feat: create subtraction of matrices

src/matrix.rs

@@ -10,8 +10,8 @@
 //! println!("m1 + m2 =\n{}", m_add);
 //! ```
 //! TODO:: Create matrix multiplication method
-use core::ops::AddAssign;
 use crate::error::{MatrixSetValueError, ParseMatrixError};
+use core::ops::AddAssign;
 use std::{
     fmt::Display,
     ops::{Add, Mul, Sub},
@@ -146,6 +146,9 @@ impl Matrix {
             data: d,
         }
     }
+    pub fn same_dimensions(&self, other: &Matrix) -> bool {
+        self.nrows == other.nrows && self.ncols == other.ncols
+    }
     /// Query one element at selected position.
     ///
     /// Returns `None` if index is out of bounds.
@@ -172,6 +175,21 @@ impl Matrix {
     pub fn is_square(&self) -> bool {
         self.nrows == self.ncols
     }
+    pub fn permute_op(&self, op: fn(f32) -> f32) -> Matrix {
+        let mut i = 0;
+        let mut j = 0;
+        let mut rs: Vec<Vec<f32>> = Vec::new();
+        while i < self.nrows {
+            let mut r: Vec<f32> = Vec::new();
+            while j < self.ncols {
+                r.push(op(self.get(i, j).unwrap()));
+                j += 1;
+            }
+            rs.push(r);
+            i += 1;
+        }
+        Matrix::new(rs)
+    }
     fn splice(&self, at_index: usize, at_row: usize) -> Matrix {
         let mut data: Vec<Vec<f32>> = Vec::new();
         for i in 0..self.data.len() {
@@ -235,7 +253,7 @@ impl Display for Matrix {
 impl<'a, 'b> Add<&'b Matrix> for &'a Matrix {
     type Output = Matrix;
     fn add(self, rhs: &'b Matrix) -> Self::Output {
-        if (self.nrows != rhs.nrows) || (self.ncols != rhs.ncols) {
+        if !self.same_dimensions(rhs) {
             panic!("Cannot add two matrices with different dimensions");
         }
         let mut x = Matrix {
@@ -254,7 +272,11 @@ impl<'a, 'b> Add<&'b Matrix> for &'a Matrix {
 impl<'a, 'b> Sub<&'b Matrix> for &'a Matrix {
     type Output = Matrix;
     fn sub(self, rhs: &'b Matrix) -> Self::Output {
-        todo!()
+        if !self.same_dimensions(rhs) {
+            panic!("Cannot subtract two matrices with different dimensions");
+        }
+        let neg = rhs.permute_op(|x| -x);
+        self - &neg
     }
 }
 impl<'a> Mul<&'a Matrix> for f32 {

src/tests/matrix_test_ops.rs

@@ -13,14 +13,35 @@ struct TestCase {
     test_type: TestCaseType,
     test_data: Vec<Matrix>,
 }
+fn build_mul_test_cases() -> Vec<TestCase> {
+    let mut v = vec![];
+    let from_strs = vec![
+        "1,2\n1,2",
+        "1,3\n2,4",
+        "5,11\n5,11",
+        "1,2\n3,4",
+        "1\n2",
+        "5\n11",
+    ];
+    let mut i = 0;
+    while i < from_strs.len() {
+        let m1 = Matrix::from_str(from_strs[i]).unwrap();
+        let m2 = Matrix::from_str(from_strs[i + 1]).unwrap();
+        let re = Matrix::from_str(from_strs[i + 2]).unwrap();
+        v.push(TestCase {
+            test_type: TestCaseType::Mul,
+            test_data: vec![m1, m2, re],
+        });
+        i += 3;
+    }
+    v
+}
 fn build_add_test_cases() -> Vec<TestCase> {
     let mut v = vec![];
     let from_strs = vec![
         "1,2,3\n4,5,6\n7,8,9",
         "1,1,1\n1,1,1\n1,1,1",
         "2,3,4\n5,6,7\n8,9,10",
-
-
         "1,1,1\n1,1,1\n1,1,1",
         "0,0,0\n0,0,0\n0,0,0",
         "1,1,1\n1,1,1\n1,1,1",
@@ -28,8 +49,8 @@ fn build_add_test_cases() -> Vec<TestCase> {
     let mut i = 0;
     while i < from_strs.len() {
         let m1 = Matrix::from_str(from_strs[i]).unwrap();
-        let m2 = Matrix::from_str(from_strs[i+1]).unwrap();
-        let mr = Matrix::from_str(from_strs[i+2]).unwrap();
+        let m2 = Matrix::from_str(from_strs[i + 1]).unwrap();
+        let mr = Matrix::from_str(from_strs[i + 2]).unwrap();
         v.push(TestCase {
             test_type: TestCaseType::Add,
             test_data: vec![m1, m2, mr],
@@ -55,7 +76,11 @@ pub fn test_matrix_determinate() -> Result<(), ParseMatrixError> {
 }
 #[test]
 pub fn test_matrix_inverse_on_singular() -> Result<(), ()> {
-    let m = Matrix::new(vec![vec![1.0,2.0,3.0], vec![4.0,5.0,6.0], vec![7.0,8.0,9.0]]);
+    let m = Matrix::new(vec![
+        vec![1.0, 2.0, 3.0],
+        vec![4.0, 5.0, 6.0],
+        vec![7.0, 8.0, 9.0],
+    ]);
     match m.inverse() {
         Some(_inverse) => Err(()),
         None => Ok(()),
@@ -70,14 +95,9 @@ pub fn test_matrix_transpose() -> Result<(), ParseMatrixError> {
 }
 #[test]
 pub fn test_matrix_mul() -> Result<(), ParseMatrixError> {
-    let m1 = Matrix::from_str("1,2\n1,2")?;
-    let m2 = Matrix::from_str("1,3\n2,4")?;
-    let m3 = Matrix::from_str("1,2\n3,4")?;
-    let m4 = Matrix::from_str("1\n2")?;
-    let t1 = Matrix::from_str("5,11\n5,11")?;
-    let t2 = Matrix::from_str("5\n11")?;
-    assert_eq!(&m1 * &m2, t1);
-    assert_eq!(&m3 * &m4, t2);
+    for case in build_mul_test_cases() {
+        assert_eq!(&case.test_data[0] * &case.test_data[1], case.test_data[2]);
+    }
     Ok(())
 }
 #[test]