PLearn 0.1
SaltPepperNoiseVariable.cc
Go to the documentation of this file.
00001 // -*- C++ -*-
00002 
00003 // SaltPepperNoiseVariable.cc
00004 //
00005 // Copyright (C) 2009 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 "SaltPepperNoiseVariable.h"
00041 
00042 namespace PLearn {
00043 using namespace std;
00044 
00047 PLEARN_IMPLEMENT_OBJECT(
00048     SaltPepperNoiseVariable,
00049     "ONE LINE USER DESCRIPTION",
00050     "MULTI LINE\nHELP FOR USERS"
00051     );
00052 
00053 SaltPepperNoiseVariable::SaltPepperNoiseVariable()
00054     :corruption_prob(0),
00055      pepper_prob(0.5),
00056      salt_value(0),
00057      pepper_value(1)
00058 {
00059     // ### You may (or not) want to call build_() to finish building the object
00060     // ### (doing so assumes the parent classes' build_() have been called too
00061     // ### in the parent classes' constructors, something that you must ensure)
00062 }
00063 
00064 // constructor from input variable and parameters
00065 // SaltPepperNoiseVariable::SaltPepperNoiseVariable(Variable* input, param_type the_parameter,...)
00066 // ### replace with actual parameters
00067 //  : inherited(input, this_variable_length, this_variable_width),
00068 //    parameter(the_parameter),
00069 //    ...
00070 //{
00071 //    // ### You may (or not) want to call build_() to finish building the
00072 //    // ### object
00073 //}
00074 
00075 void SaltPepperNoiseVariable::recomputeSize(int& l, int& w) const
00076 {
00077     if (input) 
00078     {
00079         l = input.length();
00080         w = input.width(); // the computed width
00081     } 
00082     else
00083         l = w = 0;
00084 }
00085 
00086 // ### computes value from input's value
00087 void SaltPepperNoiseVariable::fprop()
00088 {
00089     checkContiguity();
00090 
00091     if(random_gen.isNull())
00092         random_gen = PRandom::common(false);
00093 
00094 
00095     int n = value.length();
00096     corrupted.resize(n);
00097 
00098     for(int i=0; i<n; i++)
00099     {
00100         if(random_gen->uniform_sample()<corruption_prob)
00101         {
00102             if(random_gen->uniform_sample()<pepper_prob)
00103                 valuedata[i] = pepper_value;
00104             else
00105                 valuedata[i] = salt_value;
00106 
00107             corrupted[i] = true;
00108         }
00109         else
00110         {
00111             valuedata[i] = input->valuedata[i];
00112             corrupted[i] = false;
00113         }
00114     }
00115 }
00116 
00117 // ### computes input's gradient from gradient
00118 void SaltPepperNoiseVariable::bprop()
00119 {
00120     int n = gradient.length();
00121     for(int i=0; i<n; i++)
00122     {
00123         if(!corrupted[i])
00124             input->gradientdata[i] += gradientdata[i];
00125     }
00126 }
00127 
00128 // ### You can implement these methods:
00129 // void SaltPepperNoiseVariable::bbprop() {}
00130 // void SaltPepperNoiseVariable::symbolicBprop() {}
00131 // void SaltPepperNoiseVariable::rfprop() {}
00132 
00133 
00134 // ### Nothing to add here, simply calls build_
00135 void SaltPepperNoiseVariable::build()
00136 {
00137     inherited::build();
00138     build_();
00139 }
00140 
00141 void SaltPepperNoiseVariable::makeDeepCopyFromShallowCopy(CopiesMap& copies)
00142 {
00143     inherited::makeDeepCopyFromShallowCopy(copies);
00144 
00145     // ### Call deepCopyField on all "pointer-like" fields
00146     // ### that you wish to be deepCopied rather than
00147     // ### shallow-copied.
00148     // ### ex:
00149     deepCopyField(random_gen, copies);
00150 
00151     // ### If you want to deepCopy a Var field:
00152     // varDeepCopyField(somevariable, copies);
00153 }
00154 
00155 void SaltPepperNoiseVariable::declareOptions(OptionList& ol)
00156 {
00157     // ### Declare all of this object's options here.
00158     // ### For the "flags" of each option, you should typically specify
00159     // ### one of OptionBase::buildoption, OptionBase::learntoption or
00160     // ### OptionBase::tuningoption. If you don't provide one of these three,
00161     // ### this option will be ignored when loading values from a script.
00162     // ### You can also combine flags, for example with OptionBase::nosave:
00163     // ### (OptionBase::buildoption | OptionBase::nosave)
00164 
00165     declareOption(ol, "corruption_prob", &SaltPepperNoiseVariable::corruption_prob,
00166                   OptionBase::buildoption,
00167                   "The probability of corrupting each input element");
00168     declareOption(ol, "pepper_prob", &SaltPepperNoiseVariable::pepper_prob,
00169                   OptionBase::buildoption,
00170                   "If an element is to be corrupted, it will be set to pepper_value with probability pepper_prob and to salt_value with probability 1-pepper_prob.");
00171     declareOption(ol, "salt_value", &SaltPepperNoiseVariable::salt_value,
00172                   OptionBase::buildoption,
00173                   "The value to which to set all inputs that have been elected to be corrupted to salt.");
00174     declareOption(ol, "pepper_value", &SaltPepperNoiseVariable::pepper_value,
00175                   OptionBase::buildoption,
00176                   "The value to which to set all inputs that have been elected to be corrupted to pepper.");
00177     declareOption(ol, "random_gen", &SaltPepperNoiseVariable::random_gen,
00178                   OptionBase::buildoption,
00179                   "Random number generator. If null, the PRandom::common(false) generator will be used.");
00180 
00181     // Now call the parent class' declareOptions
00182     inherited::declareOptions(ol);
00183 }
00184 
00185 void SaltPepperNoiseVariable::build_()
00186 {
00187     // ### This method should do the real building of the object,
00188     // ### according to set 'options', in *any* situation.
00189     // ### Typical situations include:
00190     // ###  - Initial building of an object from a few user-specified options
00191     // ###  - Building of a "reloaded" object: i.e. from the complete set of
00192     // ###    all serialised options.
00193     // ###  - Updating or "re-building" of an object after a few "tuning"
00194     // ###    options have been modified.
00195     // ### You should assume that the parent class' build_() has already been
00196     // ### called.
00197 }
00198 
00199 
00200 } // end of namespace PLearn
00201 
00202 
00203 /*
00204   Local Variables:
00205   mode:c++
00206   c-basic-offset:4
00207   c-file-style:"stroustrup"
00208   c-file-offsets:((innamespace . 0)(inline-open . 0))
00209   indent-tabs-mode:nil
00210   fill-column:79
00211   End:
00212 */
00213 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines