feat: adds accuracy, recall and precision metrics

src/metrics/accuracy.rs

@@ -0,0 +1,45 @@
+use serde::{Serialize, Deserialize};
+
+use crate::math::num::FloatExt;
+use crate::linalg::BaseVector;
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Accuracy{}
+
+impl Accuracy {
+    pub fn get_score<T: FloatExt, V: BaseVector<T>>(&self, y_true: &V, y_prod: &V) -> T {
+        if y_true.len() != y_prod.len() {
+            panic!("The vector sizes don't match: {} != {}", y_true.len(), y_prod.len());
+        }
+
+        let n = y_true.len();
+
+        let mut positive = 0;
+        for i in 0..n {
+            if y_true.get(i) == y_prod.get(i) {
+                positive += 1;
+            }
+        }
+
+        T::from_i64(positive).unwrap() / T::from_usize(n).unwrap()
+    }
+    
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;    
+
+    #[test]
+    fn accuracy() {
+        let y_pred: Vec<f64> = vec![0., 2., 1., 3.];
+        let y_true: Vec<f64> = vec![0., 1., 2., 3.];
+        
+        let score1: f64 = Accuracy{}.get_score(&y_pred, &y_true);
+        let score2: f64 = Accuracy{}.get_score(&y_true, &y_true);
+
+        assert!((score1 - 0.5).abs() < 1e-8);
+        assert!((score2 - 1.0).abs() < 1e-8);
+    }    
+
+}