Exchanging data

All routines work on the structure my_plan. One can exchange data with this structure if one wants to use several transforms. One can do this by declaring, allocating memory (fftw_malloc), initiatisation (optionally) and using the SWAPC macro, e.g.

SWAPC(my_plan.f_hat,new_f_hat).

Note that the data has the right type and size (see Table 4). Memory deallocation of all 'free' data has to be done by the user's program. Note, that the vectors my_plan.g and my_plan.g_hat must not be exchanged.