162bed2aa2
* test: run tests also in wasm targets * fix: install rand with wasm-bindgen por wasm targets * fix: use actual usize size to access buffer. * fix: do not run functions that create files in wasm. * test: do not run in wasm test that panics. Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>
75 lines
2.3 KiB
Rust
75 lines
2.3 KiB
Rust
//! # F-measure
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//!
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//! Harmonic mean of the precision and recall.
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//!
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//! \\[f1 = (1 + \beta^2)\frac{precision \times recall}{\beta^2 \times precision + recall}\\]
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//!
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//! where \\(\beta \\) is a positive real factor, where \\(\beta \\) is chosen such that recall is considered \\(\beta \\) times as important as precision.
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//!
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//! Example:
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//!
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//! ```
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//! use smartcore::metrics::f1::F1;
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//! let y_pred: Vec<f64> = vec![0., 0., 1., 1., 1., 1.];
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//! let y_true: Vec<f64> = vec![0., 1., 1., 0., 1., 0.];
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//!
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//! let score: f64 = F1 {beta: 1.0}.get_score(&y_pred, &y_true);
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//! ```
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//!
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//! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
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//! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
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#[cfg(feature = "serde")]
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use serde::{Deserialize, Serialize};
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use crate::linalg::BaseVector;
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use crate::math::num::RealNumber;
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use crate::metrics::precision::Precision;
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use crate::metrics::recall::Recall;
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/// F-measure
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#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
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#[derive(Debug)]
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pub struct F1<T: RealNumber> {
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/// a positive real factor
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pub beta: T,
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}
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impl<T: RealNumber> F1<T> {
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/// Computes F1 score
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/// * `y_true` - cround truth (correct) labels.
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/// * `y_pred` - predicted labels, as returned by a classifier.
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pub fn get_score<V: BaseVector<T>>(&self, y_true: &V, y_pred: &V) -> T {
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if y_true.len() != y_pred.len() {
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panic!(
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"The vector sizes don't match: {} != {}",
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y_true.len(),
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y_pred.len()
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);
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}
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let beta2 = self.beta * self.beta;
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let p = Precision {}.get_score(y_true, y_pred);
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let r = Recall {}.get_score(y_true, y_pred);
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(T::one() + beta2) * (p * r) / (beta2 * p + r)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
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#[test]
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fn f1() {
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let y_pred: Vec<f64> = vec![0., 0., 1., 1., 1., 1.];
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let y_true: Vec<f64> = vec![0., 1., 1., 0., 1., 0.];
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let score1: f64 = F1 { beta: 1.0 }.get_score(&y_pred, &y_true);
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let score2: f64 = F1 { beta: 1.0 }.get_score(&y_true, &y_true);
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assert!((score1 - 0.57142857).abs() < 1e-8);
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assert!((score2 - 1.0).abs() < 1e-8);
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}
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}
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