fix: fixed incorrect determinant sum

src/types/matrix.rs

@@ -57,25 +57,34 @@ impl 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 == at_index {continue;}
-            let mut r: Vec<i32> = Vec::new(); 
+            if i == 0 {
+                continue;
+            }
+            let mut r: Vec<i32> = Vec::new();
             for j in 0..self.data[i].len() {
-                if j == at_index {continue;}
+                if j == at_index {
+                    continue;
+                }
                 r.push(self.data[i][j]);
             }
             data.push(r);
         }
-        Matrix::new(data)
+        let m = Matrix::new(data);
+        // println!("Splice at {}: {}", at_index, m);
+        m
     }
     pub fn determinant(&self) -> i32 {
+        if !self.is_square() { panic!() };
         if self.nrows == 2 && self.nrows == 2 {
-            return &self.data[0][0] * &self.data[0][1] - &self.data[1][0] * &self.data[1][1];
+            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();
+            // println!("tmp result: {}", mult * eval);
             tmp += mult * eval;
+            // println!("tmp: {}", tmp);
         }
         tmp
     }