Re: Equivalent of colon operator to increment a vector

"James Tursa" wrote in message <koo6hp$m33$1@newscl01ah.mathworks.com>...
> "Alexandru" wrote in message <koo5t6$jur$1@newscl01ah.mathworks.com>...
> > "Alexandru" wrote in message <koo58k$hsd$1@newscl01ah.mathworks.com>...
> > > Hello,
> > >
> > > I know one can do 1:5 to generate the vector with entries 1 2 3 4 5.
> > > Suppose I want to do the same but starting from a vector, i.e. do [1; 2; 3] : [5; 6; 7] to get a 3 by 5 matrix:
> > >
> > > 1 2 3 4 5
> > > 2 3 4 5 6
> > > 3 4 5 6 7
> > >
> > > This doesn't work in Matlab as I only get the first line. I know I could do a for loop etc, but is there a direct way of doing this (avoiding loops)?
> > >
> > > Thanks,
> > > Alex
> >
> > I know that I can simply do [1:5; 2:6; 3:7] but that's not what I want. The starting vector will be the output of previous code. Its elements will not be consecutive and its size is not fixed.
>
> It is not clear to me if you have two vectors that you are working with, or just a desired length for the output. In any event, here is one way to do it:
>
> >> a = [1;3;7] % not consecutive
> a =
> 1
> 3
> 7
> >> b = a + 4
> b =
> 5
> 7
> 11
> >> n = b(1)-a(1) % dynamically calculated length
> n =
> 4
> >> bsxfun(@plus,a,0:n)
> ans =
> 1 2 3 4 5
> 3 4 5 6 7
> 7 8 9 10 11
>
> James Tursa

Thanks James!