Implemented matrix multiplication, added tests for matrix mul and iter

src/math/matrix/arithemtic.rs

@@ -4,6 +4,24 @@ use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssi
 
 use num::{traits::NumAssign, Num, Signed};
 
+impl<T: Num + Clone> Matrix<T> {
+    pub fn multiply(&self, rhs: &Self) -> Self {
+        if !self.can_mul(&rhs) {
+            panic!("Unable to multiply matrices with sizes {}x{} and {}x{}",
+                self.width, self.height(), rhs.width, rhs.height());
+        }
+        let mut new = Matrix::new_zeroes(rhs.width, self.height());
+        for (i, j) in new.indices() {
+            let new_elem = self.row(i).into_iter()
+                .zip(rhs.column(j).into_iter())
+                .map(|(e1, e2)| e1 * e2)
+                .reduce(|acc, e| acc + e);
+            new[i][j] = new_elem.unwrap();
+        }
+        return new;
+    }
+}
+
 impl<T: Num + Clone> Add for Matrix<T> {
     type Output = Self;
     fn add(self, rhs: Self) -> Self::Output {
@@ -109,15 +127,7 @@ impl<T: NumAssign + Clone> DivAssign<T> for Matrix<T> {
 impl<T: Num + Clone> Mul for Matrix<T> {
     type Output = Self;
     fn mul(self, rhs: Self) -> Self::Output {
-        if !self.can_mul(&rhs) {
+        self.multiply(&rhs)
-            panic!("Unable to multiply matrices with sizes {}x{} and {}x{}",
-                self.width, self.height(), rhs.width, rhs.height());
-        }
-        let mut new = Matrix::new_zeroes(rhs.width, self.height());
-        for (i, j) in new.indices() {
-            todo!()
-        }
-        return new;
     }
 }
 
@@ -190,8 +200,50 @@ mod tests {
 
     #[test]
     #[should_panic(expected = "Unable to multiply")]
-    fn mul() {
+    fn mul_wrong_size() {
+        let _ = matrix![2; 1, 2, 3, 4] * matrix![2; 1, 2, 3, 4, 5, 6];
+    }
 
+    #[test]
+    fn mul() {
+        let first = matrix![3;
+            1, 2, 3,
+            4, 5, 6,
+            7, 8, 9
+        ];
+        let second = matrix![3;
+            2, 3, 4,
+            5, 6, 7,
+            8, 9, 10
+        ];
+        assert_eq!(first.multiply(&second), matrix![3;
+            36, 42, 48,
+            81, 96, 111,
+            126, 150, 174
+        ]);
+        assert_eq!(second * first, matrix![3;
+            42, 51, 60,
+            78, 96, 114,
+            114, 141, 168
+        ]);
+        let first = matrix![3;
+            1, 2, 3,
+            4, 5, 6
+        ];
+        let second = matrix![2;
+            2, 3,
+            4, 5,
+            6, 7
+        ];
+        assert_eq!(first.multiply(&second), matrix![2;
+            28, 34,
+            64, 79
+        ]);
+        assert_eq!(second * first, matrix![3;
+            14, 19, 24,
+            24, 33, 42,
+            34, 47, 60    
+        ])
     }
 }
 

src/math/matrix/iter.rs

@@ -120,7 +120,6 @@ impl<'a, T: Num> Iterator for ColumnsIter<'a, T> {
     }
 }
 
-
 impl Iterator for IterIndices {
     type Item = (usize, usize);
     fn next(&mut self) -> Option<Self::Item> {
@@ -139,7 +138,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn iter() {
+    fn iter_elem() {
         let data = vec![1,2,3,4,5,6,7,8,9];
         let mut matrix = Matrix::new(data.clone(), 3);
         for (i, e) in matrix.iter().enumerate() {
@@ -153,5 +152,66 @@ mod tests {
             assert_eq!(data[i] + 2, e);
         }
     }
+
+    #[test]
+    fn iter_indexed() {
+        let data = vec![1,2,3,4,5,6,7,8,9];
+        let mut matrix = Matrix::new(data.clone(), 3);
+        let (width, height) = (matrix.width(), matrix.height());
+        let mut matrix_iter = matrix.iter_indexed();
+        for i in 0..height {
+            for j in 0..width {
+                let (mi, mj, e) = matrix_iter.next().unwrap();
+                assert_eq!((mi, mj), (i, j));
+                assert_eq!(*e, data[i * width + j]);
+            }
+        }
+        let mut matrix_iter = matrix.iter_indexed_mut();
+        for i in 0..height {
+            for j in 0..width {
+                let (mi, mj, e) = matrix_iter.next().unwrap();
+                assert_eq!((mi, mj), (i, j));
+                assert_eq!(*e, data[i * width + j]);
+                *e += 2;
+                assert_eq!(*e, data[i * width + j] + 2);
+            }
+        }
+    }
+
+    #[test]
+    fn iter_rows() {
+        let mut matrix = matrix![3;
+            1, 2, 3,
+            4, 5, 6,
+            7, 8, 9
+        ];
+        let mut matrix_iter = matrix.iter_rows();
+        assert_eq!(matrix_iter.next().unwrap(), &[1, 2, 3]);
+        assert_eq!(matrix_iter.next().unwrap(), &[4, 5, 6]);
+        assert_eq!(matrix_iter.next().unwrap(), &[7, 8, 9]);
+        assert_eq!(matrix_iter.next(), None);
+        for row in matrix.iter_rows_mut() {
+            row[0] += 9;
+        }
+        let mut matrix_iter = matrix.iter_rows_mut();
+        assert_eq!(matrix_iter.next().unwrap(), &[10, 2, 3]);
+        assert_eq!(matrix_iter.next().unwrap(), &[13, 5, 6]);
+        assert_eq!(matrix_iter.next().unwrap(), &[16, 8, 9]);
+        assert_eq!(matrix_iter.next(), None);
+    }
+
+    #[test]
+    fn iter_columns() {
+        let matrix = matrix![3;
+            1, 2, 3,
+            4, 5, 6,
+            7, 8, 9
+        ];
+        for (j, column) in matrix.iter_columns().enumerate() {
+            for (i, e) in column.enumerate() {
+                assert_eq!(*e, matrix[i][j]);
+            }
+        }
+    }
 }