Author: Ratko V Tomic
Date: 09:23:00 10/18/99
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> I don't think the 'difference' matters... The display showed total time for all iterations, and although the last one is always the largest, to get time/iter one needs to subtract adjacent totals to get time per iteration, before finding the ratios of the latter. > whether you count nodes, or > you use time per iteration, it really doesn't matter... but the time > per iteration is _far_ better... The time is an approximate and a very rough substitute for node count, since it is, at best, a sum of several different exponential terms and polynomials (in nominal depth or iteration number). Whether it is better than node count, depends what are you measuring it for. If you are interested in estimating time for some deeper iterations, then yes, time is better. But for other purposes node counts may be more interesting number. > because your node count method is > dead wrong. it is assuming that "d" is a constant. It is not. > D is very dynamic in crafty, particularly beyond the opening. The concept of effective branching factor (EBF) is already an artificial construct since the actual branching factor varies from node to node anyway. The whole idea behind it is to get a simpler tree (of fixed depth and width) as a managable substitute for the real search tree in order to do some calculations on the simpler model. With the real search tree one could only measure (count) various parameters during execution. With the simplifed one we can get rough estimates woithout measuring. Of course, we're all well aware of the limitations of such simplifed model (built into EBF concept), and that's why I suggested 2 alternative methods to measure/sample the actual proportion of "junk" evaluations/visits and find whether the proportion of "non-junk" drops exponentially to 0 with the increase in the (nominal) search depth.
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