825d10c81a
We are currently not using LowPassFilter2p<double> and it just generates
a lot of warnings on PX4 while instantiating it due to implicitly
promoting float to double:
libraries/Filter/LowPassFilter2p.cpp: In instantiation of
'T DigitalBiquadFilter<T>::apply(const T&, const DigitalBiquadFilter<T>::biquad_params&) [with T = double]':
libraries/Filter/LowPassFilter2p.cpp:86:41: required from 'T LowPassFilter2p<T>::apply(const T&) [with T = double]'
libraries/Filter/LowPassFilter2p.cpp:98:16: required from here
libraries/Filter/LowPassFilter2p.cpp:20:82: warning: implicit conversion from 'float' to 'double' to match other
operand of binary expression [-Wdouble-promotion]
T delay_element_0 = sample - _delay_element_1 * params.a1 - _delay_element_2 * params.a2;
^
96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef LOWPASSFILTER2P_H
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#define LOWPASSFILTER2P_H
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#include <AP_Math/AP_Math.h>
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#include <math.h>
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#include <inttypes.h>
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/// @file LowPassFilter2p.h
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/// @brief A class to implement a second order low pass filter
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/// @authors: Leonard Hall <LeonardTHall@gmail.com>, template implmentation: Daniel Frenzel <dgdanielf@gmail.com>
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template <class T>
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class DigitalBiquadFilter {
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public:
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struct biquad_params {
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float cutoff_freq;
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float sample_freq;
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float a1;
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float a2;
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float b0;
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float b1;
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float b2;
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};
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DigitalBiquadFilter();
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T apply(const T &sample, const struct biquad_params ¶ms);
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void reset();
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static void compute_params(float sample_freq, float cutoff_freq, biquad_params &ret);
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private:
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T _delay_element_1;
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T _delay_element_2;
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};
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template <class T>
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class LowPassFilter2p {
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public:
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LowPassFilter2p();
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// constructor
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LowPassFilter2p(float sample_freq, float cutoff_freq);
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// change parameters
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void set_cutoff_frequency(float sample_freq, float cutoff_freq);
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// return the cutoff frequency
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float get_cutoff_freq(void) const;
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float get_sample_freq(void) const;
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T apply(const T &sample);
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protected:
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struct DigitalBiquadFilter<T>::biquad_params _params;
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private:
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DigitalBiquadFilter<T> _filter;
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};
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// Uncomment this, if you decide to remove the instantiations in the implementation file
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/*
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template <class T>
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LowPassFilter2p<T>::LowPassFilter2p() {
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memset(&_params, 0, sizeof(_params) );
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}
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// constructor
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template <class T>
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LowPassFilter2p<T>::LowPassFilter2p(float sample_freq, float cutoff_freq) {
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// set initial parameters
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set_cutoff_frequency(sample_freq, cutoff_freq);
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}
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*/
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typedef LowPassFilter2p<int> LowPassFilter2pInt;
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typedef LowPassFilter2p<long> LowPassFilter2pLong;
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typedef LowPassFilter2p<float> LowPassFilter2pFloat;
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typedef LowPassFilter2p<Vector2f> LowPassFilter2pVector2f;
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typedef LowPassFilter2p<Vector3f> LowPassFilter2pVector3f;
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#endif // LOWPASSFILTER2P_H
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