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Re: [Groff] Mission statement

 From: Ted Harding Subject: Re: [Groff] Mission statement Date: Sun, 16 Mar 2014 20:49:49 -0000 (GMT)

```On 16-Mar-2014 19:38:25 Ralph Corderoy wrote:
> Hi Ted,
>
>> The values I chose for the constants in the expression were motivated
>> by aiming for a reduction by 1/cuberoot(2) as one moves up one level
>> of superscript, so that the point size of "z" in "\$X sup V sup 2 sup
>> z\$" would be about half that of X: cuberoot(2) = 1.26, 14/11 = 1.27 --
>> but only using small multipliers (since ".ps (u;\\n[.ps]*11+7/14>?5)"
>> is set to work in "u", which for PS is points*1000, so 11-point is
>> 11000u; and you could easily provoke overflow).
>
> Is this a solution?
>
>     \$ python -c 'print 2 ** (-1 / 3.0)'
>     0.793700525984
>     \$
>     \$ cat ted
>     .ps 12p
>     .tm \n[.ps]
>     .ps
> (u;(\n[.ps]*7/10)+(\n[.ps]*9/100)+(\n[.ps]*3/1000)+(\n[.ps]*7/10000)>?5z)
>     .tm \n[.ps]
>     .ps
> (u;(\n[.ps]*7/10)+(\n[.ps]*9/100)+(\n[.ps]*3/1000)+(\n[.ps]*7/10000)>?5z)
>     .tm \n[.ps]
>     .ps
> (u;(\n[.ps]*7/10)+(\n[.ps]*9/100)+(\n[.ps]*3/1000)+(\n[.ps]*7/10000)>?5z)
>     .tm \n[.ps]
>     .ps
> (u;(\n[.ps]*7/10)+(\n[.ps]*9/100)+(\n[.ps]*3/1000)+(\n[.ps]*7/10000)>?5z)
>     .tm \n[.ps]
>     .ps
> (u;(\n[.ps]*7/10)+(\n[.ps]*9/100)+(\n[.ps]*3/1000)+(\n[.ps]*7/10000)>?5z)
>     .tm \n[.ps]
>     \$
>     \$ troff ted
>     12000
>     9524
>     7557
>     5996
>     5000
>     5000
>     \$
>
> Cheers, Ralph.

A nice solution, Ralph! (Posted while I was still writing my previous
post, so I have only just now seen it). And you seem to have hit on
the solution to the ">?5" puzzle with your ">?5z"! But (see my previous
post) 'eqn' does not put the "z" in, so I think between us we have
uncovered a deficiency in 'eqn'. Quite where in the 'eqn' code this
lurks is not obvious (to me at the moment). Or maybe, as you suggest,
it is only there because of the "/10" and 'eqn' has no intention of
setting a lower limit to point-size in superscripts (though I think
that could be a flaw in itself, from the typesetting point of view).

Best wishes,
Ted.

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