[Melbourne-pm] Timer::HiRes and alarms? (Was: AI Contest)

[Toby Corkindale]

On 11/11/10 17:21, Nathan Bailey wrote:
> I'm using the MyBot.pl from your git repository, which has:
> local $| = 1;
> at the top, so I presume that would make it autoflush, so the alarm
> could print.

The "local $| = 1;" was inherited from the original Perl starter 
package, which is of dubious quality; it might be better to make it "$| 
= 1;" instead. ie. Global, not local.. In case the alarm signal handler 
is occurring inside a different scope?
(That's clutching at straws, but worth a shot..)


> I gave up on trying to work out the SIG ALRM stuff. I don't think I've
> ever had a genuine timeout. The only times I see timeouts are:
> 1. Bad code (the engine doesn't like "stderr", despite the docs, so if I
> forget to tag a 'warn', it often fails; otherwise general crashes and bugs)
> 2. When I've had while loop where the exit condition wasn't reached
> (programmer error :-)

Likewise, I've found my code always has plenty of time to spare, apart 
from poor coding.. but then, my bot isn't that complicated either.
(He just runs through three phases - 1) global analysis; 2) per-planet 
defensive analysis; 3) per-planet further analysis and moves.
It's more like an interconnected heuristic system, rather than proper 
AI. Although I *want* to make it have more I and less A than it does 
currently.. when time allows :/ )

> I have written a simple engine that lets me trap most of my errors
> (although it doesn't reproduce the results of the java engine so
> presumably it has bugs too :-)
> I'm happy to share (eg. publish it in your git repository) it if no-one
> laughs at my code ;-) [ especially if people can fix its bugs! ]

Hmm, there's already source for the C and Java implementations of the 
engines. If you're worried about your implementation, maybe it would be 
better to just modify one of the stable engines to allow for more debug 
output?


> When I started, I wasn't sure if I just submitted 'MyBot.pl' or all the
> .pms too, so I avoided putting code into modules and undid my initial
> changes to PlanetWars.pm
> I think PlanetWars.pm could be way more efficient and could have a
> number of other helper functions (eg. ClosestPlanet() would be an
> obvious one)

Yeah, it could definitely do with some improvements.
My Git repo holds a few by now, but only so far as improving the 
existing methods.
I've added various things (privately) such as locating nearby planets, 
summing fleet-effects and predicted planet populations, but kept them 
private. The published code is meant to just be a starter package, after 
all.
.. plus my code isn't very good yet, anyway.


> Unfortunately I seem to be able to generate bugs that can't be
> reproduced with either the local java engine or my simple Perl engine,
> and are sometimes hard to even debug on the tcp server. At the moment, I
> issue some orders and finish the turn and end up in an endless loop of
> undefined input (ie. ' next unless defined($current_line); ') which is
> pretty hard to debug, beyond simply truncating my code to find a
> codebase that it doesn't happen to. Even if I send 'go' I still don't
> get any input back, and I never get the final 'you timed out, you lose'
> messages either.

That does sound odd; something must be quite broken if it's failing at 
that basic level of I/O! Can you write a simple test harness to operate 
on the methods parsing the game-state only?