int pnts[] = primpoints(0, @primnum);
int num = len(pnts);
int i;
float inc = 1.0/(num-1);
for(i=0; i<num; i++){
    float pscale = fit01(chramp('pscale', inc*i), chf('pscale_min'), chf('pscale_max'))*chf('pscale_mult');
    setpointattrib(0, 'pscale', pnts[i], pscale);
}