Gathers each non-periodic line into a periodic one, so that a plain FFT can stand in for the cosine transform, solves in spectral space, and scatters the result back. The 000 case has nothing to reorder and overrides this to transform f in place.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| class(poisson_fft_t) | :: | self | ||||
| class(field_t), | intent(inout) | :: | f | |||
| class(field_t), | intent(inout) | :: | temp |