Poisson solve in master giving incorrect result
A long-time run of both the reference and optimized versions shows instabilities for Vlasov4. Upon investigation, it seems the electric field does not compare well with the matlab solution after the very first solve of the electric field. The b and DeltaX look to match, so I'm unsure where the problem lies.
I tried comparing the factors with those computed via matlab (
[L,U]=lu(DeltaX); factors=L+U;), and they do seem different, but I'm not sure if that's a great comparison.
Just writing this down here so I don't forget the problem details.