added warnings
@@ -257,9 +257,13 @@ class LongDivision(Reciprocal):
if self._negative_evals:
self._neg_offset = 1
+
self._num_ancillae = len(self._ev) - self._neg_offset
self._n = self._num_ancillae + 1
+ if self._num_ancillae < 3:
+ raise NotImplementedError("Min. size of eigenregister is 3 for positive eigenvalues and 4 when negative eigenvalues are enabled")
+
if self._precision is None:
self._precision = self._num_ancillae
