fg_03_05.m

英文书《Digital Signal Processing with Examples in MATLAB》附带的MATLAB实例

% fg_03_05 - plot of FFT flops vs. N.
fid=fopen('FFTtime.txt','r');
[AA,size]=fscanf(fid,'%16f%20e\n',[2 inf]);
fclose(fid);
N=AA(1,:);
f=AA(2,:);
% Make the plot. f(1006)=flops for N=1009 = prime.
scale=[f(1006)/1009^2; f(1021)/5120];
%
sp_fig(1,6,3);
semilogy(N,f,'ok'); grid;
line(N,scale(1)*N.^2,'linewidth',1.4,'color','k');
line(N,scale(2)*(N/2).*log2(N),'linewidth',1.4,'color','k');
set(gca,'fontname','times','fontsize',14);
xlabel('FFT size (N)'); ylabel('flops');