Vectorize application of xcorr() function

2 ビュー (過去 30 日間)
Howard Wilton
Howard Wilton 2022 年 12 月 3 日
編集済み: Bruno Luong 2022 年 12 月 6 日
For the following code,
t = 0:1e-3:1-1e-3;
AF_hat = [];
fd_ = -8:0.1:8;
for fd = fd_
AF_hat = [AF_hat; xcorr(s,s.*exp(-1i*2*pi*fd*t))*Ts];
end
I would like to eliminate the for loop by doing something like,
xcorr(s,s.*exp(-1i*2*pi*fd_.'*t))*Ts,
but cannot get it to work.
Would welcome any comments/guidance.

採用された回答

Bruno Luong
Bruno Luong 2022 年 12 月 3 日
編集済み: Bruno Luong 2022 年 12 月 3 日
Vectorized method but for-loop with preallocation is faster
t = 0:1e-3:1-1e-3;
Ts = 5e-2;
fd_ = -8:0.1:8;
s = rand(size(t));
tic
AF_hat = zeros(length(fd_),2*length(s)-1);
for k = 1:length(fd_)
fd = fd_(k);
AF_hat(k,:) = xcorr(s,s.*exp(-1i*2*pi*fd*t))*Ts;
end
toc
Elapsed time is 0.074924 seconds.
% vectorize way
tic
A_hat2 = conv2(s,flip(conj(s.*exp(-1i*2*pi*fd_(:).*t))*Ts,2));
toc
Elapsed time is 0.083580 seconds.
% Check correctness
norm(AF_hat-A_hat2,Inf)/norm(AF_hat,Inf)
ans = 6.7209e-16
  1 件のコメント
Bruno Luong
Bruno Luong 2022 年 12 月 6 日
編集済み: Bruno Luong 2022 年 12 月 6 日
May be faster code since avoid conj and replace flip array by 2 vector-flips
t = 0:1e-3:1-1e-3;
Ts = 5e-2;
fd_ = -8:0.1:8;
s = rand(size(t));
% vectorize way
tic
A_hat2 = conv2(s,(Ts*flip(s)).*exp(2i*pi*fd_(:).*flip(t)));
toc
Elapsed time is 0.076804 seconds.

サインインしてコメントする。

その他の回答 (0 件)

製品


リリース

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by