clear all
close all

%Compare native FFT2 with cuda implementation
FFTsize=[256 512 1024 2048 3072];
sim_runs=10;

time_fft2_matlab=zeros(sim_runs,length(FFTsize));
time_fft2_cuda=zeros(sim_runs,length(FFTsize));
cuda_error=zeros(sim_runs,length(FFTsize));
matlab_error=zeros(sim_runs,length(FFTsize));
for ii=1:length(FFTsize)

    for iii=1:sim_runs
        a=rand(FFTsize(ii))+i*rand(FFTsize(ii));

        tic;b_matlab=fft2(a);
        time_fft2_matlab(iii,ii)=toc;


        tic;b_cuda=fft2_cuda(a);
        time_fft2_cuda(iii,ii)=toc;

        x=abs(a-ifft2_cuda(b_cuda));
        cuda_error(iii,ii)=mean(x(:));

        x=abs(a-ifft2(b_matlab));
        matlab_error(iii,ii)=mean(x(:));
    end

    disp(['IFFT2(FFT2(X[' num2str(FFTsize(ii)) ' by ' num2str(FFTsize(ii)) '])) with a cuda error of ' num2str(mean(cuda_error(:,ii))) ' and a matlab error of '  num2str(mean(matlab_error(:,ii)))  ])
end


x=a-ifft2_cuda(b_cuda);
figure
subplot(2,2,1)
hist(real(x(:)),1113)
title(['Cuda error histogram for square matrix of size ' num2str(FFTsize(ii))])
xlabel('Error values (real part)')
ylabel('Count')

subplot(2,2,2)
hist(imag(x(:)),1113)
xlabel('Error values (imaginary part)')
ylabel('Count')

x=a-ifft2(b_matlab);
subplot(2,2,3)
hist(real(x(:)),1113)
title(['Matlab error histogram for square matrix of size ' num2str(FFTsize(ii))])
xlabel('Error values (real part)')
ylabel('Count')

subplot(2,2,4)
hist(imag(x(:)),1113)
xlabel('Error values (imaginary part)')
ylabel('Count')