Which is faster, a row vector or a column vector? Can anyone answer me please?
72 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Avan Al-Saffar
am 13 Mai 2015
Bearbeitet: Stephen23
am 15 Mai 2015
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
0 Kommentare
Akzeptierte Antwort
Stephen23
am 13 Mai 2015
Bearbeitet: Stephen23
am 15 Mai 2015
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:
7 Kommentare
Walter Roberson
am 14 Mai 2015
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?
Weitere Antworten (1)
Walter Roberson
am 13 Mai 2015
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.
Siehe auch
Kategorien
Mehr zu Logical finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!