# Efficiency help 2

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Andy 2011 年 12 月 7 日
for q = 1:length(maxtab2)
for r = 1: length(maxtab2{q})
for s = 1: length(replacewith)
if abs (maxtab2{q}(r) - replacewith(s)) ==1
maxtab2{q}(r) = replacewith(s);
end
end
end
end
maxtab2 is a list of cells, each containing 2 colums of numbers(up to 20 numbers each column).
length(maxtab2)=190 length(maxtab2{q}) would be up to 20
can anyone help me make the 3 loops more effecient please? It is taking way too long right now, Thanks!
here is the data for maxtab2, its just the content of 1 cell
{[705;4000]}
replacewith is a list of over 5000 variables. the code here chooses one of these 5000 variable and replace the corresponding maxtab2 (determined by the for loops) with the chosen variable from replacewith
##### 2 件のコメント表示非表示 1 件の古いコメント
Sean de Wolski 2011 年 12 月 7 日
I agree with Sven. Why?
"Because the mathematician knew it was a good idea."

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### 採用された回答

Sean de Wolski 2011 年 12 月 7 日
for s
if abs (maxtab2{q}(r) - replacewith(s)) ==1
maxtab2{q}(r) = replacewith(s);
end
end
I'm pretty sure this can be replaced with
maxtab{q}(r) = find(abs(maxtab{q}(r)-replacewith)==1,1,'last')
but this operation seems wierd to me. You're going to replace it with the value one less than it or one more than it, you're aware of this right?
##### 9 件のコメント表示非表示 8 件の古いコメント
Andy 2011 年 12 月 7 日
i ended up using this: works well
for q=1:length(maxtab2)
for r = 1:length(maxtab2{q})
finding = abs(maxtab2{q}(r) - replacewith(1:length(replacewith)));
if ismember (1,finding)==1
maxtab2{q}(r)=replacewith(find(finding==1,1,'last'));
end
end
end

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### その他の回答 (1 件)

Jerry 2011 年 12 月 7 日
If this maxtab2 can be stored in a matrix. This whole thing can be done without iteration. But if it's a cell, I think it's pretty hard to speed it up since a lot of operations cannot be applied to cell, like "-"(minus), and "find".
##### 1 件のコメント表示非表示 なし
Andy 2011 年 12 月 7 日
maxtab2 is a list of cells, and each cell contains two colums, one columns is x-axis coordinate, the other is y-axis coordinate

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