Create intermediate indices from vectors of start and stop indices?

Is there a fast way to create a vector of indices taking as an input two vectors containing the start and stop indices?

I want:

a = [2 7 9 17]; b = [4 7 12 17];
c = fun(a,b) = [2 3 4 7 9 10 11 12 17];

[Image Analyst]

I guess I'm not following. Which of the 4 elements of a, or the 4 elements of b, or the 9 elements of c represent the start indices, and which represent the stop indices?

Answer 1

[Jan]

See Bruno's FEX: mcolon.

Are the values always integers? Can the intervals overlap? These details are very important for the implementation.

[EDITED] If the intervals do not touch eachother - in other words: if there is always an element between them:

a      = [2 7 9 17];
b      = [4 7 12 17];
k(b+1) = -1;
k(a)   = 1;
c      = find(cumsum(k));

For large arrays it would help to save time, if CUMSUM handle INT8 vectors - unfortunately it doesn't.

[Donald]

The values are always integers and cannot overlap, although an interval can be one element.

[Jan]

Can the intervals "touch" eachother. e.g. [1 4] [3 6]?

[Donald]

The intervals cannot touch each other so your answer is pretty much what I'm looking for.