Coefficients.hpp File Reference

Digital filter coefficient design for MayaFlux::Kinesis. More...

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Classes
struct	MayaFlux::Kinesis::Discrete::Biquad
	Second order section with a[0] normalised to 1, returned by value. More...

Namespaces
namespace	MayaFlux
	Main namespace for the Maya Flux audio engine.
namespace	MayaFlux::Kinesis
namespace	MayaFlux::Kinesis::Discrete

Functions
std::vector< double >	MayaFlux::Kinesis::Discrete::backward_difference_weights (size_t order)
	Weights of the backward difference of a given order.
void	MayaFlux::Kinesis::Discrete::biquad_allpass (double frequency, double q, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order allpass coefficients.
Biquad	MayaFlux::Kinesis::Discrete::biquad_bandpass (double frequency, double q, double sample_rate) noexcept
	Constant peak gain bandpass section, returned by value.
void	MayaFlux::Kinesis::Discrete::biquad_bandpass (double frequency, double q, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order bandpass coefficients, constant 0 dB peak gain.
void	MayaFlux::Kinesis::Discrete::biquad_high_shelf (double frequency, double slope, double gain_db, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order high shelf coefficients.
void	MayaFlux::Kinesis::Discrete::biquad_highpass (double frequency, double q, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order highpass coefficients.
void	MayaFlux::Kinesis::Discrete::biquad_low_shelf (double frequency, double slope, double gain_db, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order low shelf coefficients.
void	MayaFlux::Kinesis::Discrete::biquad_lowpass (double frequency, double q, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order lowpass coefficients.
void	MayaFlux::Kinesis::Discrete::biquad_notch (double frequency, double q, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order notch coefficients.
void	MayaFlux::Kinesis::Discrete::biquad_peaking (double frequency, double q, double gain_db, double sample_rate, std::vector< double > &a, std::vector< double > &b)
	Second-order peaking coefficients.
std::vector< double >	MayaFlux::Kinesis::Discrete::cascade (std::span< const double > lhs, std::span< const double > rhs)
	Polynomial product of two coefficient vectors.
void	MayaFlux::Kinesis::Discrete::dc_block (double pole, std::vector< double > &a, std::vector< double > &b)
	DC blocking filter.
double	MayaFlux::Kinesis::Discrete::decay_from_pole_radius (double radius, double sample_rate) noexcept
	Time for an impulse response of a given pole radius to fall by 1/e.
double	MayaFlux::Kinesis::Discrete::decay_from_q (double frequency, double q, double sample_rate) noexcept
	Ring time of a bandpass section of a given Q.
double	MayaFlux::Kinesis::Discrete::decay_per_sample (double seconds, double sample_rate) noexcept
	Per-sample factor that falls by 1/e in a given time.
std::vector< double >	MayaFlux::Kinesis::Discrete::geometric_weights (size_t count, double ratio, bool unit_sum=false)
	Weights that fall by a constant ratio with age.
std::vector< double >	MayaFlux::Kinesis::Discrete::lagrange_delay (double delay, size_t order)
	Lagrange fractional-delay FIR coefficients.
void	MayaFlux::Kinesis::Discrete::lagrange_weights (double delay, std::span< double > weights) noexcept
	Lagrange interpolation weights written to an array, without allocating.
double	MayaFlux::Kinesis::Discrete::max_pole_magnitude (std::span< const double > a)
	Largest pole magnitude of a denominator polynomial.
std::vector< double >	MayaFlux::Kinesis::Discrete::moving_average_weights (size_t count)
	Equal weights summing to 1: Taper::rectangular scaled by 1 / count.
void	MayaFlux::Kinesis::Discrete::one_pole (double pole, std::vector< double > &a, std::vector< double > &b)
	One-pole filter specified by pole position.
double	MayaFlux::Kinesis::Discrete::pole_radius_from_decay (double seconds, double sample_rate) noexcept
	Pole radius whose impulse response falls by 1/e in a given time.
double	MayaFlux::Kinesis::Discrete::q_from_decay (double frequency, double seconds, double sample_rate) noexcept
	Q that gives the bandpass section a stated ring time.
void	MayaFlux::Kinesis::Discrete::resonator (double pole_radius, double pole_angle, std::vector< double > &a, std::vector< double > &b)
	Two-pole resonator specified by z-plane pole position.
std::vector< double >	MayaFlux::Kinesis::Discrete::savitzky_golay (size_t window, size_t poly_order, size_t derivative=0)
	Savitzky-Golay FIR coefficients for smoothing or differentiation.
std::vector< double >	MayaFlux::Kinesis::Discrete::sinc_bandpass (double low_hz, double high_hz, double sample_rate, size_t taps)
	Windowed-sinc bandpass FIR coefficients.
std::vector< double >	MayaFlux::Kinesis::Discrete::sinc_highpass (double frequency, double sample_rate, size_t taps)
	Windowed-sinc highpass FIR coefficients.
std::vector< double >	MayaFlux::Kinesis::Discrete::sinc_lowpass (double frequency, double sample_rate, size_t taps)
	Windowed-sinc lowpass FIR coefficients.

Detailed Description

Digital filter coefficient design for MayaFlux::Kinesis.

Pure numerical functions producing difference-equation coefficient vectors. No MayaFlux type dependencies. Domain-agnostic: the resulting coefficients describe a recurrence over any sampled sequence, not specifically audio.

All biquad designs follow the RBJ Audio EQ Cookbook bilinear transform and are normalised so that a[0] == 1.0 on return. Coefficients are written into caller-supplied vectors, which are resized to the required order.

Convention matches the direct-form recurrence: y[n] = sum(b[i] * x[n-i]) - sum(a[i] * y[n-i]) for i >= 1

SIMD notes: Design functions are scalar and called at configuration time, not per sample. cascade() is a small convolution and is not hot-path. max_pole_magnitude() carries an Eigen dependency confined to the .cpp.

Definition in file Coefficients.hpp.