# Kalray Inc.: http://www.kalrayinc.com/
#
# Bostan Fast-Fourier Transform Implementation (64K complex-float)
# Developped by J. Hascoet


# Description:
#   This distributed FFT implementation uses the 6-step method to split the work
#   over the compute clusters of the MPPA processor.
#   The FFT 6-step method well described in [1] page 7.
#   However our current implementation supports input array multiple of 4 in order
#   to have square matrix to transpose (transpose is step 1, 3 and 6 of the 6-step)
#   In this benchmark the IO generates input buffer in the DDR.
#       The input array is a complex array (1D array) where the imaginary part
#   is zeros and the real part uses random numbers.
#   First, the compute clusters get a tile of the 1D array interpreted as a
#   2D array (tiling).
#   Second, the CC all execute the 6-step FFTs. All twiddle factors are pre-computed.
#   Finally the result is writen back to the DDR in the IO which executes
#   a sequential FFT and performs correctness check.
# References:
#   [1] 'https://www.nas.nasa.gov/assets/pdf/techreports/1989/rnr-89-004.pdf'

# Performance measures.
#   We measure performance of both DDR access time (I/O) and the computation
#   on the MPPA matrix.
#   There is no batching (batch-1) thus the throughput is the same as the
#   latency. It is a low-latency implementation.
#   The time for initializing the LUT of the twiddle factor is not computed
#   (system initialization).

# Requirements:
#   This benchmark requires Kalray's AccessCore Toolchain and Kalray's MPPA
#   Validated with Kalray's AccessCore >= 2.9.0

# Multi-cluster - Matrix topology condition
#  Only nb_cluster=1, 2, 4, 8 or 16 are supported (selected at build time)
# Intra-cluster
#   The number of core can be from 1 to 16. (nb_core variable at build time)

# How to execute on MPPA hardware
#   By default 16 clusters and 16 cores in each cluster are used.
#   Using only jtag (no pcie, standalone mode)

make nb_core=<NUM_CORE> nb_cluster=<NUM_CLUSTER> [stand_alone_board=<ab01|ab04>] run_jtag

# Using pcie

make nb_core=<NUM_CORE> nb_cluster=<NUM_CLUSTER> run_pcie