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Asked: 2026-05-23T15:08:13+00:00

I have some code that is taking a long time to run(several hours) and

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I have some code that is taking a long time to run(several hours) and I think it is because it is doing a lot of comparisons in the if statement. I would like it to run faster, does anyone have any helpful suggestions to improve the runtime? If anyone has a different idea of what is slowing the code down so I could try and fix that it would be appreciated. 

xPI = zeros(1,1783);
argList2 = zeros(1,1783);
aspList2 = zeros(1,1783);
cysList2 = zeros(1,1783);
gluList2 = zeros(1,1783);
hisList2 = zeros(1,1783);
lysList2 = zeros(1,1783);
tyrList2 = zeros(1,1783);

minList= xlsread('20110627.xls','CM19:CM25');
maxList= xlsread('20110627.xls','CN19:CN25');
N = length(pIList);
for i = 1:N
    if (argList(i)>= minList(1) && argList(i) <= maxList(1)) ...
        && (aspList(i)>= minList(2) && aspList(i) <= maxList(2)) ...
        && (cysList(i)>= minList(3) && cysList(i) <= maxList(3)) ...
        && (gluList(i)>= minList(4) && gluList(i) <= maxList(4)) ...
        && (hisList(i)>= minList(5) && hisList(i) <= maxList(5)) ...
        && (lysList(i)>= minList(6) && lysList(i) <= maxList(6)) ...
        && (tyrList(i)>= minList(7) && tyrList(i) <= maxList(7))

        xPI(i) = pIList(i);
        argList2(i) = argList(i);
        aspList2(i) = aspList(i);
        cysList2(i) = cysList(i);
        gluList2(i) = gluList(i);
        hisList2(i) = hisList(i);
        lysList2(i) = lysList(i);
        tyrList2(i) = tyrList(i);
        disp('passed test');
    end
end
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1 Answer

  1. Editorial Team

    You can try vectorising the code; I have made up some sample data sets and duplicated some of the operations you’re performing below.

    matA1 = floor(rand(10)*1000); 
matB1 = floor(rand(10)*1000);

matA2 = zeros(10); 
matB2 = zeros(10);

minList = [10, 20]; 
maxList = [100, 200];

indicesToCopy = ( matA1 >= minList(1) ) & ( matA1 <= maxList(1) ) & ( matB1 >= minList(2) ) & ( matB1 <= maxList(2) );

matA2(indicesToCopy) = matA1(indicesToCopy); 
matB2(indicesToCopy) = matB1(indicesToCopy);

    No idea whether this is any faster, you’ll have to try it out.

    EDIT:
    This doesn’t matter too much since you’re only making two calls, but xlsread is horribly slow. You can speed up those calls by using this variant syntax of the function.

    num = xlsread(filename, sheet, 'range', 'basic')

    The catch is that the range argument is ignored and the entire sheet is read, so you’ll have to mess with indexing the result correctly.

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