PLearn 0.1
SoftmaxVariable.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: SoftmaxVariable.h 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #ifndef SoftmaxVariable_INC
00044 #define SoftmaxVariable_INC
00045 
00046 #include "UnaryVariable.h"
00047 #include "MatrixSoftmaxVariable.h"
00048 
00049 namespace PLearn {
00050 using namespace std;
00051 
00052 
00053 class SoftmaxVariable: public UnaryVariable
00054 {
00055     typedef UnaryVariable inherited;
00056 
00057 public:
00059     SoftmaxVariable() {}
00060     SoftmaxVariable(Variable* input);
00061 
00062     PLEARN_DECLARE_OBJECT(SoftmaxVariable);
00063 
00064     virtual void recomputeSize(int& l, int& w) const;
00065     virtual void fprop();
00066     virtual void bprop();
00067     virtual void bbprop();
00068     virtual void symbolicBprop();
00069     virtual void rfprop();
00070 };
00071 
00072 DECLARE_OBJECT_PTR(SoftmaxVariable);
00073 
00074 // Now we have a special box!
00075 inline Var softmax(Var v)
00076 {
00077     if(v->isVec()) 
00078         return new SoftmaxVariable(v);
00079     else return new MatrixSoftmaxVariable(v);
00080 }
00081 
00082 //* OLD implementation 
00083 /*
00084   inline Var old_softmax(Var input)
00085   { 
00087   Var maxin = max(input);
00088   Var exp_input = exp(input-maxin);
00089   return exp_input/sum(exp_input); 
00090   }
00091 */
00092 
00093 
00094 } // end of namespace PLearn
00095 
00096 #endif 
00097 
00098 
00099 /*
00100   Local Variables:
00101   mode:c++
00102   c-basic-offset:4
00103   c-file-style:"stroustrup"
00104   c-file-offsets:((innamespace . 0)(inline-open . 0))
00105   indent-tabs-mode:nil
00106   fill-column:79
00107   End:
00108 */
00109 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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