Is it faster to use array size as an input or calculate size

Question

Josh on 10 Apr 2015

0
Link

Direct link to this question

https://nl.mathworks.com/matlabcentral/answers/197175-is-it-faster-to-use-array-size-as-an-input-or-calculate-size

Edited: James Tursa on 10 Apr 2015

I have a function which will be called many times and performs operations on an array. The function is dependent on the size of the array. Is it faster to calculate the size before implementing the function, or just use the size command as the first step of the function? Thanks

0 Comments
Show -2 older commentsHide -2 older comments

Sign in to comment.

Sign in to answer this question.

Answer 1

James Tursa on 10 Apr 2015

1
Link

Direct link to this answer

https://nl.mathworks.com/matlabcentral/answers/197175-is-it-faster-to-use-array-size-as-an-input-or-calculate-size#answer_174753

Edited: James Tursa on 10 Apr 2015

For ease of use, typically the size would be generated inside the function to make sure there was no mismatch. For speed, this choice is likely in the noise and may not matter where you do it. How simple is your function? Does the array argument change size during the execution of the program? Etc. If you are concerned about speed then use the profiler to determine where to concentrate your efforts. It is probably not with that line.