Conditional calculations on a numeric matrix
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Hi All,
I'm relatively new to Matlab and I find myself slightly stuck. I have a numeric matrix of numbers comprising of floating point values. Depending on whether the value in each cell is less than or greater than some threshold value, either one or another calculation is made.
Below is a much simplified expression of my problem but it illustrates the form of what I'm trying to do with millions of cells of values which takes a rather longer time than the illustration below.
I realise that I can make a logic matrix from the input matrix but then I'm stuck on what follows to complete the calculations.
Any advice is gratefully received.
input = magic(10);
thresholdvalue = 50;
for col = 1 : 10
for row = 1 : 10
if input(row,col) > thresholdvalue
result(row,col) = input(row,col)*2;
else
result(row,col) = input(row,col)/2;
end
end
end
采纳的回答
Walter Roberson
2019-11-18
mask = input > thresholdvalue;
result(mask) = input(mask) * 2;
result(~mask) = input(mask) / 2;
2 个评论
Wah On Ho
2019-11-18
Walter Roberson
2019-11-18
Ah, yes, sorry, I did have a typo there.
result(~mask) = input(~mask) / 2;
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