Modal

Calculates statistical mode and returns indices

Description

Calculates the statistical mode (the most frequently occurring element) in a vector (or matrix), and returns the mode, the number of occurrences and the indices of the mode in the vector. Like the build in mode, only also includes indices.
Reasonable fast :-)
If more than one mode exist (2+ elements with equal maximum occurances) first one found is returned.

Plz comment or leave feedback

• MATLAB release: MATLAB 7.3 (R2006b)

[Felix Hebeler]

Just to make this clear: the build in 'mode' command does the trick in Matlab, this function only also works for 2&3D matrices and also returns the indices of the modal elements. If there are more than one element with equal number of occurrances, the first one found will be returned.

[Scott Miller]

Felix

[m,in] = mode(A(:));

works for N dimensional matrices and with NaN, although the one-liner is much slower (there is a lot of general error checking overhead in mode) and doesn't return the number of hits. It also returns the first element found in index form, not subscript form.

If you use the A(:) trick in your code rather than reshape, modal runs 30% faster.

Scott

[Felix Hebeler]

True, took this out of a script and didn't think about it. Thanks for the feedback, I kicked the reshape part out. It's even more than 30% faster in some cases now..

[Jan Churan]

 

[Jan Churan]

 

[Jan Churan]

Beware, the function imho gives wrong results. It can be "fixed" by replacing 'sum' by 'length' in line 18 and '[]' by 'NaN' in line 24