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Iir.h
1#ifndef STK_IIR_H
2#define STK_IIR_H
3
4#include "Filter.h"
5
6namespace stk {
7
8/***************************************************/
32/***************************************************/
33
34 class Iir : public Filter
35{
36public:
38 Iir( void );
39
41
45 Iir( std::vector<StkFloat> &bCoefficients, std::vector<StkFloat> &aCoefficients );
46
48 ~Iir( void );
49
51
58 void setCoefficients( std::vector<StkFloat> &bCoefficients, std::vector<StkFloat> &aCoefficients, bool clearState = false );
59
61
68 void setNumerator( std::vector<StkFloat> &bCoefficients, bool clearState = false );
69
71
80 void setDenominator( std::vector<StkFloat> &aCoefficients, bool clearState = false );
81
83 StkFloat lastOut( void ) const { return lastFrame_[0]; };
84
86 StkFloat tick( StkFloat input );
87
89
97 StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
98
100
108 StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
109
110protected:
111
112};
113
114 inline StkFloat Iir :: tick( StkFloat input )
115{
116 size_t i;
117
118 outputs_[0] = 0.0;
119 inputs_[0] = gain_ * input;
120 for ( i=b_.size()-1; i>0; i-- ) {
121 outputs_[0] += b_[i] * inputs_[i];
122 inputs_[i] = inputs_[i-1];
123 }
124 outputs_[0] += b_[0] * inputs_[0];
125
126 for ( i=a_.size()-1; i>0; i-- ) {
127 outputs_[0] += -a_[i] * outputs_[i];
128 outputs_[i] = outputs_[i-1];
129 }
130
131 lastFrame_[0] = outputs_[0];
132 return lastFrame_[0];
133}
134
135 inline StkFrames& Iir :: tick( StkFrames& frames, unsigned int channel )
136{
137#if defined(_STK_DEBUG_)
138 if ( channel >= frames.channels() ) {
139 oStream_ << "Iir::tick(): channel and StkFrames arguments are incompatible!";
140 handleError( StkError::FUNCTION_ARGUMENT );
141 }
142#endif
143
144 StkFloat *samples = &frames[channel];
145 size_t i;
146 unsigned int hop = frames.channels();
147 for ( unsigned int j=0; j<frames.frames(); j++, samples += hop ) {
148 outputs_[0] = 0.0;
149 inputs_[0] = gain_ * *samples;
150 for ( i=b_.size()-1; i>0; i-- ) {
151 outputs_[0] += b_[i] * inputs_[i];
152 inputs_[i] = inputs_[i-1];
153 }
154 outputs_[0] += b_[0] * inputs_[0];
155
156 for ( i=a_.size()-1; i>0; i-- ) {
157 outputs_[0] += -a_[i] * outputs_[i];
158 outputs_[i] = outputs_[i-1];
159 }
160
161 *samples = outputs_[0];
162 }
163
164 lastFrame_[0] = *(samples-hop);
165 return frames;
166}
167
168 inline StkFrames& Iir :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
169{
170#if defined(_STK_DEBUG_)
171 if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
172 oStream_ << "Iir::tick(): channel and StkFrames arguments are incompatible!";
173 handleError( StkError::FUNCTION_ARGUMENT );
174 }
175#endif
176
177 StkFloat *iSamples = &iFrames[iChannel];
178 StkFloat *oSamples = &oFrames[oChannel];
179 size_t i;
180 unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
181 for ( unsigned int j=0; j<iFrames.frames(); j++, iSamples += iHop, oSamples += oHop ) {
182 outputs_[0] = 0.0;
183 inputs_[0] = gain_ * *iSamples;
184 for ( i=b_.size()-1; i>0; i-- ) {
185 outputs_[0] += b_[i] * inputs_[i];
186 inputs_[i] = inputs_[i-1];
187 }
188 outputs_[0] += b_[0] * inputs_[0];
189
190 for ( i=a_.size()-1; i>0; i-- ) {
191 outputs_[0] += -a_[i] * outputs_[i];
192 outputs_[i] = outputs_[i-1];
193 }
194
195 *oSamples = outputs_[0];
196 }
197
198 lastFrame_[0] = *(oSamples-oHop);
199 return iFrames;
200}
201
202} // stk namespace
203
204#endif
stk::Filter
STK abstract filter class.
Definition Filter.h:23
stk::Iir
STK general infinite impulse response filter class.
Definition Iir.h:35
stk::Iir::lastOut
StkFloat lastOut(void) const
Return the last computed output value.
Definition Iir.h:83
stk::Iir::Iir
Iir(void)
Default constructor creates a zero-order pass-through "filter".
stk::Iir::setNumerator
void setNumerator(std::vector< StkFloat > &bCoefficients, bool clearState=false)
Set numerator coefficients.
stk::Iir::tick
StkFloat tick(StkFloat input)
Input one sample to the filter and return one output.
Definition Iir.h:114
stk::Iir::setCoefficients
void setCoefficients(std::vector< StkFloat > &bCoefficients, std::vector< StkFloat > &aCoefficients, bool clearState=false)
Set filter coefficients.
stk::Iir::Iir
Iir(std::vector< StkFloat > &bCoefficients, std::vector< StkFloat > &aCoefficients)
Overloaded constructor which takes filter coefficients.
stk::Iir::~Iir
~Iir(void)
Class destructor.
stk::Iir::setDenominator
void setDenominator(std::vector< StkFloat > &aCoefficients, bool clearState=false)
Set denominator coefficients.
stk::StkFrames
An STK class to handle vectorized audio data.
Definition Stk.h:279
stk::StkFrames::channels
unsigned int channels(void) const
Return the number of channels represented by the data.
Definition Stk.h:416
stk::StkFrames::frames
unsigned int frames(void) const
Return the number of sample frames represented by the data.
Definition Stk.h:419
stk
The STK namespace.
Definition ADSR.h:6

The Synthesis ToolKit in C++ (STK)
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