How to calculate the computational complexity

hi,

I am segmenting images using region growing, Otsu methods, Fuzzy c mean methods, I wondering that how can i calculate the computational complexity of these methods? and how I can categorize in terms of performance using computational complexity? I have seen many links talking about complexity like O(n), O(n^2) Whats the difference and How I can know the complexity for my above listed methods.

Please Suggest !

[VELAMMAL SHIVSHANKAR]

Hello
https://in.mathworks.com/matlabcentral/fileexchange/43707-computational-complexity
Refer This Link. It may help you!!

Answer 1

[Muhammad Ali Qadar]

 tic

....//code

 toc

[Walter Roberson]

This has almost nothing to do with computational complexity.

[Dan Po]

lol

[Ge Shi]

It can only help you get the time consumption for running the code.

Answer 2

[Walter Roberson]

There is no mechanical way to calculate computational complexity.

For more information see http://en.wikipedia.org/wiki/Computational_complexity_theory

You should refer to papers for the complexity analysis. See for example http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.219.4060&rep=rep1&type=pdf

[Muhammad Ali Qadar]

This paper also dont give any idea how to find the complexity its just telling that this is complexity of approach he is using. if Its a topic of interest why there is no ... consideration of it on internet .. I am searching but can not find any concrete material or example.

[Walter Roberson]

One source: http://dl.acm.org/citation.cfm?id=1412710

See also any of the foundational books by Aho and Ullman, including http://infolab.stanford.edu/~ullman/focs/ch03.pdf

Answer 3

[Sean]

I too am interested in calculating the computational complexity of a sequence of code executed in Matlab as I wish to do protyping in Matlab and then transfer it to embedded.

Ideally, the number of floating point operations or mathematical operations would be helpful.

Does Matlab have a feature such as this?

S

[Walter Roberson]

No, it is not possible to calculate in general.

There are some quite simple code sequences that no-one has been able to find the computational complexity of despite many many people trying. See for example the Colatz Conjecture.