subtracting consecutive elements from arrays

I have 2 arrays. To generate e, I want to subtract d from Q. After the first 10 times, I want to cycle back through Q for the next 10 times.

The result should be: e = [9 14 22 21 11 9 3 4 -1 3 9 14 23 21 13 9 3 -1 -1];

num = [50 51 53 51 50 55 56 57 53 54 55 56 58 55 54 57 58 59 60 61];
Q = [10 15.8 19.5 19.5 15.8 10 4.1 0.5 0.5 4.1];
d = diff(num); 
e = round(Q - d);

Answer 1

[dpb]

num = [50 51 53 51 50 55 56 57 53 54 55 56 58 55 54 57 58 59 60 61];
Q = [10 15.8 19.5 19.5 15.8 10 4.1 0.5 0.5 4.1];
d = [diff(num) nan]; 
e = round([Q Q] - d);
e=e(isfinite(e))

e = 1×19

9 14 22 21 11 9 3 5 -1 3 9 14 23 21 13 9 3 -1 -1

all(e==[9 14 22 21 11 9 3 4 -1 3 9 14 23 21 13 9 3 -1 -1])

ans = logical
   0

I believe your posted answer is off by one in the 8th postion; should be 4, not 5...

[C.G.]

thank you