# key/value array of known size
define(_size,0)
 define(_val,-1*$1)
define(_key,$1)

# iterator for storing n samples from a distribution in a working memory (wme)
define(InitVars,`wme,n,     nums,i')
define(init1,`
    delete nums;
    for(i=1;i<=n;i++)  
    	nums[i] = $2 + (rand()*Tiny); 
	nums2cdf(nums,wme,n,$1)')



##########################################################################

BEGIN {Tiny=10^(-10);
	   Small=Tiny*10
   }
function nums2cdf(nums,cdf,n,key,    min,max,i,j,one,sum,before)	{
	min= 10^32; 
	max= -1 * max;	
	# find min, max		
	for(i=1;i<=n;i++) { 
		one = nums[i]
		max = one > max ? one : max;
		min = one < min ? one : min; 
	}	
    # sum the curve
	for(i=1;i<=n;i++) {
		one = (nums[i] - min)/ (max - min);
		sum += one;		
	}
	# generate cdf
	before=0
	asort(nums); # sorts min to max, so we'll run it backwards
	for(i=n;i>=1;i--) {
		j                 = n - i + 1;				
		cdf[key,_val(j)]   = int(nums[i]/Small) *Small;
		cdf[key,_key(j)]   = 1 - before; # store cdf at i
		one               = ((nums[i] - min)/ (max - min))/sum;
		before += one
	}
	cdf[key, _size] = n
}
function pick(w,key,   i,want,left,right,mid,most,min,max) {
	# bin chop
	most = w[key,_size];
	want = rand(); 
	left = 1;
	right= most;
	while(left < right) {
		mid = int((left+right)/2);
		want < w[key,mid] ? left = mid+1 : right=mid
	}
	if (left==1) {min=1; max=2} else {min=left-1; max=left};
	min = w[key, _val(min)]
    max = w[key, _val(max)]
    return between(min,max)
}
 
function round(x)         { return int( x + ((x < 0) ? -0.5 : 0.5)) }
function between(min,max) { return (max < min) ? between(max,min) : min+ ((max-min)*rand())}
function ratio(min,max)   { return between(min,max) }
function nominal(range)   { return ordinal(range) }
function ordinal(range)   { return range[ratioInt(1,range[0])] }
function normalInt(m,s)   { return int(normal(m,s)) }
function normal(m,s)      { return m+box_muller()*s }
 
 function ratioInt(min,max,   aLittle) {
   if(min==max)
     return min;
   aLittle = 0.499999;
   min=min - aLittle;
   max=max + aLittle;
   return round(between(min,max));
 }
 
 function box_muller(m,s,    n,x1,x2,w) {
   w=1;
   while (w >= 1) {
     x1= 2.0 * rand() - 1;
     x2= 2.0 * rand() - 1;
     w = x1*x1 + x2*x2};
   w = sqrt((-2.0 * log(w))/w);
   return x1 * w;
 }
 
 function indexOf(x,range,i) {
   for(i in range) 
     if (i > 0 )  
       if (range[i]==x) 
          return i;
   bad(x " not in range \n");
 }

BEGIN {
	srand(Seed ? Seed : 1)}

function inits(InitVars) {
	init1("age",   normalInt(100,10) )
	init1("weight",normal(10,1)  )
}