A very stupid first start of get_eigenvalues

matrix.hpp

@@ -121,6 +121,24 @@ public:
     }
     return m;
   }
+  const bool is_diagonal() {
+    bool result = true;
+    if (this->num_entries != this->entry_dimension)
+      return !result;
+    for (long long i = 0; i < this->num_entries; i++) {
+      for (long long j = 0; j < this->num_entries; j++) {
+        if (i != j && this->entries[i][j] != 0)
+          return !result;
+      }
+    }
+    return result;
+  }
+  // Fixme: This is very dumb
+  const vector get_eigenvalues() {
+	  if (this->is_diagonal())
+		  return this->get_diagonal();
+	  return vector(0);
+  }
   const bool is_eigenvalue(cnumber z) const {
     return ((*this - (this->I() * z)).determinant() == 0);
   }