Migration to cuFINUFFT v2.2

Between versions 1.3 and 2.2 of cuFINUFFT, the API was updated to align more closely with that of FINUFFT. This was done for both the C and C++ interface as well as for the Python interface. A summary of the API changes will be found below.

C and C++ interface

The following function signatures were updated during the API change:

• cufinufft_makeplan, which previously had the signature

  int cufinufft_makeplan(int type, int dim, int *n_modes, int iflag,
      int ntransf, double tol, int maxbatchsize, cufinufft_plan *plan,
      cufinufft_opts *opts);
  

  and now has the signature

  int cufinufft_makeplan(int type, int dim, const int64_t *n_modes,
      int iflag, int ntr, double eps, cufinufft_plan *d_plan_ptr,
      cufinufft_opts *opts);
  

  In other words, the n_modes argument now takes the type int64_t to accomodate larger arrays and the maxbatchsize argument has been removed (and can now be found as part of cufinufft_opts). The tol and ntransf arguments have also been renamed to eps and ntr, respectively.

• cufinufft_setpts, which had the signature

  int cufinufft_setpts(int M, double* h_kx, double* h_ky, double* h_kz,
      int N, double *h_s, double *h_t, double *h_u, cufinufft_plan d_plan);
  

  and now has the signature

  int cufinufft_setpts(cufinufft_plan d_plan, int M, double *d_x,
      double *d_y, double *d_z, int N, double *d_s, double *d_t, double *d_u);
  

  Aside from name changes, main difference here is that the plan is now the first argument, not the last.

• cufinufft_execute, which had the signature

  int cufinufft_execute(cuDoubleComplex* h_c, cuDoubleComplex* h_fk, cufinufft_plan d_plan);
  

  and now has the signature

  int cufinufft_execute(cufinufft_plan d_plan, cuDoubleComplex *d_c, cuDoubleComplex *d_fk);
  

  Again, the names have changed slightly and the plan argument is moved to be the first argument.

• cufinufft_destroy has not changed its signature.

• cufinufft_default_opts used to have the signature

  int cufinufft_default_opts(int type, int dim, cufinufft_opts *opts);
  

  but now has the signature

  void cufinufft_default_opts(cufinufft_opts *opts);
  

  Consequently, you no longer need to specify the type and dimension when filling out the default options structure.

Note that the above function signature are given for the double-precision API. For single precision, replace the cufinufft_ with cufinufftf_ and occcurences of double with float.

Python interface

One big difference in the Python interface is that cufinufft.cufinufft has been renamed cufinufft.Plan. Its methods have the following updates

• The constructor Plan.__init__ now defaults to dtype="complex64" instead of dtype="float32". The effect is the same (single-precision computations) but now makes explicit that we are dealing with complex (not real) transforms.

• The set_pts method is now called setpts.

• The execute method now takes a data argument and returns its output instead of using c and fk as input/output arguments. An optional out argument is also used to specify an output array.

The new API also includes simple interfaces cufinufft.nufft*d* in the style of finufft.nufft*d*.