Add unit tests for activation functions: sigmoid, relu, dsigmoid, and drelu

src/compute/activations.rs

@@ -16,3 +16,45 @@ pub fn relu(x: &Matrix<f64>) -> Matrix<f64> {
 pub fn drelu(x: &Matrix<f64>) -> Matrix<f64> {
     x.map(|v| if v > 0.0 { 1.0 } else { 0.0 })
 }
+
+
+mod tests {
+    use super::*;
+    
+    // Helper function to round all elements in a matrix to n decimal places
+    fn _round_matrix(mat: &Matrix<f64>, decimals: u32) -> Matrix<f64> {
+        let factor = 10f64.powi(decimals as i32);
+        let rounded: Vec<f64> = mat.to_vec().iter().map(|v| (v * factor).round() / factor).collect();
+        Matrix::from_vec(rounded, mat.rows(), mat.cols())
+    }
+
+    #[test]
+    fn test_sigmoid() {
+        let x = Matrix::from_vec(vec![-1.0, 0.0, 1.0], 3, 1);
+        let expected = Matrix::from_vec(vec![0.26894142, 0.5, 0.73105858], 3, 1);
+        let result = sigmoid(&x);
+        assert_eq!(_round_matrix(&result, 6), _round_matrix(&expected, 6));
+    }
+
+    #[test]
+    fn test_relu() {
+        let x = Matrix::from_vec(vec![-1.0, 0.0, 1.0], 3, 1);
+        let expected = Matrix::from_vec(vec![0.0, 0.0, 1.0], 3, 1);
+        assert_eq!(relu(&x), expected);
+    }
+
+    #[test]
+    fn test_dsigmoid() {
+        let y = Matrix::from_vec(vec![0.26894142, 0.5, 0.73105858], 3, 1);
+        let expected = Matrix::from_vec(vec![0.19661193, 0.25, 0.19661193], 3, 1);
+        let result = dsigmoid(&y);
+        assert_eq!(_round_matrix(&result, 6), _round_matrix(&expected, 6));
+    }
+    
+    #[test]
+    fn test_drelu() {
+        let x = Matrix::from_vec(vec![-1.0, 0.0, 1.0], 3, 1);
+        let expected = Matrix::from_vec(vec![0.0, 0.0, 1.0], 3, 1);
+        assert_eq!(drelu(&x), expected);    
+    }
+}