This is a workaround for an issue with decltype function templates in thrustshift:
https://github.com/codecircuit/thrustshift/blob/master/include/thrustshift/COO.h#L910-L913
which leads to
error: no instance of function template "thrustshift::symmetrize_abs_and_make_pattern_symmetric" matches the argument listwhen used in magma. The v1 symmetrization seems unaffected.