diff --git a/src/metrics/precision.rs b/src/metrics/precision.rs
index dd09740c..84444b6b 100644
--- a/src/metrics/precision.rs
+++ b/src/metrics/precision.rs
@@ -4,7 +4,9 @@
//!
//! \\[precision = \frac{tp}{tp + fp}\\]
//!
-//! where tp (true positive) - correct result, fp (false positive) - unexpected result
+//! where tp (true positive) - correct result, fp (false positive) - unexpected result.
+//! For binary classification, this is precision for the positive class (assumed to be 1.0).
+//! For multiclass, this is macro-averaged precision (average of per-class precisions).
//!
//! Example:
//!
@@ -19,7 +21,8 @@
//!
//!
//!
-use std::collections::HashSet;
+
+use std::collections::{HashMap, HashSet};
use std::marker::PhantomData;
#[cfg(feature = "serde")]
@@ -61,33 +64,63 @@ impl Metrics for Precision {
);
}
- let mut classes = HashSet::new();
- for i in 0..y_true.shape() {
- classes.insert(y_true.get(i).to_f64_bits());
+ let n = y_true.shape();
+
+ let mut classes_set: HashSet = HashSet::new();
+ for i in 0..n {
+ classes_set.insert(y_true.get(i).to_f64_bits());
}
- let classes = classes.len();
-
- let mut tp = 0;
- let mut fp = 0;
- for i in 0..y_true.shape() {
- if y_pred.get(i) == y_true.get(i) {
- if classes == 2 {
- if *y_true.get(i) == T::one() {
+ let classes: usize = classes_set.len();
+
+ if classes == 2 {
+ // Binary case: precision for positive class (assumed T::one())
+ let positive = T::one();
+ let mut tp: usize = 0;
+ let mut fp_count: usize = 0;
+ for i in 0..n {
+ let t = *y_true.get(i);
+ let p = *y_pred.get(i);
+ if p == t {
+ if t == positive {
tp += 1;
}
- } else {
- tp += 1;
+ } else if t != positive {
+ fp_count += 1;
}
- } else if classes == 2 {
- if *y_true.get(i) == T::one() {
- fp += 1;
+ }
+ if tp + fp_count == 0 {
+ 0.0
+ } else {
+ tp as f64 / (tp + fp_count) as f64
+ }
+ } else {
+ // Multiclass case: macro-averaged precision
+ let mut predicted: HashMap = HashMap::new();
+ let mut tp_map: HashMap = HashMap::new();
+ for i in 0..n {
+ let p_bits = y_pred.get(i).to_f64_bits();
+ *predicted.entry(p_bits).or_insert(0) += 1;
+ if *y_true.get(i) == *y_pred.get(i) {
+ *tp_map.entry(p_bits).or_insert(0) += 1;
}
+ }
+ let mut precision_sum = 0.0;
+ for &bits in &classes_set {
+ let pred_count = *predicted.get(&bits).unwrap_or(&0);
+ let tp = *tp_map.get(&bits).unwrap_or(&0);
+ let prec = if pred_count > 0 {
+ tp as f64 / pred_count as f64
+ } else {
+ 0.0
+ };
+ precision_sum += prec;
+ }
+ if classes == 0 {
+ 0.0
} else {
- fp += 1;
+ precision_sum / classes as f64
}
}
-
- tp as f64 / (tp as f64 + fp as f64)
}
}
@@ -114,7 +147,7 @@ mod tests {
let y_pred: Vec = vec![0., 0., 1., 1., 1., 1.];
let score3: f64 = Precision::new().get_score(&y_true, &y_pred);
- assert!((score3 - 0.6666666666).abs() < 1e-8);
+ assert!((score3 - 0.5).abs() < 1e-8);
}
#[cfg_attr(
@@ -132,4 +165,36 @@ mod tests {
assert!((score1 - 0.333333333).abs() < 1e-8);
assert!((score2 - 1.0).abs() < 1e-8);
}
+
+ #[cfg_attr(
+ all(target_arch = "wasm32", not(target_os = "wasi")),
+ wasm_bindgen_test::wasm_bindgen_test
+ )]
+ #[test]
+ fn precision_multiclass_imbalanced() {
+ let y_true: Vec = vec![0., 0., 1., 2., 2., 2.];
+ let y_pred: Vec = vec![0., 1., 1., 2., 0., 2.];
+
+ let score: f64 = Precision::new().get_score(&y_true, &y_pred);
+ let expected = (0.5 + 0.5 + 1.0) / 3.0;
+ assert!((score - expected).abs() < 1e-8);
+ }
+
+ #[cfg_attr(
+ all(target_arch = "wasm32", not(target_os = "wasi")),
+ wasm_bindgen_test::wasm_bindgen_test
+ )]
+ #[test]
+ fn precision_multiclass_unpredicted_class() {
+ let y_true: Vec = vec![0., 0., 1., 2., 2., 2., 3.];
+ let y_pred: Vec = vec![0., 1., 1., 2., 0., 2., 0.];
+
+ let score: f64 = Precision::new().get_score(&y_true, &y_pred);
+ // Class 0: pred=3, tp=1 -> 1/3 ≈0.333
+ // Class 1: pred=2, tp=1 -> 0.5
+ // Class 2: pred=2, tp=2 -> 1.0
+ // Class 3: pred=0, tp=0 -> 0.0
+ let expected = (1.0 / 3.0 + 0.5 + 1.0 + 0.0) / 4.0;
+ assert!((score - expected).abs() < 1e-8);
+ }
}
diff --git a/src/metrics/recall.rs b/src/metrics/recall.rs
index ab76d972..e7418511 100644
--- a/src/metrics/recall.rs
+++ b/src/metrics/recall.rs
@@ -4,7 +4,9 @@
//!
//! \\[recall = \frac{tp}{tp + fn}\\]
//!
-//! where tp (true positive) - correct result, fn (false negative) - missing result
+//! where tp (true positive) - correct result, fn (false negative) - missing result.
+//! For binary classification, this is recall for the positive class (assumed to be 1.0).
+//! For multiclass, this is macro-averaged recall (average of per-class recalls).
//!
//! Example:
//!
@@ -20,8 +22,7 @@
//!
//!
-use std::collections::HashSet;
-use std::convert::TryInto;
+use std::collections::{HashMap, HashSet};
use std::marker::PhantomData;
#[cfg(feature = "serde")]
@@ -52,7 +53,7 @@ impl Metrics for Recall {
}
}
/// Calculated recall score
- /// * `y_true` - cround truth (correct) labels.
+ /// * `y_true` - ground truth (correct) labels.
/// * `y_pred` - predicted labels, as returned by a classifier.
fn get_score(&self, y_true: &dyn ArrayView1, y_pred: &dyn ArrayView1) -> f64 {
if y_true.shape() != y_pred.shape() {
@@ -63,32 +64,57 @@ impl Metrics for Recall {
);
}
- let mut classes = HashSet::new();
- for i in 0..y_true.shape() {
- classes.insert(y_true.get(i).to_f64_bits());
+ let n = y_true.shape();
+
+ let mut classes_set = HashSet::new();
+ for i in 0..n {
+ classes_set.insert(y_true.get(i).to_f64_bits());
}
- let classes: i64 = classes.len().try_into().unwrap();
-
- let mut tp = 0;
- let mut fne = 0;
- for i in 0..y_true.shape() {
- if y_pred.get(i) == y_true.get(i) {
- if classes == 2 {
- if *y_true.get(i) == T::one() {
+ let classes: usize = classes_set.len();
+
+ if classes == 2 {
+ // Binary case: recall for positive class (assumed T::one())
+ let positive = T::one();
+ let mut tp: usize = 0;
+ let mut fn_count: usize = 0;
+ for i in 0..n {
+ let t = *y_true.get(i);
+ let p = *y_pred.get(i);
+ if p == t {
+ if t == positive {
tp += 1;
}
- } else {
- tp += 1;
+ } else if t == positive {
+ fn_count += 1;
}
- } else if classes == 2 {
- if *y_true.get(i) != T::one() {
- fne += 1;
+ }
+ if tp + fn_count == 0 {
+ 0.0
+ } else {
+ tp as f64 / (tp + fn_count) as f64
+ }
+ } else {
+ // Multiclass case: macro-averaged recall
+ let mut support: HashMap = HashMap::new();
+ let mut tp_map: HashMap = HashMap::new();
+ for i in 0..n {
+ let t_bits = y_true.get(i).to_f64_bits();
+ *support.entry(t_bits).or_insert(0) += 1;
+ if *y_true.get(i) == *y_pred.get(i) {
+ *tp_map.entry(t_bits).or_insert(0) += 1;
}
+ }
+ let mut recall_sum = 0.0;
+ for (&bits, &sup) in &support {
+ let tp = *tp_map.get(&bits).unwrap_or(&0);
+ recall_sum += tp as f64 / sup as f64;
+ }
+ if support.is_empty() {
+ 0.0
} else {
- fne += 1;
+ recall_sum / support.len() as f64
}
}
- tp as f64 / (tp as f64 + fne as f64)
}
}
@@ -115,7 +141,7 @@ mod tests {
let y_pred: Vec = vec![0., 0., 1., 1., 1., 1.];
let score3: f64 = Recall::new().get_score(&y_true, &y_pred);
- assert!((score3 - 0.5).abs() < 1e-8);
+ assert!((score3 - (2.0 / 3.0)).abs() < 1e-8);
}
#[cfg_attr(
@@ -133,4 +159,18 @@ mod tests {
assert!((score1 - 0.333333333).abs() < 1e-8);
assert!((score2 - 1.0).abs() < 1e-8);
}
+
+ #[cfg_attr(
+ all(target_arch = "wasm32", not(target_os = "wasi")),
+ wasm_bindgen_test::wasm_bindgen_test
+ )]
+ #[test]
+ fn recall_multiclass_imbalanced() {
+ let y_true: Vec = vec![0., 0., 1., 2., 2., 2.];
+ let y_pred: Vec = vec![0., 1., 1., 2., 0., 2.];
+
+ let score: f64 = Recall::new().get_score(&y_true, &y_pred);
+ let expected = (0.5 + 1.0 + (2.0 / 3.0)) / 3.0;
+ assert!((score - expected).abs() < 1e-8);
+ }
}