Re: [Bug-gnubg] Neural network symmetry question

[Mark Higgins]

Thx - I'll run it longer and with more hidden nodes and see what happens. 



On Dec 11, 2011, at 5:44 PM, Joseph Heled <address@hidden> wrote:

> My experience tells me that 100,000 trials may not be sufficient.
> 
> With today's computing power  it should be easy to do at least a
> couple of millions.
> 
> -Joseph
> 
> On 12 December 2011 11:22, Mark Higgins <address@hidden> wrote:
>> I tried a little experiment on this: a 10-hidden-node network with a single 
>> probability-of-win output, but two setups. The first doesn't have a "whose 
>> turn is it" input and doesn't add any symmetry constraints. The second has 
>> the extra inputs for the turn and makes the symmetry constraint I described.
>> 
>> I trained them in parallel and benchmarked them against pub eval and against 
>> each other.
>> 
>> The symmetric case performed a little better: it trained more quickly, did 
>> better against pub eval, and was on par or a little better than the other 
>> case when playing head to head.
>> 
>> Details and data here:
>> 
>> http://compgammon.blogspot.com/2011/12/testing-value-of-symmetry-constraint.html
>> 
>> Of course not conclusive with such a simple setup, but kind of suggestive 
>> anyways.
>> 
>> 
>> 
>> 
>> On Dec 10, 2011, at 2:22 PM, Mark Higgins wrote:
>> 
>>> Thx! Makes sense. Though I wonder if adding back in the "whose move is it" 
>>> input and reducing the hidden->output weights by half ends up as a net 
>>> benefit for training. Maybe I'll test it out.
>>> 
>>> 
>>> 
>>> On Dec 10, 2011, at 2:06 PM, Frank Berger <address@hidden> wrote:
>>> 
>>>> Hi Mark,
>>>> 
>>>>> If I take a given board and translate the position into the inputs and 
>>>>> then evaluate the network, it gives me a probability of win. If I then 
>>>>> flip the board's perspective (ie white vs black) and do the same, I get 
>>>>> another probability of win. Those two probabilities should sum to 1, 
>>>>> since one or the other player must win (or equivalently, the probability 
>>>>> of white winning = probability of black losing = 1 - probability of black 
>>>>> winning).
>>>> 
>>>> 
>>>> I assume your assumption is wrong. IIRC in an earlier paper there was an 
>>>> input to indicate who's on. It is much simpler to present the position 
>>>> from the point of the moving player, because the net has to learn less. 
>>>> I'm not that familiar with the gnubg code, but I think they do it in this 
>>>> way, so you can't just turn the perspective.
>>>> 
>>>> ciao
>>>> Frank
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>> 
>> 
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