Sampling iteratively random value from a matrix/array
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k = unique(ID_site)
rl = [0.7 0.8 0.85 0.95 1]
rs = [0.65 0.7 0.75 0.8 0.85 0.9 0.95]
im = [0.55 0.65 0.75 0.85 0.9 0.95 1]
ka = [0.92 1]
for i=1:numel(k)
tc1 = rl.*rs.*im.*ka
tc2 = rl.*rs.*im.*ka
tc3 = rl.*rs.*im.*ka
end
Hello,
I want to calculate the products tc1, tc2 and tc3 several times (10000 nsamples) for each ID_site, sampling each time a random value from rl, rs, im and ka.
The output should display 10000 results of tc1, tc2 and tc3 for each test site.
Does anyone knows how to do that?
Thank you very much
采纳的回答
Stephen23
2019-8-30
No loops required, just use indexing:
k = 1:13; % fake data
n = numel(k);
rl = [0.7 0.8 0.85 0.95 1]
rs = [0.65 0.7 0.75 0.8 0.85 0.9 0.95]
im = [0.55 0.65 0.75 0.85 0.9 0.95 1]
ka = [0.92 1]
% random indices:
rl_x = randi(numel(rl),1,n);
rs_x = randi(numel(rs),1,n);
im_x = randi(numel(im),1,n);
ka_x = randi(numel(ka),1,n);
% output:
out = rl(rl_x) .* rs(rs_x) .* im(im_x) .* ka(ka_x)
3 个评论
Enrico D'Addario
2019-9-2
"Am I wrong?"
So far nothing you have described requires a loop. You can trivially generate the random indices with size 1000x110 and then get all of your results at once.
s = 1000; % number of samples
k = 1:110; % fake data
n = numel(k);
rl = [0.7,0.8,0.85,0.95,1];
rs = [0.65,0.7,0.75,0.8,0.85,0.9,0.95];
im = [0.55,0.65,0.75,0.85,0.9,0.95,1];
ka = [0.92,1];
% random indices:
rl_x = randi(numel(rl),s,n);
rs_x = randi(numel(rs),s,n);
im_x = randi(numel(im),s,n);
ka_x = randi(numel(ka),s,n);
% output:
out = rl(rl_x) .* rs(rs_x) .* im(im_x) .* ka(ka_x);
Enrico D'Addario
2019-9-2
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