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AI Game Programming Wisdom
Approximately 70 articles by Artificial Intelligence programmers discuss the skills and concepts needed to apply AI to game development.
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pointers needed

Hey,

well i'm gonna do the project this autumn semester that is already in progress.

I've read some tutorials on NNs and GA and also your tutorial on Obstacle Avoidance using NNs a couple of times. Here's what i understand of it and questions that i have.

The inputs are the movement simulation of the bot in different direction. I suppose that if for example you had 3 sensors, one of them would be straight in front and the other 2 on the sides at a certain angle and symmetrical to the centre one. The output is the change in direction of the bot, considering that it's always moving at a constant speed. The weights and activation function are in a way that makes the output turn in the correct direction depending on which direction had the furthest distance. For example, the weight of the left sensor could be negative and right sensor positive. The activation function would make the output be a left turn if the input if negative. Is this correct or am i completely off-track ? That would imply that we're asking the bot to point in the direction with the furthest distance but you said in your tutorial that we would let the bot have the freedom of learning the best possible approach, that's why i think i may not have got it right.

Now about learning, i suppose here that making the bot learn is by changing the weights in the NN. By using GA to do this, we can have unsupervised learning because it will be done by the GA. Does this mean that i could manually change the weights and do some supervised learning if i'm not using GA ? I have an AI class with the first lab being with GA so i might be more familiar with it by the end of the month, but is the GA something i could not use if i see that the project is too much ? I'm asking just in case.

As you can see, things are not all that clear and that's why i'm don't know too much about the amount of work i have to do to have something working. This is my last semester in comp. eng. and i have 4 courses left (not the usual 5) so i can be pretty focused on the project. What i need right now, is just some pointers so that i don't go off to a bad direction. I think it's a do-able project because the NN class itself won't take much time (hopefully) and the interaction with quake 2 with FEAR won't be as difficult as doing it from scratch so i think i can mainly focus on using the NN and understanding it.

thanks

9 posts.
Tuesday 10 September, 12:12
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answer to my own question

Ok, after some research, i think i have some answers to some of these questions.

For the weights, I will not have to worry about their values because they will be random at the start and "evolve" with the GA. I think that's what you meant by saying to not impose the bot's behaviour but to let it learn by itself the best approach, which will be largely dependant on the fitness function.

Is this is not correct, please tell me ;-)

Anyways, i'm gonna go check out FEAR and play with it now.

9 posts.
Monday 16 September, 01:53
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