Re: exercise in double number arithmetic

On 7/7/24 00:48, Ahmed wrote:

On Sat, 6 Jul 2024 23:50:28 (UTC), Krishna Myneni wrote:
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On 7/6/24 16:59, Ahmed wrote:

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: solution ( -- d)
     1 s>d 43 22 do i 1 m*/ loop d>f
     21 dup s>d rot 2 do I 1 m*/ loop d>f
     f/ fround f>d ;
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...

Krishna

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You have not to use fround. (42!/21!) is an integer and is multiple of
21!.
in other words 42! is multiple of (21!)^2.
>

 The FROUND is necessary because 42!/21! is too large of an integer to be exactly represented by double-precision fp (IEEE format) and F>D is a truncating operation, not rounding.
 The whole D>F and floating point operations can be dispensed with if we have D/MOD -- a double length version /MOD.
 -- Krishna