Input

• a - Parallel array that is to be transformed. Its rank, extents, and type must be the same as the parallel array (a) supplied in the S3L_fft_setup call.

• setup_id - Scalar integer variable. Use the value returned by the S3L_fft_setup call for this argument.

• iflag - Determines the transform direction. Set iflag to 1 for forward FFT; set to -1 for inverse FFT.

• axis - Determines the axis along which the FFT is to be computed.