Re: [Bug-gnubg] Neural network symmetry question

[Joseph Heled]

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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