fix the return of the solve_matrix_system method (#7)

* fix the return of the solve_matrix_system method

* update readme file

* format

Author: LucaBonamino

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "lin_algebra"
-version = "0.3.0"
+version = "0.3.1"
 edition = "2021"
 authors = ["LucaBonamino"]
 description = "A linear algebra package to compute image, kernel and rank of linear applications."

README.md

@@ -16,7 +16,7 @@ Add the dependency to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-lin_algebra = "0.2.0"
+lin_algebra = "0.3.1"
 ```
 
 ## Usage

src/gf2_matrix.rs

@@ -189,21 +189,29 @@ impl GF2Matrix {
     /// # Returns
     /// Matrix X such that self * X = Y.
     pub fn solve_matrix_system(&self, y: &GF2Matrix) -> GF2Matrix {
-        let mut solution: Vec<Vec<u8>> = Vec::new();
         if self.rank() < self.ncols() {
             panic!("Matrix must have full rank");
         }
+
         let (ech, operations) = self.echelon_form();
         let to_remove = ech.nrows() - ech.rank();
-        for i in 0..y.ncols() {
-            let mut solved_b = Self::apply_operations(&operations, &y.column(i));
+
+        let n_rows = self.ncols();
+        let n_cols = y.ncols();
+
+        let mut elements = vec![vec![0u8; n_cols]; n_rows];
+        for j in 0..y.ncols() {
+            let mut solved_b = Self::apply_operations(&operations, &y.column(j));
             for _ in 0..to_remove {
                 solved_b.remove(solved_b.len() - 1);
             }
-            solution.push(solved_b);
+
+            for i in 0..n_rows {
+                elements[i][j] = solved_b[i];
+            }
         }
 
-        GF2Matrix::new(solution)
+        GF2Matrix::new(elements)
     }
 
     /// Solves for X such that equation A*x = b where A  is a GF2Matrix and b a Vec<u8>.

src/lib.rs

@@ -150,7 +150,7 @@ mod tests {
         let r = m.solve_matrix_system(&rm);
         assert_eq!(
             r.elements,
-            vec![vec![0, 1, 1], vec![0, 0, 1], vec![1, 1, 0]]
+            vec![vec![0, 0, 1], vec![1, 0, 1], vec![1, 1, 0]]
         );
     }
 
@@ -165,7 +165,7 @@ mod tests {
         let r = m.solve_matrix_system(&rm);
         assert_eq!(
             r.elements,
-            vec![vec![0, 1, 1], vec![0, 0, 1], vec![1, 1, 0]]
+            vec![vec![0, 0, 1], vec![1, 0, 1], vec![1, 1, 0]]
         );
     }