randperm(n,k) in R2011a

I try to port some new (R2015b) code using randperm(n,k) back to pre-R2011a. And initially i thought i could use r = randperm(10); r(1:4); as replacement for randperm(10,4) but then

>> rng(11313)

>> randperm(10,10)

ans =

    10     1     7     8     5     6     3     9     4     2

>> rng(11313)

>> randperm(10)

ans =

     9     1    10     6     7     3     8     2     5     4

i cannot see a structure, how randperm operates.

Answer 1

[Thorsten]

We cannot have a look into the randperm function. So if it is essential for you program to produce the same sequence of random numbers, you have to use

r = randperm(10); r(1:4);

in your program, also in the R2015b version.