[Push] Success with ODD

[Rud Merriam]

Finally, had a success with ODD.

First, I dropped back to trying a different problem: multiply the top of the
integer stack by 1 less than the top (X * X-1). This was a starting point
for solving for factorial. Found problems in various places and made the
fixes. I got this problem to work with various combinations of parameters.

So just now tried ODD and after 94 generations arrived at:

(CODE.= INTEGER.%)  4 INTEGER.% BOOLEAN.FROMFLOAT  EXEC.STACKDEPTH ( (
CODE.= INTEGER.%  CODE.CDR CODE.=)  FLOAT.=) BOOLEAN.FROMINTEGER

Which simplifies to: EXEC.STACKDEPTH (INTEGER.%) BOOLEAN.FROMINTEGER

The solution gets cute by using the exec stackdepth to push 2 on the stack
which is used for the integer modulus to produce a 1 or 0, which is then
converted to the boolean. 

Parameters (that I'm controlling right now) were:

EVALPUSH-LIMIT=50
MAX-POINTS-IN-RANDOM-EXPRESSIONS=15
MIN-POINTS-IN-RANDOM-EXPRESSIONS=5
RANDOM-SEED=52432

max_programs=1000
tourney_size=4
generations=150
crossover=80
mutation=15
duplicate=5

Fitness test was 50 for not stopping, 100 for no boolean value, 10 for wrong
test result, and 5 for each time the current and previous boolean value were
the same (penalty for constant values). 
----

I'm surprised at the sensitivity of parameters in getting solutions. For
example, changing tournament size from 2 to 3 or 4 might result in no
solution when a solution had been found, or the reverse. Or changing the
random seed can change from getting a solution to not. 
 
 - 73 - 
Rud Merriam K5RUD 
http://mysticlakesoftware.com/

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