1;

function ret=bench_1D(s)
	ret=zeros(size(s));
	for k=1:length(s)
		a=rand(s(k),1);
		tic;
		b=fft(a);
		ret(k)=toc;
		printf("time for %dx1 FFT %f s\n",s(k),ret(k));
		fflush(stdout);
	endfor
endfunction

function calc_and_plot_bench(color)
	n=fftw("threads");
	printf("Number of FFTW threads = %d\n",n);

	s1D = 2.^[18:25];	#powers of 2
	t=bench_1D(s1D);

	leg=sprintf("-o%c;powers of 2 with %d thread(s);",color,n);
	loglog(s1D,t,leg)
	hold on
	xlabel("size")
	ylabel("execution time [s]")

	s1D = 10.^[5:7];	#powers of 10
	t=bench_1D(s1D);
	leg=sprintf("-x%c;powers of 10 with %d thread(s);",color,n);
	loglog(s1D,t,leg)

	#FFTW is best at handling sizes of the form 2^a * 3^b * 5^c * 7^d * 11^e * 13^f, where e+f is either 0 or 
	s1D = [5^6*7^2*11 5^5*7^3*11 5^5*7^3*13 5^7*7^2*11];	
	t=bench_1D(s1D);
	leg=sprintf("-^%c;prime base with %d thread(s);",color,n);
	loglog(s1D,t,leg)
endfunction

hold off

fftw("threads",1);
calc_and_plot_bench('r');

fftw("threads",6);
calc_and_plot_bench('g');

legend("location","northwest")
grid on
print("fftw_bench.png")