Is this the entire code you've written or is it pseudocode? It doesn't seem to be indexed by point nor are you looping.
It also doesn't seem to do what you want:
if dis<maxdis
ra=2*rand;
newp= x*ra
This says that if the distance of the point from the centre is less than the maximum distance, you sample a random number in [0,2] the multiply the point by the random number. If rand > 1 this will move points away from the center.
else
% push the point towards the centre
step=0.5;
newp= x+step;
end
This also does not move the points towards the centre. It says if the point is the furthest from the center, move it 0.5 units away in each direction.
I think you need to rework your algorithm, or post what you're actually doing.
