how to speed my code up

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Hello everone,

Here, line 4 and 5 is called 5525575680 times and they last 280 and 230 seconds in order. May I speed it up, how can I use it more efficient ?

  function  [utilization] = totalUtilization(myArray, periodNumber, count, LPP)
     duration = 0;
     for i = 1:count
          duration = duration + myArray(periodNumber, i);
     end
     utilization = duration / LPP;
  end

Thanks in advance.

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cglr 2019-11-16

Because, I still can't get used to ability of MATLAB :) .

You are exactly true and no need to loop for sum or etc. I wrote the function taking into account to your comment:

utilization = sum(myArray(periodNumber,:)) / LPP;

Thank you so much.

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Answer 1

Daniel M 2019-11-16

编辑：Daniel M 2019-11-16

在 MATLAB Online 中打开

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Why do you need a loop to compute a sum? Just replace the entire function with

utilization = sum(myArray(periodNumber, 1:count)) / LPP;

And if count is equal to the number of columns of myArray, replace "1:count" with just ":" to avoid making an extra temporary index.

If periodNumber happens to be a vector, then include the number 2 as the dimension input into sum.

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cglr 2019-11-17

actually table is a regular array with the size (period,telCount). And I can ask the question in a better way as seen below:

x = zeros(period,1);

for i=1:period

x(i,1) = sum(table(i,1:telCount));

end

Here what I want is, sum all column for each row and write result to x array.

Daniel M 2019-11-17

You really enjoy writing loops! But you don't need to. Look up the documentation for the sum function. It shows you how to do just that.

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