1	TOP      = 10
     2	MaxLIVES = 5
     3	LIVES    = MaxLIVES
     4	SAMPLES  = 20
     5	
     6	which2() 
     7		counts()
     8		for class1 in classes do
     9			which = round0(class1)
    10			which = rounds(class1, which)
    11			print "rules for class1 are " which
    12	
    13	counts() 
    14		for row in rows do
    15			NUMBER[class of row]++
    16			NUMBER["all"]++
    17			for col in row
    18				FREQUENCY[class of row, col, value of col]++
    19				FREQUENCY["all",        col, value of col]++
    20	
    21	round0(class1) {
    22		for (class2,col,value) in FREQUENCY do
    23			if (class1 == class2)
    24				best0 = FREQUENCY[class2,col,value]  
    25				bests = NUMBER[class2]
    26				rest0 = FREQUENCY["all", col,value] - best0
    27				rests = NUMBER["all"] - bests
    28				best  = best0/bests
    29				rest  = rest0/rests
    30				if (best > rest)
    31					push (best^2/(best + rest), col,value) onto SCORE 
    32		return TOP items of SCORE
    33	
    34	rounds(class1,which0) 
    35		if   no improvement from last round 
    36		 	then LIVES--
    37			else LIVES=MaxLIVES
    38		if LIVES < 1
    39			then return which
    40		sample = explode(normalize(which0))
    41		which1 = copy(which0)
    42		SAMPLES times repeat             ; e.g 20 times repeat
    43			one = any item from sample
    44			two = any item from sample
    45			new = combine one and two
    46			push (abcd(new,class1), new) onto which1
    47		which2 = TOP items of which1
    48		return rounds(class1,which2)
    49	
    50	normalize(list) 
    51		for key in list do total =+ array[key]
    52		for key in list do list[key] = round (100*list[key]/total)
    53		return list
    54	
    55	explode(list) { ; e.g. a[apples]=90, a[bananas]=10
    56		for key in list
    57			for i = 1 to list[key]
    58				push key onto out
    59		return out   ; e.g. contains 90 apples and 10 bananas
    60	
    61	abcd(class1, rule) 
    62		for row in   rows  
    63			triggered = rule matches row
    64			if (class of row == class1) {
    65				{if triggered then d++ else b++ }
    66			} else {
    67				{if triggered then c++ else a++ }
    68			}
    69		probability of detection = pd = d/(d+b)
    70		probability of false alarm = pf =c/(c+a)
    71		precision = prec =d/(d+c)
    72		accuracy = acc = (a+d)/(a+b+c+d)
    73		support = s = (c+d)/(a+b+c+d)
    74		fmeasure = 2*pd*prec/(pd+prec)
    75		return support * fmeasure

========================================================
;class,thing=value,thing=value

111111111111111
start with some scored sorted things

32,no,temp=humid
22,no,windy=true
12,no,forecast=raininng

222222222222222
A couple of times, pick two things at random,
favoring the higher scored things

1)
no,temp=humid
no,temp=humid

2) 
no,temp=humnd
no,windy=true

3) 
no,windy=true
no,forecast=raining

333333333333333 combine and score

1) 32,no,temp=humid
2) 20,no,temp=humnd,windy=true
3) 5, no,windy=true,forecast=raining

444444444444444 sort into the stack (ignore if already there)

32,no,temp=humid
22,no,windy=true
20,no,temp=humnd,windy=true
12,no,forecast=raininng
5, no,windy=true,forecast=raining

555555555555 prune all but the top (say) 3 things

32,no,temp=humid
22,no,windy=true
20,no,temp=humid,windy=true

6666666666 goto 1