PLearn 0.1
UnaryHardSlopeVariable.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: UnaryHardSlopeVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "UnaryHardSlopeVariable.h"
00044 #include "Var_operators.h"
00045 
00046 namespace PLearn {
00047 using namespace std;
00048 
00049 
00052 PLEARN_IMPLEMENT_OBJECT(UnaryHardSlopeVariable, 
00053                         "Hard slope function whose Var input is only the argument of the function.", 
00054                         "Maps x (elementwise) to 0 if x<left, 1 if x>right, and linear in between otherwise.");
00055 
00056 UnaryHardSlopeVariable::UnaryHardSlopeVariable()
00057     : left(0), right(0), inv_slope(0)
00058 { }
00059   
00060 UnaryHardSlopeVariable::UnaryHardSlopeVariable(Variable* input,real l,real r) 
00061     : inherited(input, input->length(), input->width()) ,
00062       left(l), right(r), inv_slope(1.0/(r-l))
00063 {}
00064 
00065 void
00066 UnaryHardSlopeVariable::build()
00067 {
00068     inherited::build();
00069     build_();
00070 }
00071 
00072 void
00073 UnaryHardSlopeVariable::build_()
00074 {
00075     inv_slope = (1.0 / (right - 1));
00076 }
00077 
00078 void
00079 UnaryHardSlopeVariable::declareOptions(OptionList &ol)
00080 {
00081     declareOption(ol, "left", &UnaryHardSlopeVariable::left, OptionBase::buildoption, "");
00082     declareOption(ol, "right", &UnaryHardSlopeVariable::right, OptionBase::buildoption, "");
00083     inherited::declareOptions(ol);
00084 }
00085 
00086 void UnaryHardSlopeVariable::recomputeSize(int& l, int& w) const
00087 {
00088     if (input) {
00089         l = input->length();
00090         w = input->width();
00091     } else
00092         l = w = 0;
00093 }
00094 
00095 
00096 void UnaryHardSlopeVariable::fprop()
00097 {
00098     int l = nelems();
00099     real* inputptr = input->valuedata;
00100     real* ptr = valuedata;
00101     for(int i=0; i<l; i++)
00102         *ptr++ = hard_slope(*inputptr++,left,right);
00103 }
00104 
00105 
00106 void UnaryHardSlopeVariable::bprop()
00107 {
00108     int l = nelems();
00109     real* inputgradientptr = input->gradientdata;
00110     real* gradientptr = gradientdata;
00111     real* valueptr = valuedata;
00112     for(int i=0; i<l; i++)
00113     {
00114         real x = *valueptr++;
00115         if (x>left)
00116             if (x<right)
00117                 *inputgradientptr++ += *gradientptr++ * inv_slope;
00118     }
00119 }
00120 
00121 
00122 } // end of namespace PLearn
00123 
00124 
00125 /*
00126   Local Variables:
00127   mode:c++
00128   c-basic-offset:4
00129   c-file-style:"stroustrup"
00130   c-file-offsets:((innamespace . 0)(inline-open . 0))
00131   indent-tabs-mode:nil
00132   fill-column:79
00133   End:
00134 */
00135 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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