cannam@127: Next: MPI Data Distribution Functions, Previous: MPI Initialization, Up: FFTW MPI Reference [Contents][Index]
cannam@127:Once an MPI plan is created, you can execute and destroy it using
cannam@127: fftw_execute, fftw_destroy_plan, and the other functions
cannam@127: in the serial interface that operate on generic plans (see Using Plans).
cannam@127:
The fftw_execute and fftw_destroy_plan functions, applied to
cannam@127: MPI plans, are collective calls: they must be called for all processes
cannam@127: in the communicator that was used to create the plan.
cannam@127:
You must not use the serial new-array plan-execution functions
cannam@127: fftw_execute_dft and so on (see New-array Execute Functions) with MPI plans. Such functions are specialized to the
cannam@127: problem type, and there are specific new-array execute functions for MPI plans:
cannam@127:
void fftw_mpi_execute_dft(fftw_plan p, fftw_complex *in, fftw_complex *out); cannam@127: void fftw_mpi_execute_dft_r2c(fftw_plan p, double *in, fftw_complex *out); cannam@127: void fftw_mpi_execute_dft_c2r(fftw_plan p, fftw_complex *in, double *out); cannam@127: void fftw_mpi_execute_r2r(fftw_plan p, double *in, double *out); cannam@127:
These functions have the same restrictions as those of the serial
cannam@127: new-array execute functions. They are always safe to apply to
cannam@127: the same in and out arrays that were used to
cannam@127: create the plan. They can only be applied to new arrarys if those
cannam@127: arrays have the same types, dimensions, in-placeness, and alignment as
cannam@127: the original arrays, where the best way to ensure the same alignment
cannam@127: is to use FFTW’s fftw_malloc and related allocation functions
cannam@127: for all arrays (see Memory Allocation). Note that distributed
cannam@127: transposes (see FFTW MPI Transposes) use
cannam@127: fftw_mpi_execute_r2r, since they count as rank-zero r2r plans
cannam@127: from FFTW’s perspective.
cannam@127:
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