nconsecutive

NCONSEC = NCONSECUTIVE(X) returns a vector containing the maximum number of consecutive integers in each row of matrix x.

Note that while this code is not vectorized, it was tested against two different vectorized versions; the for-loop code ran about twice as fast as the vectorized versions.

Example:
nconsec = nconsecutive([1 2 3 5 6 7; 8 7 6 2 4 1; 2:7; 9:-1:5 5])

Editor's Note: You might want to try vectorizing this to work along the columns instead of along the rows; since MATLAB is column major this may be more effective.