PLearn 0.1
BernoulliSampleVariable.cc
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00001 // -*- C++ -*-
00002 
00003 // BernoulliSampleVariable.cc
00004 //
00005 // Copyright (C) 2007 Pascal Vincent
00006 //
00007 // Redistribution and use in source and binary forms, with or without
00008 // modification, are permitted provided that the following conditions are met:
00009 //
00010 //  1. Redistributions of source code must retain the above copyright
00011 //     notice, this list of conditions and the following disclaimer.
00012 //
00013 //  2. Redistributions in binary form must reproduce the above copyright
00014 //     notice, this list of conditions and the following disclaimer in the
00015 //     documentation and/or other materials provided with the distribution.
00016 //
00017 //  3. The name of the authors may not be used to endorse or promote
00018 //     products derived from this software without specific prior written
00019 //     permission.
00020 //
00021 // THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
00022 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00023 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
00024 // NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00025 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
00026 // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00027 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00028 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00029 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00030 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00031 //
00032 // This file is part of the PLearn library. For more information on the PLearn
00033 // library, go to the PLearn Web site at www.plearn.org
00034 
00035 // Authors: Pascal Vincent
00036 
00040 #include "BernoulliSampleVariable.h"
00041 
00042 namespace PLearn {
00043 using namespace std;
00044 
00047 PLEARN_IMPLEMENT_OBJECT(
00048     BernoulliSampleVariable,
00049     "Input gives a vector of parameters, each of which is the probability parameter of a Bernoulli. Output is sample from those." ,
00050     "\n"
00051     );
00052 
00053 
00055 
00056 BernoulliSampleVariable::BernoulliSampleVariable(Variable* input)
00057     : inherited(input, input->length(), input->width()),
00058       random_gen(0)
00059 {
00060     build_();
00061 }
00062 
00063 void BernoulliSampleVariable::recomputeSize(int& l, int& w) const
00064 {
00065     if (input) {
00066         l = input->length();
00067         w = input->width() ;
00068     } else
00069         l = w = 0;
00070 }
00071 
00072 // ### computes value from input's value
00073 void BernoulliSampleVariable::fprop()
00074 {
00075     checkContiguity();
00076 
00077     if(random_gen.isNull())
00078         random_gen = PRandom::common(false);
00079 
00080     int l = nelems();
00081     real* valueptr = valuedata;
00082     real* inputvalueptr = input->valuedata;
00083     for(int i=0; i<l; i++)
00084         *valueptr++ = random_gen->binomial_sample(*inputvalueptr++);
00085 }
00086 
00087 // ### computes input's gradient from gradient
00088 void BernoulliSampleVariable::bprop()
00089 {}    
00090 
00091 // ### You can implement these methods:
00092 // void BernoulliSampleVariable::bbprop() {}
00093 // void BernoulliSampleVariable::symbolicBprop() {}
00094 // void BernoulliSampleVariable::rfprop() {}
00095 
00096 
00097 // ### Nothing to add here, simply calls build_
00098 void BernoulliSampleVariable::build()
00099 {
00100     inherited::build();
00101     build_();
00102 }
00103 
00104 void BernoulliSampleVariable::makeDeepCopyFromShallowCopy(CopiesMap& copies)
00105 {
00106     inherited::makeDeepCopyFromShallowCopy(copies);
00107 
00108     // ### Call deepCopyField on all "pointer-like" fields
00109     // ### that you wish to be deepCopied rather than
00110     // ### shallow-copied.
00111     // ### ex:
00112     deepCopyField(random_gen, copies);
00113     // ### If you want to deepCopy a Var field:
00114     // varDeepCopyField(somevariable, copies);   
00115 }
00116 
00117 void BernoulliSampleVariable::declareOptions(OptionList& ol)
00118 {
00119     // ### Declare all of this object's options here.
00120     // ### For the "flags" of each option, you should typically specify
00121     // ### one of OptionBase::buildoption, OptionBase::learntoption or
00122     // ### OptionBase::tuningoption. If you don't provide one of these three,
00123     // ### this option will be ignored when loading values from a script.
00124     // ### You can also combine flags, for example with OptionBase::nosave:
00125     // ### (OptionBase::buildoption | OptionBase::nosave)
00126 
00127     // ### ex:
00128     declareOption(ol, "random_gen", &BernoulliSampleVariable::random_gen,
00129                   OptionBase::buildoption,
00130                   "Random number generator. If null, the PRandom::common(false) generator will be used.");
00131             
00132     // Now call the parent class' declareOptions
00133     inherited::declareOptions(ol);
00134 }
00135 
00136 void BernoulliSampleVariable::build_()
00137 {
00138     // ### This method should do the real building of the object,
00139     // ### according to set 'options', in *any* situation.
00140     // ### Typical situations include:
00141     // ###  - Initial building of an object from a few user-specified options
00142     // ###  - Building of a "reloaded" object: i.e. from the complete set of
00143     // ###    all serialised options.
00144     // ###  - Updating or "re-building" of an object after a few "tuning"
00145     // ###    options have been modified.
00146     // ### You should assume that the parent class' build_() has already been
00147     // ### called.
00148 }
00149 
00150 
00151 } // end of namespace PLearn
00152 
00153 
00154 /*
00155   Local Variables:
00156   mode:c++
00157   c-basic-offset:4
00158   c-file-style:"stroustrup"
00159   c-file-offsets:((innamespace . 0)(inline-open . 0))
00160   indent-tabs-mode:nil
00161   fill-column:79
00162   End:
00163 */
00164 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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