gistfile1.txt

using FFTW

const MAX_THREADS = Threads.nthreads()
println("$(MAX_THREADS) threads")

N = 128
M = 40

println("N=$N, M=$M")

xsingle = randn(ComplexF64, N, N, N)
ysingle = copy(xsingle)
xmulti = randn(ComplexF64, N, N, N, M)
ymulti = copy(xmulti)

FFTW.set_num_threads(1)
Pmulti_nothread = plan_fft(xmulti, (1, 2, 3), flags=FFTW.MEASURE)
Psingle_nothread = plan_fft(xsingle, flags=FFTW.MEASURE)

FFTW.set_num_threads(MAX_THREADS)
Pmulti_thread = plan_fft(xmulti, (1, 2, 3), flags=FFTW.MEASURE)
Psingle_thread = plan_fft(xsingle, flags=FFTW.MEASURE)

function FFTs_auto(y, x, Pmulti)
    mul!(y, Pmulti, x)
end
function FFTs_manual(y, x, Psingle)
    for m = 1:size(x, 4)
        @views mul!(y[:, :, :, m], Psingle, x[:, :, :, m])
    end
end
function FFTs_manual_threaded(y, x, Psingle)
    Threads.@threads for m = 1:size(x, 4)
        @views mul!(y[:, :, :, m], Psingle, x[:, :, :, m])
    end
end

println("Single FFT: no threads")
@btime mul!($ysingle, $Psingle_nothread, $xsingle)
println("Single FFT: threads")
@btime mul!($ysingle, $Psingle_thread, $xsingle)




println("Multiple FFTs: manual, no threads")
@btime FFTs_manual($ymulti, $xmulti, $Psingle_nothread)

println("Multiple FFTs: manual_threaded, no threads")
@btime FFTs_manual_threaded($ymulti, $xmulti, $Psingle_nothread)

println("Multiple FFTs: auto, no threads")
@btime FFTs_auto($ymulti, $xmulti, $Pmulti_nothread)



println("Multiple FFTs: manual, threads")
@btime FFTs_manual($ymulti, $xmulti, $Psingle_thread)

println("Multiple FFTs: manual_threaded, threads")
@btime FFTs_manual_threaded($ymulti, $xmulti, $Psingle_thread)

println("Multiple FFTs: auto, threads")
@btime FFTs_auto($ymulti, $xmulti, $Pmulti_thread)


nothing