Which is faster, a row vector or a column vector? Can anyone answer me please?

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Avan Al-Saffar
Avan Al-Saffar 2015-5-13
编辑： Stephen23 2015-5-15
I am trying to do some integration so I am defining the output as a matrix, my question is which definition will give me faster results to define my matrix :
A = zeros(1,n) or A = zeros(n,1)?
Regards

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Stephen23
Stephen23 2015-5-13
编辑：Stephen23 2015-5-15
Perhaps the column, as MATLAB uses column-major memory storage of arrays. But really it is unlikely to make a big difference.
Just try it and use timeit or tic and toc to compare the times.
Another very fast way to define a matrix of zeros is this:
A(n) = 0;
Or if speed really is that critical, you might like to check out some of the submissions on MATLAB File Exchange:
http://www.mathworks.com/matlabcentral/fileexchange/31362-uninit-create-an-uninitialized-variable--like-zeros-but-faster-
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Walter Roberson
Walter Roberson 2015-5-14
My checking shows that if you use 5 for r, and leave s symbolic, then there is a closed-form integral for the expression -- something that could be evaluated once per t rather than having to do the time-consuming numeric integration.
In the case of r held at 5, the integral for turns complex if s becomes larger than about 10.3 or if s is negative (but might become positive again below -10.3).
When you are varying r and s for your 16 runs, what are the values you are testing with?

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Walter Roberson
Walter Roberson 2015-5-13
For any of the arithmetic operations, a row vector is exactly the same speed as a column vector. However, extracting a column vector from a matrix is faster than extracting a row vector. Also, library functions often are defined as returning column vectors and their logic is sometimes marginally faster on column vectors.

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