[0]) ? out1 : -out1;
00069         else
00070             return (target[0]>0.5) ? out1 : -out1;
00071     }
00072 
00073     return 0.0;  // to make the compiler happy...
00074 }
00075 
00076 void LiftBinaryCostFunction::declareOptions(OptionList &ol)
00077 {
00078     declareOption(ol, "make_positive_output", &LiftBinaryCostFunction::make_positive_output, OptionBase::buildoption,
00079                   "TODO: Some comments");
00080     inherited::declareOptions(ol);
00081 }
00082 
00083 } // end of namespace PLearn
00084 
00085 
00086 /*
00087   Local Variables:
00088   mode:c++
00089   c-basic-offset:4
00090   c-file-style:"stroustrup"
00091   c-file-offsets:((innamespace . 0)(inline-open . 0))
00092   indent-tabs-mode:nil
00093   fill-column:79
00094   End:
00095 */
00096 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines