275: use num crate r=jordens a=jordens

* Use `num` crate
* Clean up lowpass gain handling

* [x] test on hardware

Co-authored-by: Robert Jördens <rj@quartiq.de>
This commit is contained in:
bors[bot] 2021-02-19 08:51:04 +00:00 committed by GitHub
commit 83e770509e
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GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 257 additions and 196 deletions

36
Cargo.lock generated
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@ -356,6 +356,7 @@ dependencies = [
"generic-array 0.14.4",
"libm",
"ndarray",
"num",
"rand",
"serde",
]
@ -623,6 +624,19 @@ dependencies = [
"rawpointer",
]
[[package]]
name = "num"
version = "0.3.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8b7a8e9be5e039e2ff869df49155f1c06bd01ade2117ec783e56ab0932b67a8f"
dependencies = [
"num-complex",
"num-integer",
"num-iter",
"num-rational",
"num-traits",
]
[[package]]
name = "num-complex"
version = "0.3.1"
@ -642,6 +656,28 @@ dependencies = [
"num-traits",
]
[[package]]
name = "num-iter"
version = "0.1.42"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b2021c8337a54d21aca0d59a92577a029af9431cb59b909b03252b9c164fad59"
dependencies = [
"autocfg",
"num-integer",
"num-traits",
]
[[package]]
name = "num-rational"
version = "0.3.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "12ac428b1cb17fce6f731001d307d351ec70a6d202fc2e60f7d4c5e42d8f4f07"
dependencies = [
"autocfg",
"num-integer",
"num-traits",
]
[[package]]
name = "num-traits"
version = "0.2.14"

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@ -8,6 +8,7 @@ edition = "2018"
libm = "0.2.1"
serde = { version = "1.0", features = ["derive"], default-features = false }
generic-array = "0.14"
num = { version = "0.3.1", default-features = false }
[dev-dependencies]
criterion = "0.3"

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@ -1,8 +1,6 @@
use core::f32::consts::PI;
use criterion::{black_box, criterion_group, criterion_main, Criterion};
use dsp::{atan2, cossin};
use dsp::{iir, iir_int};
use dsp::{pll::PLL, rpll::RPLL};
use dsp::{atan2, cossin, iir, iir_int, PLL, RPLL};
fn atan2_bench(c: &mut Criterion) {
let xi = (10 << 16) as i32;

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@ -1,33 +1,29 @@
use core::ops::Mul;
pub use num::Complex;
use super::{atan2, cossin};
#[derive(Copy, Clone, Default, PartialEq, Debug)]
pub struct Complex<T>(pub T, pub T);
impl<T: Copy> Complex<T> {
pub fn map<F>(&self, func: F) -> Self
where
F: Fn(T) -> T,
{
Complex(func(self.0), func(self.1))
}
/// Complex extension trait offering DSP (fast, good accuracy) functionality.
pub trait ComplexExt<T, U> {
fn from_angle(angle: T) -> Self;
fn abs_sqr(&self) -> U;
fn log2(&self) -> T;
fn arg(&self) -> T;
}
impl Complex<i32> {
impl ComplexExt<i32, u32> for Complex<i32> {
/// Return a Complex on the unit circle given an angle.
///
/// Example:
///
/// ```
/// use dsp::Complex;
/// use dsp::{Complex, ComplexExt};
/// Complex::<i32>::from_angle(0);
/// Complex::<i32>::from_angle(1 << 30); // pi/2
/// Complex::<i32>::from_angle(-1 << 30); // -pi/2
/// ```
pub fn from_angle(angle: i32) -> Self {
fn from_angle(angle: i32) -> Self {
let (c, s) = cossin(angle);
Self(c, s)
Self { re: c, im: s }
}
/// Return the absolute square (the squared magnitude).
@ -39,13 +35,13 @@ impl Complex<i32> {
/// Example:
///
/// ```
/// use dsp::Complex;
/// assert_eq!(Complex(i32::MIN, 0).abs_sqr(), 1 << 31);
/// assert_eq!(Complex(i32::MAX, i32::MAX).abs_sqr(), u32::MAX - 3);
/// use dsp::{Complex, ComplexExt};
/// assert_eq!(Complex::new(i32::MIN, 0).abs_sqr(), 1 << 31);
/// assert_eq!(Complex::new(i32::MAX, i32::MAX).abs_sqr(), u32::MAX - 3);
/// ```
pub fn abs_sqr(&self) -> u32 {
(((self.0 as i64) * (self.0 as i64)
+ (self.1 as i64) * (self.1 as i64))
fn abs_sqr(&self) -> u32 {
(((self.re as i64) * (self.re as i64)
+ (self.im as i64) * (self.im as i64))
>> 31) as u32
}
@ -59,15 +55,15 @@ impl Complex<i32> {
/// Example:
///
/// ```
/// use dsp::Complex;
/// assert_eq!(Complex(i32::MAX, i32::MAX).log2(), -1);
/// assert_eq!(Complex(i32::MAX, 0).log2(), -2);
/// assert_eq!(Complex(1, 0).log2(), -63);
/// assert_eq!(Complex(0, 0).log2(), -64);
/// use dsp::{Complex, ComplexExt};
/// assert_eq!(Complex::new(i32::MAX, i32::MAX).log2(), -1);
/// assert_eq!(Complex::new(i32::MAX, 0).log2(), -2);
/// assert_eq!(Complex::new(1, 0).log2(), -63);
/// assert_eq!(Complex::new(0, 0).log2(), -64);
/// ```
pub fn log2(&self) -> i32 {
let a = (self.0 as i64) * (self.0 as i64)
+ (self.1 as i64) * (self.1 as i64);
fn log2(&self) -> i32 {
let a = (self.re as i64) * (self.re as i64)
+ (self.im as i64) * (self.im as i64);
-(a.leading_zeros() as i32)
}
@ -78,52 +74,51 @@ impl Complex<i32> {
/// Example:
///
/// ```
/// use dsp::Complex;
/// assert_eq!(Complex(1, 0).arg(), 0);
/// assert_eq!(Complex(-i32::MAX, 1).arg(), i32::MAX);
/// assert_eq!(Complex(-i32::MAX, -1).arg(), -i32::MAX);
/// assert_eq!(Complex(0, -1).arg(), -i32::MAX >> 1);
/// assert_eq!(Complex(0, 1).arg(), (i32::MAX >> 1) + 1);
/// assert_eq!(Complex(1, 1).arg(), (i32::MAX >> 2) + 1);
/// use dsp::{Complex, ComplexExt};
/// assert_eq!(Complex::new(1, 0).arg(), 0);
/// assert_eq!(Complex::new(-i32::MAX, 1).arg(), i32::MAX);
/// assert_eq!(Complex::new(-i32::MAX, -1).arg(), -i32::MAX);
/// assert_eq!(Complex::new(0, -1).arg(), -i32::MAX >> 1);
/// assert_eq!(Complex::new(0, 1).arg(), (i32::MAX >> 1) + 1);
/// assert_eq!(Complex::new(1, 1).arg(), (i32::MAX >> 2) + 1);
/// ```
pub fn arg(&self) -> i32 {
atan2(self.1, self.0)
fn arg(&self) -> i32 {
atan2(self.im, self.re)
}
}
impl Mul for Complex<i32> {
type Output = Self;
/// Full scale fixed point multiplication.
pub trait MulScaled<T> {
fn mul_scaled(self, other: T) -> Self;
}
fn mul(self, other: Self) -> Self {
let a = self.0 as i64;
let b = self.1 as i64;
let c = other.0 as i64;
let d = other.1 as i64;
Complex(
((a * c - b * d + (1 << 31)) >> 32) as i32,
((b * c + a * d + (1 << 31)) >> 32) as i32,
)
impl MulScaled<Complex<i32>> for Complex<i32> {
fn mul_scaled(self, other: Self) -> Self {
let a = self.re as i64;
let b = self.im as i64;
let c = other.re as i64;
let d = other.im as i64;
Complex {
re: ((a * c - b * d + (1 << 30)) >> 31) as i32,
im: ((b * c + a * d + (1 << 30)) >> 31) as i32,
}
}
}
impl Mul<i32> for Complex<i32> {
type Output = Self;
fn mul(self, other: i32) -> Self {
Complex(
((other as i64 * self.0 as i64 + (1 << 31)) >> 32) as i32,
((other as i64 * self.1 as i64 + (1 << 31)) >> 32) as i32,
)
impl MulScaled<i32> for Complex<i32> {
fn mul_scaled(self, other: i32) -> Self {
Complex {
re: ((other as i64 * self.re as i64 + (1 << 30)) >> 31) as i32,
im: ((other as i64 * self.im as i64 + (1 << 30)) >> 31) as i32,
}
}
}
impl Mul<i16> for Complex<i32> {
type Output = Self;
fn mul(self, other: i16) -> Self {
Complex(
(other as i32 * (self.0 >> 16) + (1 << 15)) >> 16,
(other as i32 * (self.1 >> 16) + (1 << 15)) >> 16,
)
impl MulScaled<i16> for Complex<i32> {
fn mul_scaled(self, other: i16) -> Self {
Complex {
re: (other as i32 * (self.re >> 16) + (1 << 14)) >> 15,
im: (other as i32 * (self.im >> 16) + (1 << 14)) >> 15,
}
}
}

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@ -74,7 +74,6 @@ pub fn cossin(phase: i32) -> (i32, i32) {
#[cfg(test)]
mod tests {
use super::*;
use crate::Complex;
use core::f64::consts::PI;
#[test]
@ -82,11 +81,11 @@ mod tests {
// Constant amplitude error due to LUT data range.
const AMPLITUDE: f64 = ((1i64 << 31) - (1i64 << 15)) as _;
const MAX_PHASE: f64 = (1i64 << 32) as _;
let mut rms_err = Complex(0f64, 0f64);
let mut sum_err = Complex(0f64, 0f64);
let mut max_err = Complex(0f64, 0f64);
let mut sum = Complex(0f64, 0f64);
let mut demod = Complex(0f64, 0f64);
let mut rms_err = (0f64, 0f64);
let mut sum_err = (0f64, 0f64);
let mut max_err = (0f64, 0f64);
let mut sum = (0f64, 0f64);
let mut demod = (0f64, 0f64);
// use std::{fs::File, io::{BufWriter, prelude::*}, path::Path};
// let mut file = BufWriter::new(File::create(Path::new("data.bin")).unwrap());

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@ -1,101 +1,28 @@
#![cfg_attr(not(test), no_std)]
#![cfg_attr(feature = "nightly", feature(asm, core_intrinsics))]
use core::ops::{Add, Mul, Neg};
fn abs<T>(x: T) -> T
where
T: PartialOrd + Default + Neg<Output = T>,
{
if x >= T::default() {
x
} else {
-x
}
}
// These are implemented here because core::f32 doesn't have them (yet).
// They are naive and don't handle inf/nan.
// `compiler-intrinsics`/llvm should have better (robust, universal, and
// faster) implementations.
fn copysign<T>(x: T, y: T) -> T
where
T: PartialOrd + Default + Neg<Output = T>,
{
if (x >= T::default() && y >= T::default())
|| (x <= T::default() && y <= T::default())
{
x
} else {
-x
}
}
#[cfg(not(feature = "nightly"))]
fn max<T>(x: T, y: T) -> T
where
T: PartialOrd,
{
if x > y {
x
} else {
y
}
}
#[cfg(not(feature = "nightly"))]
fn min<T>(x: T, y: T) -> T
where
T: PartialOrd,
{
if x < y {
x
} else {
y
}
}
#[cfg(feature = "nightly")]
fn max(x: f32, y: f32) -> f32 {
core::intrinsics::maxnumf32(x, y)
}
#[cfg(feature = "nightly")]
fn min(x: f32, y: f32) -> f32 {
core::intrinsics::minnumf32(x, y)
}
// Multiply-accumulate vectors `x` and `a`.
//
// A.k.a. dot product.
// Rust/LLVM optimize this nicely.
fn macc<T>(y0: T, x: &[T], a: &[T]) -> T
where
T: Add<Output = T> + Mul<Output = T> + Copy,
{
x.iter()
.zip(a)
.map(|(x, a)| *x * *a)
.fold(y0, |y, xa| y + xa)
}
pub mod accu;
mod tools;
pub use tools::*;
mod atan2;
pub use atan2::*;
mod accu;
pub use accu::*;
mod complex;
pub use complex::*;
mod cossin;
pub use cossin::*;
pub mod iir;
pub mod iir_int;
pub mod lockin;
pub mod lowpass;
pub mod pll;
pub mod rpll;
pub mod unwrap;
pub use accu::Accu;
pub use atan2::atan2;
pub use complex::Complex;
pub use cossin::cossin;
mod lockin;
pub use lockin::*;
mod lowpass;
pub use lowpass::*;
mod pll;
pub use pll::*;
mod rpll;
pub use rpll::*;
mod unwrap;
pub use unwrap::*;
#[cfg(test)]
pub mod testing;

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@ -1,4 +1,4 @@
use super::{lowpass::Lowpass, Complex};
use super::{Complex, ComplexExt, Lowpass, MulScaled};
use generic_array::typenum::U2;
#[derive(Clone, Default)]
@ -8,19 +8,15 @@ pub struct Lockin {
impl Lockin {
/// Update the lockin with a sample taken at a given phase.
/// The lowpass has a gain of `1 << k`.
pub fn update(&mut self, sample: i16, phase: i32, k: u8) -> Complex<i32> {
// Get the LO signal for demodulation.
let lo = Complex::from_angle(phase);
// Mix with the LO signal
let mix = lo * sample;
pub fn update(&mut self, sample: i32, phase: i32, k: u8) -> Complex<i32> {
// Get the LO signal for demodulation and mix the sample;
let mix = Complex::from_angle(phase).mul_scaled(sample);
// Filter with the IIR lowpass,
// return IQ (in-phase and quadrature) data.
Complex(
self.state[0].update(mix.0, k),
self.state[1].update(mix.1, k),
)
Complex {
re: self.state[0].update(mix.re, k),
im: self.state[1].update(mix.im, k),
}
}
}

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@ -14,19 +14,20 @@ impl<N: ArrayLength<i32>> Lowpass<N> {
/// Update the filter with a new sample.
///
/// # Args
/// * `x`: Input data, needs `k` bits headroom.
/// * `k`: Log2 time constant, 0..31.
/// * `x`: Input data. Needs 1 bit headroom but will saturate cleanly beyond that.
/// * `k`: Log2 time constant, 1..=31.
///
/// # Return
/// Filtered output y, with gain of `1 << k`.
/// Filtered output y.
pub fn update(&mut self, x: i32, k: u8) -> i32 {
debug_assert!(k & 31 == k);
debug_assert!((k - 1) & 31 == k - 1);
// This is an unrolled and optimized first-order IIR loop
// that works for all possible time constants.
// Note DF-II and the zeros at Nyquist.
let mut x = x << k;
// Note T-DF-I and the zeros at Nyquist.
let mut x = x;
for y in self.y.iter_mut() {
let dy = (x - *y + (1 << (k - 1))) >> k;
let dy = x.saturating_sub(*y).saturating_add(1 << (k - 1)) >> k;
*y += dy;
x = *y - (dy >> 1);
}

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@ -31,7 +31,7 @@ pub fn complex_isclose(
rtol: f32,
atol: f32,
) -> bool {
isclosef(a.0, b.0, rtol, atol) && isclosef(a.1, b.1, rtol, atol)
isclosef(a.re, b.re, rtol, atol) && isclosef(a.im, b.im, rtol, atol)
}
pub fn complex_allclose(

95
dsp/src/tools.rs Normal file
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@ -0,0 +1,95 @@
use core::ops::{Add, Mul, Neg};
pub fn abs<T>(x: T) -> T
where
T: PartialOrd + Default + Neg<Output = T>,
{
if x >= T::default() {
x
} else {
-x
}
}
// These are implemented here because core::f32 doesn't have them (yet).
// They are naive and don't handle inf/nan.
// `compiler-intrinsics`/llvm should have better (robust, universal, and
// faster) implementations.
pub fn copysign<T>(x: T, y: T) -> T
where
T: PartialOrd + Default + Neg<Output = T>,
{
if (x >= T::default() && y >= T::default())
|| (x <= T::default() && y <= T::default())
{
x
} else {
-x
}
}
#[cfg(not(feature = "nightly"))]
pub fn max<T>(x: T, y: T) -> T
where
T: PartialOrd,
{
if x > y {
x
} else {
y
}
}
#[cfg(not(feature = "nightly"))]
pub fn min<T>(x: T, y: T) -> T
where
T: PartialOrd,
{
if x < y {
x
} else {
y
}
}
#[cfg(feature = "nightly")]
pub fn max(x: f32, y: f32) -> f32 {
core::intrinsics::maxnumf32(x, y)
}
#[cfg(feature = "nightly")]
pub fn min(x: f32, y: f32) -> f32 {
core::intrinsics::minnumf32(x, y)
}
// Multiply-accumulate vectors `x` and `a`.
//
// A.k.a. dot product.
// Rust/LLVM optimize this nicely.
pub fn macc<T>(y0: T, x: &[T], a: &[T]) -> T
where
T: Add<Output = T> + Mul<Output = T> + Copy,
{
x.iter()
.zip(a)
.map(|(x, a)| *x * *a)
.fold(y0, |y, xa| y + xa)
}
/// Combine high and low i32 into a single downscaled i32, saturating the type.
pub fn saturating_scale(lo: i32, hi: i32, shift: u32) -> i32 {
debug_assert!(shift & 31 == shift);
let shift_hi = 31 - shift;
debug_assert!(shift_hi & 31 == shift_hi);
let over = hi >> shift;
if over < -1 {
i32::MIN
} else if over > 0 {
i32::MAX
} else {
(lo >> shift) + (hi << shift_hi)
}
}

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@ -6,7 +6,7 @@ use stm32h7xx_hal as hal;
use stabilizer::{hardware, hardware::design_parameters};
use dsp::{lockin::Lockin, rpll::RPLL, Accu};
use dsp::{Accu, Complex, ComplexExt, Lockin, RPLL};
use hardware::{
Adc0Input, Adc1Input, Dac0Output, Dac1Output, InputStamper, AFE0, AFE1,
};
@ -112,22 +112,33 @@ const APP: () = {
let sample_phase =
phase_offset.wrapping_add(pll_phase.wrapping_mul(harmonic));
let output = adc_samples[0]
let output: Complex<i32> = adc_samples[0]
.iter()
// Zip in the LO phase.
.zip(Accu::new(sample_phase, sample_frequency))
// Convert to signed, MSB align the ADC sample.
// Convert to signed, MSB align the ADC sample, update the Lockin (demodulate, filter)
.map(|(&sample, phase)| {
lockin.update(sample as i16, phase, time_constant)
let s = (sample as i16 as i32) << 16;
lockin.update(s, phase, time_constant)
})
// Decimate
.last()
.unwrap();
.unwrap()
* 2; // Full scale assuming the 2f component is gone.
let conf = "frequency_discriminator";
#[allow(dead_code)]
enum Conf {
PowerPhase,
FrequencyDiscriminator,
Quadrature,
}
let conf = Conf::FrequencyDiscriminator; // TODO: expose
let output = match conf {
// Convert from IQ to power and phase.
"power_phase" => [(output.log2() << 24) as _, output.arg()],
"frequency_discriminator" => [pll_frequency as _, output.arg()],
_ => [output.0, output.1],
Conf::PowerPhase => [(output.log2() << 24) as _, output.arg()],
Conf::FrequencyDiscriminator => [pll_frequency as _, output.arg()],
Conf::Quadrature => [output.re, output.im],
};
// Convert to DAC data.

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@ -2,7 +2,7 @@
#![no_std]
#![no_main]
use dsp::{lockin::Lockin, Accu};
use dsp::{Accu, Complex, ComplexExt, Lockin};
use hardware::{Adc1Input, Dac0Output, Dac1Output, AFE0, AFE1};
use stabilizer::{hardware, hardware::design_parameters};
@ -95,17 +95,19 @@ const APP: () = {
let sample_phase = phase_offset
.wrapping_add((pll_phase as i32).wrapping_mul(harmonic));
let output = adc_samples
let output: Complex<i32> = adc_samples
.iter()
// Zip in the LO phase.
.zip(Accu::new(sample_phase, sample_frequency))
// Convert to signed, MSB align the ADC sample, update the Lockin (demodulate, filter)
.map(|(&sample, phase)| {
lockin.update(sample as i16, phase, time_constant)
let s = (sample as i16 as i32) << 16;
lockin.update(s, phase, time_constant)
})
// Decimate
.last()
.unwrap();
.unwrap()
* 2; // Full scale assuming the 2f component is gone.
for value in dac_samples[1].iter_mut() {
*value = (output.arg() >> 16) as u16 ^ 0x8000;