numcodecs_log/lib.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226
//! [![CI Status]][workflow] [![MSRV]][repo] [![Latest Version]][crates.io] [![Rust Doc Crate]][docs.rs] [![Rust Doc Main]][docs]
//!
//! [CI Status]: https://img.shields.io/github/actions/workflow/status/juntyr/numcodecs-rs/ci.yml?branch=main
//! [workflow]: https://github.com/juntyr/numcodecs-rs/actions/workflows/ci.yml?query=branch%3Amain
//!
//! [MSRV]: https://img.shields.io/badge/MSRV-1.76.0-blue
//! [repo]: https://github.com/juntyr/numcodecs-rs
//!
//! [Latest Version]: https://img.shields.io/crates/v/numcodecs-log
//! [crates.io]: https://crates.io/crates/numcodecs-log
//!
//! [Rust Doc Crate]: https://img.shields.io/docsrs/numcodecs-log
//! [docs.rs]: https://docs.rs/numcodecs-log/
//!
//! [Rust Doc Main]: https://img.shields.io/badge/docs-main-blue
//! [docs]: https://juntyr.github.io/numcodecs-rs/numcodecs_log
//!
//! `ln(x)` codec implementation for the [`numcodecs`] API.
use ndarray::{Array, ArrayBase, ArrayView, ArrayViewMut, Data, Dimension, Zip};
use num_traits::{Float, Signed};
use numcodecs::{
AnyArray, AnyArrayAssignError, AnyArrayDType, AnyArrayView, AnyArrayViewMut, AnyCowArray,
Codec, StaticCodec, StaticCodecConfig,
};
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use thiserror::Error;
#[derive(Clone, Serialize, Deserialize, JsonSchema)]
#[serde(deny_unknown_fields)]
/// Log codec which calculates `c = ln(x)` on encoding and `d = exp(c)` on
/// decoding.
///
/// The codec only supports finite positive floating point numbers.
pub struct LogCodec {
// empty
}
impl Codec for LogCodec {
type Error = LogCodecError;
fn encode(&self, data: AnyCowArray) -> Result<AnyArray, Self::Error> {
match data {
AnyCowArray::F32(data) => Ok(AnyArray::F32(ln(data)?)),
AnyCowArray::F64(data) => Ok(AnyArray::F64(ln(data)?)),
encoded => Err(LogCodecError::UnsupportedDtype(encoded.dtype())),
}
}
fn decode(&self, encoded: AnyCowArray) -> Result<AnyArray, Self::Error> {
match encoded {
AnyCowArray::F32(encoded) => Ok(AnyArray::F32(exp(encoded)?)),
AnyCowArray::F64(encoded) => Ok(AnyArray::F64(exp(encoded)?)),
encoded => Err(LogCodecError::UnsupportedDtype(encoded.dtype())),
}
}
fn decode_into(
&self,
encoded: AnyArrayView,
decoded: AnyArrayViewMut,
) -> Result<(), Self::Error> {
match (encoded, decoded) {
(AnyArrayView::F32(encoded), AnyArrayViewMut::F32(decoded)) => {
exp_into(encoded, decoded)
}
(AnyArrayView::F64(encoded), AnyArrayViewMut::F64(decoded)) => {
exp_into(encoded, decoded)
}
(encoded @ (AnyArrayView::F32(_) | AnyArrayView::F64(_)), decoded) => {
Err(LogCodecError::MismatchedDecodeIntoArray {
source: AnyArrayAssignError::DTypeMismatch {
src: encoded.dtype(),
dst: decoded.dtype(),
},
})
}
(encoded, _decoded) => Err(LogCodecError::UnsupportedDtype(encoded.dtype())),
}
}
}
impl StaticCodec for LogCodec {
const CODEC_ID: &'static str = "log";
type Config<'de> = Self;
fn from_config(config: Self::Config<'_>) -> Self {
config
}
fn get_config(&self) -> StaticCodecConfig<Self> {
StaticCodecConfig::from(self)
}
}
#[derive(Debug, Error)]
/// Errors that may occur when applying the [`LogCodec`].
pub enum LogCodecError {
/// [`LogCodec`] does not support the dtype
#[error("Log does not support the dtype {0}")]
UnsupportedDtype(AnyArrayDType),
/// [`LogCodec`] does not support non-positive (negative or zero) floating
/// point data
#[error("Log does not support non-positive (negative or zero) floating point data")]
NonPositiveData,
/// [`LogCodec`] does not support non-finite (infinite or NaN) floating
/// point data
#[error("Log does not support non-finite (infinite or NaN) floating point data")]
NonFiniteData,
/// [`LogCodec`] cannot decode into the provided array
#[error("Log cannot decode into the provided array")]
MismatchedDecodeIntoArray {
/// The source of the error
#[from]
source: AnyArrayAssignError,
},
}
/// Compute `ln(x)` over the elements of the input `data` array.
///
/// # Errors
///
/// Errors with
/// - [`LogCodecError::NonPositiveData`] if any data element is non-positive
/// (negative or zero)
/// - [`LogCodecError::NonFiniteData`] if any data element is non-finite
/// (infinite or NaN)
pub fn ln<T: Float + Signed, S: Data<Elem = T>, D: Dimension>(
data: ArrayBase<S, D>,
) -> Result<Array<T, D>, LogCodecError> {
if !Zip::from(&data).all(T::is_positive) {
return Err(LogCodecError::NonPositiveData);
}
if !Zip::from(&data).all(|x| x.is_finite()) {
return Err(LogCodecError::NonFiniteData);
}
let mut data = data.into_owned();
data.mapv_inplace(T::ln);
Ok(data)
}
/// Compute `exp(x)` over the elements of the input `data` array.
///
/// # Errors
///
/// Errors with
/// - [`LogCodecError::NonFiniteData`] if any data element is non-finite
/// (infinite or NaN)
pub fn exp<T: Float, S: Data<Elem = T>, D: Dimension>(
data: ArrayBase<S, D>,
) -> Result<Array<T, D>, LogCodecError> {
if !Zip::from(&data).all(|x| x.is_finite()) {
return Err(LogCodecError::NonFiniteData);
}
let mut data = data.into_owned();
data.mapv_inplace(T::exp);
Ok(data)
}
#[allow(clippy::needless_pass_by_value)]
/// Compute `exp(x)` over the elements of the input `data` array and write them
/// into the `out`put array.
///
/// # Errors
///
/// Errors with
/// - [`LogCodecError::NonFiniteData`] if any data element is non-finite
/// (infinite or NaN)
/// - [`LogCodecError::MismatchedDecodeIntoArray`] if the `data` array's shape
/// does not match the `out`put array's shape
pub fn exp_into<T: Float, D: Dimension>(
data: ArrayView<T, D>,
mut out: ArrayViewMut<T, D>,
) -> Result<(), LogCodecError> {
if data.shape() != out.shape() {
return Err(LogCodecError::MismatchedDecodeIntoArray {
source: AnyArrayAssignError::ShapeMismatch {
src: data.shape().to_vec(),
dst: out.shape().to_vec(),
},
});
}
if !Zip::from(&data).all(|x| x.is_finite()) {
return Err(LogCodecError::NonFiniteData);
}
// iteration must occur in synchronised (standard) order
for (d, o) in data.iter().zip(out.iter_mut()) {
*o = T::exp(*d);
}
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn roundtrip() -> Result<(), LogCodecError> {
let data = (1..1000).map(f64::from).collect::<Vec<_>>();
let data = Array::from_vec(data);
let encoded = ln(data.view())?;
for (r, e) in data.iter().zip(encoded.iter()) {
assert_eq!((*r).ln().to_bits(), (*e).to_bits());
}
let decoded = exp(encoded)?;
for (r, d) in data.iter().zip(decoded.iter()) {
assert!(((*r) - (*d)).abs() < 1e-12);
}
Ok(())
}
}