Merge pull request #167 from wermos/fix-det

Fix determinant bug

Author: romeric

Fastor/expressions/linalg_ops/unary_det_op.h

@@ -25,7 +25,7 @@ template<DetCompType DetType = DetCompType::Simple, typename T, size_t M,
     enable_if_t_<is_greater_v_<M,4UL>    && DetType == DetCompType::Simple,bool> = false>
 FASTOR_INLINE T determinant(const Tensor<T,M,M> &a) {
     // Dispatch to LU
-    determinant<DetCompType::LU>(a);
+    return determinant<DetCompType::LU>(a);
 }
 
 // For high order tensors

tests/test_linalg/test_linalg.cpp

@@ -123,6 +123,19 @@ void test_linalg() {
         FASTOR_EXIT_ASSERT(std::abs(det<DetCompType::LU>(A)         - det(A)        ) < HugeTol);
     }
 
+	// big determinant
+	{
+		Tensor<T, 6, 6> M = {{1, 0, 3, 0, 0, 0},
+                             {0, -2, 4, 0, 5, 0},
+                             {0, 0, 3, 0, 0, 0},
+                             {0, 0, 0, 4, 0, 0},
+                             {0, 0, 0, 0, 9, 0},
+                             {-1, -1, -1, -1, -1, -1}
+                             };
+
+		FASTOR_EXIT_ASSERT(std::abs(determinant(M) - 216) < Tol);
+	}
+
     print(FGRN(BOLD("All tests passed successfully")));
 
 }