#### 6.12.6 MPI Wisdom Communication

To facilitate synchronizing wisdom among the different MPI processes, we provide two functions:

    void fftw_mpi_gather_wisdom(MPI_Comm comm);
    void fftw_mpi_broadcast_wisdom(MPI_Comm comm);

The `fftw_mpi_gather_wisdom` function gathers all wisdom in the given communicator `comm` to the process of rank 0 in the communicator: that process obtains the union of all wisdom on all the processes. As a side effect, some other processes will gain additional wisdom from other processes, but only process 0 will gain the complete union.

The `fftw_mpi_broadcast_wisdom` does the reverse: it exports wisdom from process 0 in `comm` to all other processes in the communicator, replacing any wisdom they currently have.

See FFTW MPI Wisdom.