Only update is_charge_density when explicitely given
Commit c51ebff5 added an is_charge_density
option to LinearProblem.update()
, which causes an unintended change of behavior in old code: when is_charge_density
is not passed as an argument it is still set to True
.
This MR makes sure that is_charge_density
is only updated when explicitly passed as an argument, such that the module is compatible with both old (unchanged) code and newly written code.