Author: Tom Kerrigan
Date: 21:14:05 04/23/00
Go up one level in this thread
On April 23, 2000 at 23:40:32, Robert Hyatt wrote:
>On April 23, 2000 at 22:44:53, Tom Kerrigan wrote:
>
>>On April 23, 2000 at 22:28:59, Flemming Rodler wrote:
>>
>>>On April 23, 2000 at 20:00:27, Tom Kerrigan wrote:
>>>
>>>>On April 23, 2000 at 19:35:06, John Coffey wrote:
>>>>
>>>>>I assume that at least some programs generate a complete move list at every
>>>>>branch of the tree. That is my intent at the moment. (My 1987 program was
>>>>>kind of dumb in that it only cared about move order at the base of the tree, so
>>>>>it always generated moves on the fly above the base without keeping a list.)
>>>>>
>>>>>So I see myself having a big array of moves. When I generate moves deeper than
>>>>>the base, I will add them to the array and keep track of where the beginning and
>>>>>end are for the current depth.
>>>>>
>>>>>Does anyone else do it this way? Is this a valid approach?
>>>>>
>>>>>John Coffey
>>>>
>>>>Yes, it's extremely valid. Here's what I do:
>>>>
>>>>move_t move_heap[];
>>>>int first_move[], last_move[];
>>>>
>>>>So to loop through all the moves for a given ply, this is what I do:
>>>>
>>>>for (i = first_move[ply]; i < last_move[ply]; ++i) {
>>>> // the move to examine is move_heap[i]
>>>>}
>>>>
>>>>-Tom
>>>
>>>Since you have that first_move[ply] = last_move[ply-1]+1 you don't need
>>>first_move[]. Maybe it will even save you some time since you do not avoid a
>>>lookup in first_move.
>>>
>>>/Flemming
>>
>>Having first_move is nice because you can't access last_move[-1] (for ply 0). Of
>>course, you can avoid this problem if you're careful, but for now I'm taking the
>>straightforward approach.
>>
>>-Tom
>
>
>This isn't a problem if you start with ply=1 and not 0.
I have several data structures that use ply as an index, so starting at ply=1
would be an annoying waste of memory. Probably minor, but it would still annoy
me. What I was thinking, though, is only keeping the first_move[] array instead
of only last_move[]. Then the loop can look like:
for (i = first_move[ply]; i < first_move[ply + 1]; ++i)
...
-Tom
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