Numerical error using the "diff" function

Question

Michael Loibl 2021-2-22

回答： Stephen23 2021-2-22

I want to determine the max difference between adjacent entries of a vector.

vector = [0 0 0 0.2 0.4 0.6 0.7 0.85 1 1 1];
difference = diff(vector);
i=find(diff(vector) == max(diff(vector)))

For the exemplary vector I would expect the following output:

i =
     3     4    5
     

However, I get:

i =
     3     4
     

The third one is missing. Checking this value, indeed I see some numerical error which should not be there.

Do I really have to use an almost equal function in order to solve this issue?

Answer 1

Stephen23 2021-2-22

V = [0,0,0,0.2,0.4,0.6,0.7,0.85,1,1,1];
D = diff(V);
X = find(ismembertol(D,max(D)))
X = 1×3
     3     4     5