Add is_invertible

matrix.hpp

@@ -145,10 +145,6 @@ public:
     }
     return result;
   }
-  const bool is_unitary() const{
-	  matrix m = this->hermitian_conjugate();
-	  return (*this * m == this->I());
-  }
   // FIXME: This is very dumb
   const vector get_eigenvalues() const {
     if (this->is_diagonal())
@@ -163,6 +159,11 @@ public:
       return false;
     return *this == this->hermitian_conjugate();
   }
+  const bool is_invertible() const { return this->determinant() != 0; }
+  const bool is_unitary() const {
+    matrix m = this->hermitian_conjugate();
+    return (*this * m == this->I());
+  }
   friend std::ostream &operator<<(std::ostream &os, const matrix &m) {
     char last = '\0';
     int longest = 0;