Advice on a few bottlenecks in my code
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According to the profiler, I have four lines of code taking up 99% of my CPU time.
if(statment)
pCond = (bold_Phi(k,2) <= data(thisIdx : idx, 7));
else
pCond = (data(thisIdx : idx, 7) <= bold_Phi(k,2));
end
IDY = find( (data(thisIdx : idx, 1) == -1) & (pCond) & (data(thisIdx : idx, 11) == bold_Phi(k,p + 10)) );
IDZ = find( (dV(thisIdx : idx, :) <= -bold_Phi(k,3)) & (pCond) & (sCond) );
where bold_Phi and data are 2D matrices and dV is a vector.
I dont think the time penalty is coming from the indexing as the following statement is very quick
~isnan(data(thisIdx : idx, 3));
anything obvious I have missed that will help me speed up these few statements?
thank you
4 个评论
Matt Kindig
2013-2-21
How large are bold_Phi and dV?
Matlab2010
2013-2-22
Sean de Wolski
2013-2-22
What is statement?
Matlab2010
2013-2-22
编辑：Matlab2010
2013-2-22
回答（2 个）
Kye Taylor
2013-2-21
If you don't need the actual indices, you can omit the find command to save time. In particular, notice that the following code blocks are equivalent but the first does not use find:
data = rand(1000,1);
isBig = data>0.5;
bigData = data(isBig);
and
data = rand(1000,1);
isBigIdx = find(data>0.5);
bigData2 = data(isBigIdx);
1 个评论
Matlab2010
2013-2-22
Mark Whirdy
2013-2-22
编辑：Mark Whirdy
2013-2-22
0 个投票
(Almost-) Never use the find() function!
I'd need to see the contents of the variables, but at first glance you can maybe just remove it altogether with same functionality?
0 个评论
此问题已关闭。
2013-2-21
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2021-8-20
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