PLearn 0.1
VarArrayElementVariable.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: VarArrayElementVariable.cc 3994 2005-08-25 13:35:03Z chapados $
00040  * This file is part of the PLearn library.
00041  ******************************************************* */
00042 
00043 #include "VarArrayElementVariable.h"
00044 
00045 namespace PLearn {
00046 using namespace std;
00047 
00048 
00050 /* selects one element of a VarArray according to a Var index */
00051 
00052 PLEARN_IMPLEMENT_OBJECT(VarArrayElementVariable,
00053                         "Selects one element of a VarArray according to a Var index */",
00054                         "NO HELP");
00055 
00056 VarArrayElementVariable::
00057 VarArrayElementVariable(VarArray& input1, const Var& input2)
00058     : inherited(input1 & (VarArray)input2, input1[0]->length(), input1[0]->width())
00059 {
00060     build_();
00061 }
00062 
00063 void
00064 VarArrayElementVariable::build()
00065 {
00066     inherited::build();
00067     build_();
00068 }
00069 
00070 void
00071 VarArrayElementVariable::build_()
00072 {
00073     if (varray.size() >= 2) {// && varray[0] && varray[1] && varray[1].size()) {
00074         int l = varray[0]->length();
00075         int w = varray[0]->width();
00076         for (int i = 1; i < varray.size() - 1; i++)
00077             if (varray[i]->length() != l || varray[i]->width() != w)
00078                 PLERROR("VarArrayElementVairables expect all the elements of input1 array to have the same size");
00079         if (!varray[varray.size() - 1]->isScalar())
00080             PLERROR("VarArrayElementVariable expect an index Var (input2) of length 1");
00081     }
00082 }
00083 
00084 
00085 void VarArrayElementVariable::recomputeSize(int& l, int& w) const
00086 {
00087     if (varray.size()) {
00088         l = varray[0]->length();
00089         w = varray[0]->width();
00090     } else
00091         l = w = 0;
00092 }
00093 
00094 void VarArrayElementVariable::fprop()
00095 {
00096     int index = (int)(varray.last()->valuedata[0]);
00097 #ifdef BOUNDCHECK
00098     if (index<0 || index>=varray.size()-1)
00099         PLERROR("VarArrayElementVariable::fprop, out of bound access of array(%d) at %d",
00100                 varray.size()-1,index);
00101 #endif
00102     for (int i=0;i<nelems();i++)
00103         valuedata[i] = varray[index]->valuedata[i];
00104 }
00105 
00106 
00107 void VarArrayElementVariable::bprop()
00108 {
00109     int index = (int)(varray.last()->valuedata[0]);
00110     for (int i=0;i<nelems();i++)
00111         varray[index]->gradientdata[i] += gradientdata[i];
00112 }
00113 
00114 
00115 void VarArrayElementVariable::symbolicBprop()
00116 {
00117     int index = (int)(varray.last()->valuedata[0]);
00118     varray[index]->accg(g);
00119 }
00120 
00121 
00122 
00123 } // end of namespace PLearn
00124 
00125 
00126 /*
00127   Local Variables:
00128   mode:c++
00129   c-basic-offset:4
00130   c-file-style:"stroustrup"
00131   c-file-offsets:((innamespace . 0)(inline-open . 0))
00132   indent-tabs-mode:nil
00133   fill-column:79
00134   End:
00135 */
00136 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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