[Jprogramming] Fwd: Re: extended precision essay

['Mike Day' via Programming]

As may be seen,  Roger Hui felt unable to advise re my private enquiry 
on one of his essays
in the J Wiki.  Anyone else feel like commenting on the apparently 
unproductive lines of
code?
Thanks,
Mike


-------- Forwarded Message --------
Subject: 	Re: extended precision essay
Date: 	Wed, 24 Apr 2019 19:00:47 -0700
From: 	Roger Hui <rogerhui.canada at gmail.com>
To: 	Mike Day <mike_liz.day at tiscali.co.uk>



Hi Mike.  Thanks for you msg. I am heavily engaged in other matters now, 
so if you want to have a more timely answer I suggest you query 
programming at jsoftware.com <mailto:programming at jsoftware.com>.



On Tue, Apr 23, 2019 at 6:58 AM Mike Day <mike_liz.day at tiscali.co.uk 
<mailto:mike_liz.day at tiscali.co.uk>> wrote:

    Dear Roger,

    I've been trying to use material from your Essay on extended precision
    functions at

    https://code.jsoftware.com/wiki/Essays/Extended_Precision_Functions#Utilities

    and am puzzled by apparently unproductive code in the hyperbolic
    functions,

    eg

    sinh=: DP&$: : (4 : 0) " 0
       if. x>10^.|y do. (1r2*_1^0>y)*x exp |y end.
       if. 1<|y do. -:-/x exp y,-y end.
       e=. 0.1^x
       n=. e (>i.1:) y (^%!@]) 1+2*i.>.0.5*y^.e
       +/(x:!.0 y) (^%!@]) 1+2x*i.n
    )

    I would expect the if statements either

         to modify or produce values for use later in the function

    or

        to have a "return." before the "end."

    Not at all important,  but I'd welcome your ideas when you have time.


    Very sad about John Scholes.  I'd guess you enjoyed your collaboration
    at Dyalog,

    Best Wishes

    Mike



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