Author: José Carlos
Date: 04:48:11 09/15/02
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On September 15, 2002 at 07:44:18, Dave Gomboc wrote: >On September 15, 2002 at 04:27:44, martin fierz wrote: > >>i wish i knew :-) >>i've forgotten what exactly i did in my 2-table code. i think i kept my >>"important table" relatively empty, and probed "forever" until i found a place >>to store the entry. "forever" was usually once, but on occasion more. >>i never quite figured out why this turned out to be less efficient than a single >>table. it's well possible that my implementation was bad... the other thing i >>thought about was that in checkers, you often have a situation where you can >>reach the same position with variable depth - happens in any endgame with kings. >>now, i was relying on the depth from root to select the table i was probing in. >>if a position stored in the "important" table turned up deeper in the search, it >>might not have been found because it was looked up in the wrong table. the whole >>thing with two tables seemed more complicated than with one, so i threw it out - >>besides, the difference is probably really small, even with a better >>implementation. >> >>aloha >> martin > >It seems to me that other things being equal (e.g. you use them in the same >way), one table with two slots is going to be slightly more efficient -- or at >least certainly not less efficient -- than two tables with one slot, due to >better prefetching and caching behaviour. > >Dave Except for the fact that you're forced to two equal size tables, whereas with two separate tables you can choose a bigger one for always replace, which seems to work better as a.r. is mainly useful near the leaves. José C.
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