From: brabuhr@...
Date: 2009-07-16T11:28:00+09:00
Subject: Re: [QUIZ][SUMMARY] Genetic Programming (#212)

On Tue, Jul 14, 2009 at 11:49 PM, Daniel Moore<yahivin@gmail.com> wrote:
> And now what you've all been waiting for... the mystery function:
>
>    def mystery(x, y)
>      3 * x * y + 5 * (y**3) - 7 * x
>    end

Cool.  I was not thinking and I rebooted while my script and output
were in /tmp; the machine is set to clear tmp on boot: so, I lost my
lowest-delta functions.  But, I recovered these:

> cat foo
DATA = [[8, 16, 20808], [22, 31, 150847],  [5, 16, 20685], [12, 19, 34895],
        [18, 25, 79349], [20, 33, 181525], [31, 1, -119]  , [19, 33, 181433],
        [0, 12, 8640], [13, 12, 9017]]

# An example of one of the closer ones I found:

f = "(y) * + x - - - - + x - x - 3 * 82 / y + - 5 + + + x - y * y + y
- 2 * (x + y) / 459 + + - + - - 5 + (y) - 2 + - + 5 + (y) / + 5 - - -
+ + - + x - 3 * 8 + x - + (y) * 5 - x - - x + (y) * 5 + y * (y) / (y)
* y * (y) * 5 + y * (y) * 5 / 3 / (y) * - - + x - 3 + (y) * y / (y) *
y"
puts DATA.map{|(x, y, ev)| puts "#{x}\t#{y}\t#{ev}\t#{av =
eval(f)}\t#{delta = (ev - av).abs}";  delta}.inject{|s,v| v += s}
puts

# I think this was the second best I found; unfortunately, I did not save
# the original output.  The version here was after some hand editing while
# pasting it into a spreadsheet, e.g.:
#   "x + + + - + y" => "x - y";  "x + - + - + y" => "x + y";  "(x)" => "x"

f = "-5 * y / 4 - x - y - 5 * 8 + y / 5 * -y / 5 + 5 * y - 8 / -8 - y
/ 5 / 4 * 4 + 5 - 7 - 3 / 6 - y / 5 * -4 / y * y + 3 / 6 * -x + 4 + 5
+ 1 - 3 / 6 / -8 * y + 8 / -8 + 8 * + 1 + y / 5 * -y / 5 * -4 * 4 / +
y + 6 - y - 8 + 8 / -8 + 5 / 8 * -8 + y / 5 * 8 / -8 - y + 7 + y * x +
5 * y * y * y + 3 * -x + y + 8 / 3 / 6 - y - 8 / -8 - y / 5 * -4 + y *
y / y * x + 8 * y / -4 + 5 / 84 * 8 * -3 * 4 - x + y * x"
puts DATA.map{|(x, y, ev)| puts "#{x}\t#{y}\t#{ev}\t#{av =
eval(f)}\t#{delta = (ev - av).abs}";  delta}.inject{|s,v| v += s}
puts

# I added "- 5" to the above:

f = "-5 * y / 4 - x - y - 5 * 8 + y / 5 * -y / 5 + 5 * y - 8 / -8 - y
/ 5 / 4 * 4 + 5 - 7 - 3 / 6 - y / 5 * -4 / y * y + 3 / 6 * -x + 4 + 5
+ 1 - 3 / 6 / -8 * y + 8 / -8 + 8 * + 1 + y / 5 * -y / 5 * -4 * 4 / +
y + 6 - y - 8 + 8 / -8 + 5 / 8 * -8 + y / 5 * 8 / -8 - y + 7 + y * x +
5 * y * y * y + 3 * -x + y + 8 / 3 / 6 - y - 8 / -8 - y / 5 * -4 + y *
y / y * x + 8 * y / -4 + 5 / 84 * 8 * -3 * 4 - x + y * x - 5"
puts DATA.map{|(x, y, ev)| puts "#{x}\t#{y}\t#{ev}\t#{av =
eval(f)}\t#{delta = (ev - av).abs}";  delta}.inject{|s,v| v += s}
puts

> ruby foo
8	16	20808	20816	8
22	31	150847	150842	5
5	16	20685	20681	4
12	19	34895	34916	21
18	25	79349	79369	20
20	33	181525	181526	1
31	1	-119	-128	9
19	33	181433	181435	2
0	12	8640	8602	38
13	12	9017	9057	40
148

8	16	20808	20810	2
22	31	150847	150859	12
5	16	20685	20681	4
12	19	34895	34902	7
18	25	79349	79361	12
20	33	181525	181530	5
31	1	-119	-78	41
19	33	181433	181436	3
0	12	8640	8625	15
13	12	9017	9028	11
112

8	16	20808	20805	3
22	31	150847	150854	7
5	16	20685	20676	9
12	19	34895	34897	2
18	25	79349	79356	7
20	33	181525	181525	0
31	1	-119	-83	36
19	33	181433	181431	2
0	12	8640	8620	20
13	12	9017	9023	6
92