1 files changed, 25 insertions, 3 deletions
diff --git a/src/matrix.rs b/src/matrix.rs
index c324c36..a81fcf0 100644
--- a/src/matrix.rs
+++ b/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 {