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Subject: Re: fast normalization

Author: Sune Fischer

Date: 08:45:56 10/31/03

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On October 31, 2003 at 09:04:41, Charles Roberson wrote:

>
>   I have a list of numbers that I wanted to normalize to the range of 0-100.
>   The numbers are integers so the obvious thought is
>      find largest
>      foreach number
>         number = number*100/largest
>
>    However, division is slow. So, I dropped the range to 0-64 and
>     came up with the following:
>         find largest
>         n = 7;
>         if largest > 64
>            n = highorder bit position (largest) + 1;
>         foreach number
>             number = number>>n
>
>     In some cases the range will be 0-32 but that is ok.
>     Seems this should be fast and I haven't thought of anything faster.

If possible, try and design around it.
Such heavy math shouldn't be needed in a chess program IMO, simpler schemes will
often be 10 times faster and 95% as good.

Maybe there is some way you can generate the numbers to fall in the right range
directly (if the numbers are computed from tables, maybe try changing the tables
etc..)?

-S.



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