feat: matrix math

mul: impl Mul for LHS: i32, RHS: Matrix
trait: trait MatrixMath definition for cofactor, minors, adjoint,
determinant

3 files changed, 87 insertions, 44 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 748ca1b..fb67823 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,7 +9,7 @@
 //!
 //! Examples:
 //! ```
-//! use matrix::Matrix;
+//! use matrix::{Matrix, MatrixMath};
 //! use std::str::FromStr;
 //! let m = Matrix::from_str("1,2,3\n4,5,6\n7,8,9").expect("Expected this to work");
 //! println!("Matrix string formatting:\n{}", m);
@@ -24,8 +24,11 @@ pub mod error;
 #[cfg(test)]
 mod tests;
 
-pub use matrix::Matrix;
+pub use matrix::{Matrix, MatrixMath};
 
 pub fn test() {
     println!("Testing code here");
+    let m = Matrix::from(vec![1,2,3,4,5]);
+    m.transpose();
+    m.determinant();
 }
diff --git a/src/matrix.rs b/src/matrix.rs
index bd6b38f..04a01bf 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -11,13 +11,12 @@
 //! ```
 //! TODO:: Create matrix multiplication method
 
+use crate::error::{MatrixSetValueError, ParseMatrixError};
 use std::{
     fmt::Display,
     ops::{Add, Mul, Sub},
     str::FromStr,
 };
-
-use crate::error::{MatrixSetValueError, ParseMatrixError};
 #[derive(Debug, PartialEq, Eq)]
 pub struct Matrix {
     /// Number of rows in matrix.
@@ -29,6 +28,71 @@ pub struct Matrix {
     /// Data stored in the matrix, you should not access this directly
     data: Vec<Vec<i32>>,
 }
+
+pub trait MatrixMath {
+    fn inverse(&self) -> Matrix {
+        (1 / (self.determinant())) * &self.adjoint()
+    }
+    /// Finds the matrix of cofactors for any N-by-N matrix
+    fn cofactor(&self) -> Matrix {
+        todo!();
+    }
+    /// Finds the matrix of minors for any N-by-N matrix.
+    fn minor(&self) -> Matrix {
+        todo!();
+    }
+    /// Finds the determinant of any N-by-N matrix.
+    fn determinant(&self) -> i32 {
+        todo!();
+    }
+    /// Finds the transpose of any matrix.
+    fn transpose(&self) -> Matrix {
+        todo!();
+    }
+    /// Finds the adjoint matrix (transpose of cofactors) for any N-by-N matrix.
+    fn adjoint(&self) -> Matrix {
+        self.cofactor().transpose()
+    }
+}
+impl MatrixMath for Matrix {
+    /// Evaluates any N-by-N matrix.
+    ///
+    /// This function panics if the matrix is not square!
+    fn determinant(&self) -> i32 {
+        if !self.is_square() {
+            panic!()
+        };
+        if self.nrows == 2 && self.ncols == 2 {
+            return self.data[0][0] * self.data[1][1] - self.data[0][1] * self.data[1][0];
+        }
+        let mut tmp = 0;
+        for (i, n) in self.data[0].iter().enumerate() {
+            let mult = if i % 2 == 0 { -*n } else { *n };
+            let eval = self.splice(i).determinant();
+            tmp += mult * eval;
+        }
+        tmp
+    }
+
+    /// Evaluates the tranpose of the matrix.
+    ///
+    /// Each row becomes a column, each column becomes a row.
+    fn transpose(&self) -> Matrix {
+        let mut new_data = Vec::<Vec<i32>>::new();
+        for i in 0..self.nrows {
+            let mut new_row = Vec::<i32>::new();
+            for j in 0..self.ncols {
+                new_row.push(self.data[j][i]);
+            }
+            new_data.push(new_row);
+        }
+        Matrix {
+            nrows: self.ncols,
+            ncols: self.nrows,
+            data: new_data,
+        }
+    }
+}
 impl Matrix {
     /// Matrix initialiser function.
     ///
@@ -69,7 +133,7 @@ impl Matrix {
     pub fn is_square(&self) -> bool {
         self.nrows == self.ncols
     }
-    fn splice(&self, at_index: usize) -> Matrix {
+    pub fn splice(&self, at_index: usize) -> Matrix {
         let mut data: Vec<Vec<i32>> = Vec::new();
         for i in 0..self.data.len() {
             if i == 0 {
@@ -86,44 +150,6 @@ impl Matrix {
         }
         Matrix::new(data)
     }
-
-    /// Evaluates any N-by-N matrix.
-    ///
-    /// This function panics if the matrix is not square!
-    pub fn determinant(&self) -> i32 {
-        if !self.is_square() {
-            panic!()
-        };
-        if self.nrows == 2 && self.ncols == 2 {
-            return self.data[0][0] * self.data[1][1] - self.data[0][1] * self.data[1][0];
-        }
-        let mut tmp = 0;
-        for (i, n) in self.data[0].iter().enumerate() {
-            let mult = if i % 2 == 0 { -*n } else { *n };
-            let eval = self.splice(i).determinant();
-            tmp += mult * eval;
-        }
-        tmp
-    }
-
-    /// Evaluates the tranpose of the matrix.
-    ///
-    /// Each row becomes a column, each column becomes a row.
-    pub fn transpose(&self) -> Matrix {
-        let mut new_data = Vec::<Vec<i32>>::new();
-        for i in 0..self.nrows {
-            let mut new_row = Vec::<i32>::new();
-            for j in 0..self.ncols {
-                new_row.push(self.data[j][i]);
-            }
-            new_data.push(new_row);
-        }
-        Matrix {
-            nrows: self.ncols,
-            ncols: self.nrows,
-            data: new_data,
-        }
-    }
 }
 impl FromStr for Matrix {
     type Err = ParseMatrixError;
@@ -192,6 +218,20 @@ impl<'a, 'b> Sub<&'b Matrix> for &'a Matrix {
         todo!()
     }
 }
+impl<'a> Mul<&'a Matrix> for i32 {
+    type Output = Matrix;
+    fn mul(self, rhs: &'a Matrix) -> Self::Output {
+        let mut d: Vec<Vec<i32>> = Vec::new();
+        for r in &rhs.data {
+            let mut nr: Vec<i32> = Vec::new();
+            for v in r {
+                nr.push(self * v);
+            }
+            d.push(nr);
+        }
+        Matrix::new(d)
+    }
+}
 impl<'a, 'b> Mul<&'b Matrix> for &'a Matrix {
     type Output = Matrix;
     fn mul(self, rhs: &'b Matrix) -> Self::Output {
diff --git a/src/tests/matrix_test_ops.rs b/src/tests/matrix_test_ops.rs
index fe8c40d..e207c3e 100644
--- a/src/tests/matrix_test_ops.rs
+++ b/src/tests/matrix_test_ops.rs
@@ -1,6 +1,6 @@
 use std::str::FromStr;
 
-use crate::{matrix::Matrix, error::ParseMatrixError};
+use crate::{error::ParseMatrixError, matrix::Matrix, MatrixMath};
 
 #[test]
 pub fn test_matrix_add() -> Result<(), ParseMatrixError> {