#### 4.4.3 Advanced Real-to-real Transforms ¶

    fftw_plan fftw_plan_many_r2r(int rank, const int *n, int howmany,
                                 double *in, const int *inembed,
                                 int istride, int idist,
                                 double *out, const int *onembed,
                                 int ostride, int odist,
                                 const fftw_r2r_kind *kind, unsigned flags);

Like `fftw_plan_many_dft`, this function adds `howmany`, `nembed`, `stride`, and `dist` parameters to the `fftw_plan_r2r` function, but otherwise behaves the same as the basic interface. The interpretation of those additional parameters is the same as for `fftw_plan_many_dft`. (Of course, the `stride` and `dist` parameters are now in units of `double`, not `fftw_complex`.)

Arrays `n`, `inembed`, `onembed`, and `kind` are not used after this function returns. You can safely free or reuse them.