matrix-free Helmholtz operator, ONLY for the default gird system First deal with the boundary grid points and then the internals
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| complex(kind=realdp), | intent(inout), | dimension(1-LAP:nx+LAP,1-LAP:ny+LAP) | :: | v_in | ||
| complex(kind=realdp), | intent(inout), | dimension(1-LAP:nx+LAP,1-LAP:ny+LAP) | :: | v_out |