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112 lines
3.6 KiB
C++
112 lines
3.6 KiB
C++
#ifndef STK_JETTABL_H
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#define STK_JETTABL_H
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#include "Function.h"
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namespace stk {
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/***************************************************/
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/*! \class JetTable
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\brief STK jet table class.
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This class implements a flue jet non-linear
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function, computed by a polynomial calculation.
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Contrary to the name, this is not a "table".
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Consult Fletcher and Rossing, Karjalainen,
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Cook, and others for more information.
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by Perry R. Cook and Gary P. Scavone, 1995-2012.
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*/
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/***************************************************/
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class JetTable : public Function
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{
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public:
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//! Take one sample input and map to one sample of output.
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StkFloat tick( StkFloat input );
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//! Take a channel of the StkFrames object as inputs to the table and replace with corresponding outputs.
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/*!
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The StkFrames argument reference is returned. The \c channel
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argument must be less than the number of channels in the
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StkFrames argument (the first channel is specified by 0).
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However, range checking is only performed if _STK_DEBUG_ is
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defined during compilation, in which case an out-of-range value
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will trigger an StkError exception.
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*/
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StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
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//! Take a channel of the \c iFrames object as inputs to the table and write outputs to the \c oFrames object.
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/*!
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The \c iFrames object reference is returned. Each channel
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argument must be less than the number of channels in the
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corresponding StkFrames argument (the first channel is specified
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by 0). However, range checking is only performed if _STK_DEBUG_
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is defined during compilation, in which case an out-of-range value
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will trigger an StkError exception.
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*/
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StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
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};
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inline StkFloat JetTable :: tick( StkFloat input )
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{
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// Perform "table lookup" using a polynomial
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// calculation (x^3 - x), which approximates
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// the jet sigmoid behavior.
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lastFrame_[0] = input * (input * input - 1.0);
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// Saturate at +/- 1.0.
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if ( lastFrame_[0] > 1.0 ) lastFrame_[0] = 1.0;
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if ( lastFrame_[0] < -1.0 ) lastFrame_[0] = -1.0;
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return lastFrame_[0];
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}
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inline StkFrames& JetTable :: tick( StkFrames& frames, unsigned int channel )
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{
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#if defined(_STK_DEBUG_)
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if ( channel >= frames.channels() ) {
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oStream_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
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handleError( StkError::FUNCTION_ARGUMENT );
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}
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#endif
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StkFloat *samples = &frames[channel];
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unsigned int hop = frames.channels();
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for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
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*samples = *samples * (*samples * *samples - 1.0);
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if ( *samples > 1.0) *samples = 1.0;
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if ( *samples < -1.0) *samples = -1.0;
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}
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lastFrame_[0] = *(samples-hop);
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return frames;
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}
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inline StkFrames& JetTable :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
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{
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#if defined(_STK_DEBUG_)
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if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
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oStream_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
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handleError( StkError::FUNCTION_ARGUMENT );
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}
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#endif
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StkFloat *iSamples = &iFrames[iChannel];
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StkFloat *oSamples = &oFrames[oChannel];
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unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
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for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
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*oSamples = *oSamples * (*oSamples * *oSamples - 1.0);
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if ( *oSamples > 1.0) *oSamples = 1.0;
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if ( *oSamples < -1.0) *oSamples = -1.0;
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}
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lastFrame_[0] = *(oSamples-oHop);
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return iFrames;
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}
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} // stk namespace
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#endif
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