PLearn 0.1
TimesConstantVariable.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: TimesConstantVariable.h 9099 2008-06-03 21:58:54Z plearner $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #ifndef TimesConstantVariable_INC
00044 #define TimesConstantVariable_INC
00045 
00046 #include "UnaryVariable.h"
00047 #include <plearn/base/stringutils.h>    
00048 
00049 namespace PLearn {
00050 using namespace std;
00051 
00052 
00053 
00056 
00057 class TimesConstantVariable: public UnaryVariable
00058 {
00059     typedef UnaryVariable inherited;
00060 
00061 public:
00062 //protected:
00063     real cst; 
00064 
00065 public:
00067     TimesConstantVariable() : cst() {}
00068     TimesConstantVariable(Variable* input, real c);
00069 
00070     PLEARN_DECLARE_OBJECT(TimesConstantVariable);
00071 
00072 
00073     virtual string info() const
00074     { return string("TimesConstant (* ")+tostring(cst)+")"; }
00075 
00076     virtual void recomputeSize(int& l, int& w) const;
00077     virtual void fprop();
00078     virtual void bprop();
00079     virtual void symbolicBprop();
00080     virtual void rfprop();
00081 
00082 protected:
00083 
00084     static void declareOptions(OptionList &ol);
00085 };
00086 
00087 DECLARE_OBJECT_PTR(TimesConstantVariable);
00088 
00089 inline Var operator*(Var v, real cte)
00090 { 
00091     if(cte==1)
00092         return v;
00093     else
00094         return new TimesConstantVariable(v,cte); 
00095 }
00096 
00097 inline Var operator*(real cte, Var v)
00098 { return v*cte; }
00099 
00100 inline Var operator/(Var v, real cte)
00101 { return v*(1.0/cte); }
00102 
00103 
00104 } // end of namespace PLearn
00105 
00106 #endif 
00107 
00108 
00109 /*
00110   Local Variables:
00111   mode:c++
00112   c-basic-offset:4
00113   c-file-style:"stroustrup"
00114   c-file-offsets:((innamespace . 0)(inline-open . 0))
00115   indent-tabs-mode:nil
00116   fill-column:79
00117   End:
00118 */
00119 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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