copy-paste assignment 2~5

src/assignments/assignment02_grade.rs

@@ -149,6 +149,48 @@ mod test {
         assert_eq!(fibonacci(92), 12200160415121876738);
     }
 
+    // Equivalence between two floating-point matrices, as element-wise equivalence
+    use std::cmp::PartialEq;
+    impl PartialEq for FMat2 {
+        fn eq(&self, other: &FMat2) -> bool {
+            self.a == other.a && self.b == other.b && self.c == other.c && self.d == other.d
+        }
+    }
+
+    #[test]
+    fn test_inverse() {
+        assert_eq!(
+            FMat2 {
+                a: 1.0,
+                b: 1.0,
+                c: 2.0,
+                d: 3.0
+            }
+            .inverse(),
+            FMat2 {
+                a: 3.0,
+                b: -1.0,
+                c: -2.0,
+                d: 1.0
+            }
+        );
+        assert_eq!(
+            FMat2 {
+                a: 2.0,
+                b: 3.0,
+                c: 5.0,
+                d: 7.0
+            }
+            .inverse(),
+            FMat2 {
+                a: -7.0,
+                b: 3.0,
+                c: 5.0,
+                d: -2.0
+            }
+        );
+    }
+
     #[test]
     fn test_lyrics() {
         assert_eq!(twelve_days_of_christmas_lyrics(), LYRICS)