Re: LOGO-L> Factorials

[George Mills <mills@softronix.com>]

Changing to FOR may be a tad slower than REPEAT but the bulk of
the time is now simply fetching the correct precalculated value from
the "factorial cache".

If things were real large and less predicatable you can also Fill
the "cache" on demand. You do this by "tagging" each entry as to
its validity.

Since now you won't be needing the P266 I'll give you an address
you can forward it to :-).

Yehuda Katz wrote:
> 
> Hello George,
> 
> Thank for your nice tip. It can serve as a nice introduction to the
> subject of arrays in Logo, and I'm going really to use it.
> 
> I modified your program a little bit, probably at the cost of some
> slower performance, by trading REPEAT with FOR (in compute_facts).
> 
> =======================================
> to do
> compute_facts
> for[num 100 999][
>    if equalp :num(sum fact item 1 :num
>                       fact item 2 :num
>                       fact item 3 :num)
>    [pr :num]]
> end
> 
> to compute_facts
> make "factarr(array 10 0)
> for[i 0 9][
>       setitem :i :factarr fact_real :i]
> end
> 
> to fact :n
> op item :n :factarr
> end
> 
> to fact_real :n
> op ifelse :n<2[1][:n*fact_real :n-1]
> end
> =======================================
> 
> Regards...
> 
> [[Yehuda]]
> 
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-- 
===============================================================
George Mills
email: mills@softronix.com
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