how to move points by steps to the centre and how to change the direction

Dear,

I have these points and a point call centre. I want to accumulate the points around the centre.

x=[  24.5270   27.5315
 29.9260   26.9389
 23.9923   21.3688
 20.6191   29.0696
 22.9296   23.7888
 25.5227   25.2962
 27.4013   29.8862
 23.1840   29.5821
 24.9386   28.1765
 26.2867   24.2390];
the centre=[ 31.5618   27.1874];
the distance between the points and the centre

dis=[ 7.0433,1.6546,9.5474,11.1034, 9.2771, 6.3283,4.9592,8.7133,6.6967,6.0432]';

I took the half maximum distance and compared others with it if the distance of the point larger then move it to the centre using a step, if not the just move it in small direction around the centre. I wrote this code but it doesn't help, it push some points far from the centre, see the code

%let x=one point
  dis;
  maxdis=max(dis);
  maxdis=maxdis/2;
% for each point separately 
  % just move the point around the centre a little
  if dis<maxdis
      ra=2*rand;
     newp= x*ra
  else
% push the point towards the centre
      step=0.5;
     newp= x+step;
   end

in fact I don't know how to direct the points to the centre, I may have the points in any place around the centre so how I'm going to deal with them.

I appreciate any help

Nadia,

[jgg]

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.

[nadia nadi]

Dear, thanks I manage to write it correctly.

many thanks.