Count maximum length of values < 1 in matrix

Dear all,

I am interested in determining the maximum length of values < 1 in A. E.g., the length of values < 1 in A: 1 at A(1), 10 from A(3:12), and 17 from A(15:end). The maximum length I should get is 17 from A(15:end).

A = [0 6.858 0 0 0 0 0 0 0 0 0 0.762 5.334 2.54 0 0 0 0 0 0 0 0.762 0 0 0 0 0 0 0 0 0.508]; 
rdc   = find(A > 1);        % Returns the index of value > 1
CDD_m = max(diff(rdc))-1;   % Calculates the backward difference in rdc. The maximum value represents the maximum length of A<1.

1. rdc gives [2 13 14] which coincides with the values [6.858 5.334 2.54].
2. CDD_m gives 10.

However, 10 is incorrect as it is not the maximum length of values < 1. Any ideas on how to solve this issue?

Thank you.

Answer 1

[Walter Roberson]

A = [0 6.858 0 0 0 0 0 0 0 0 0 0.762 5.334 2.54 0 0 0 0 0 0 0 0.762 0 0 0 0 0 0 0 0 0.508]; 
mask  = A < 1;
starts = strfind([false, mask], [0 1]);
stops = strfind([mask, false], [1 0]);
[len, idx] = max(stops-starts+1);

fprintf('longest run is %d starting from %d going to %d\n', len, starts(idx), stops(idx))

longest run is 17 starting from 15 going to 31

[Eli]

Thank you!