Quicksort MATLAB

Implementation of standard quicksort Algorithm in MATLAB.

Description

It uses recursion to to implement quicksort. For the purpose of partitioning pivot is chosen according to median-of-three scheme.

• MATLAB release: MATLAB 7.7 (R2008b)

[James Tursa]

There is absolutely NO help with this submission. No H1 line, and absolutely 0 comments in the code. So you have to edit the code to figure out how to run it, and make guesses as to the desired inputs based on the variable names used. So I made some guesses and here is a quick (pun intended) example:

>> a = rand(1,100000);
>> tic;b=sort(a);toc
Elapsed time is 0.011785 seconds.
>> tic;[c,CPU_cost]=quicksort(a,1,100000,0);toc
Elapsed time is 113.274774 seconds.
>> isequal(b,c)
ans =
     1

So this modest sized data set ran almost 10,000 times slower than MATLAB's built-in sort function. For a large data set I can only imagine it would take hours or days to complete. So this is not a useful function for any practical use. It *might* serve as a simple algorithm example for someone, but even that is severely diminished by the fact that there is not one line of comments in the entire code package ... not one. I give it a 2 star rating instead of a 1 star rating only because it did produce the same result as MATLAB ... at least for my one spot check.