Ensure that iteration is the same length for preconditioner #129

Job	Run time
Build wheels for linux-arm	2m 30s
Build wheels for linux-intel	2m 22s
Build source distribution	14s
Build wheels for macos-arm	6m 9s
Build wheels for windows	4m 13s
Publish Python distribution to PyPI	-1s
	15m 27s

Provide feedback