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Re: E.P E. E.EXACT

From peter <peter.noreply@tin.it>
Newsgroups comp.lang.forth
Subject Re: E.P E. E.EXACT
Date 2026-08-12 18:03 +0200
Organization A noiseless patient Spider
Message-ID <20260812180329.0000258a@tin.it> (permalink)
References (7 earlier) <6a76b305$1@news.ausics.net> <2026Aug8.083201@mips.complang.tuwien.ac.at> <115e3r1$3l8a0$1@dont-email.me> <2026Aug11.065636@mips.complang.tuwien.ac.at> <115gojb$ghb5$1@dont-email.me>

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On Tue, 11 Aug 2026 22:16:56 -0500
Krishna Myneni <krishna.myneni@ccreweb.org> wrote:

> On 8/10/26 23:56, Anton Ertl wrote:
> > Krishna Myneni <krishna.myneni@ccreweb.org> writes:
> >> On 8/8/26 01:32, Anton Ertl wrote:
> >>> F. specifies a required ".", but that's missing here.
> >>>
> >> The only indication in the standard that a trailing "." appears is the
> >> example in the appendix; otherwise, my reading of the standard is
> >> ambiguous on the trailing decimal point.
> > 
> > The standard specifies:
> > 
> > | 12.6.2.1427 F.
> > | [...]
> > | [-] <digits>.<digits0>
> > 
> > If they intended the "." to be optional, they would have specified that as
> > 
> > [-] <digits>[.<digits0>]
> > 
> >> It should be explicitly stated
> >> if the trailing decimal point was the intent.
> > 
> > It is.
> > 
> 
> Actually, F. in its present functionality in kForth works for me, 
> despite it being non-standard. It provides 6 significant digits of 
> output and switches between fixed point and scientific notation to 
> produce the shortest output with 6 significant digits. This output is 
> useful to me most of the time. The trailing decimal point seems like a 
> good idea when it's output is in fixed point format.

This is how I just implemented Anton's E. in my system. Precision fixed
at 6 digits, print both F. and FS. to memory and take the shortest 
to print out. I found that to be a useful tool to use interactively.

Peter

> 
> When I need control over the number of significant digits displayed, I 
> use SET-PRECISION and FS. and when I need fixed point output with a 
> fixed number of decimal places, right-justified within a field of 
> specified width, I use F.RD (defined in source in strings.4th). These 
> three words, "F." "FS." and "F.RD", in their present functionality, have 
> met all of my needs up to now.
> 
> FS. can print an arbitrary number of digits.
> 
> Example:
> 
> pad 8 erase
>   ok
> 1 pad !
>   ok
> 800 set-precision
>   ok
> pad f@ fs.  \ ignore spaces and line breaks in output below
>    4.
>    940 656 458 412 465 441 765 687 928 682
>    213 723 650 598 026 143 247 644 255 856
>    825 006 755 072 702 087 518 652 998 363
>    616 359 923 797 965 646 954 457 177 309
>    266 567 103 559 397 963 987 747 960 107
>    818 781 263 007 131 903 114 045 278 458
>    171 678 489 821 036 887 186 360 569 987
>    307 230 500 063 874 091 535 649 843 873
>    124 733 972 731 696 151 400 317 153 853
>    980 741 262 385 655 911 710 266 585 566
>    867 681 870 395 603 106 249 319 452 715
>    914 924 553 293 054 565 444 011 274 801
>    297 099 995 419 319 894 090 804 165 633
>    245 247 571 478 690 147 267 801 593 552
>    386 115 501 348 035 264 934 720 193 790
>    268 107 107 491 703 332 226 844 753 335
>    720 832 431 936 092 382 893 458 368 060
>    106 011 506 169 809 753 078 342 277 318
>    329 247 904 982 524 730 776 375 927 247
>    874 656 084 778 203 734 469 699 533 647
>    017 972 677 717 585 125 660 551 199 131
>    504 891 101 451 037 862 738 167 250 955
>    837 389 733 598 993 664 809 941 164 205
>    702 637 090 279 242 767 544 565 229 087
>    538 682 506 419 718 265 533 447 265 625
>    000 000 000 000 000 000 000 000 000 000
>    000 000 000 000 000 000 0
> e-324  ok
> 
> There are 751 significant digits, representing 2^-1074. The bit pattern 
> is an IEEE double precision *subnormal* number interpreted as 
> 2^-52*(2^emin), where emin = -1022 is the minimum power of 2 exponent. 
> 2^-52 is the significand, which is the 1 stored in the lsb of the 
> binary64 floating point number.
> 
> Wolfram alpha can be used to verify all of the digits printed above.
> 
> We should be able to do this arithmetic with the big arithmetic package, 
> but I get a segfault because the output buffer is too small, I think. It 
> should be fixable.
> 
> --
> Krishna
> 
> 
> 
> 
>

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Thread

E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-05 18:02 +0000
  Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-06 08:13 -0500
    Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-06 14:00 +0000
      Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-06 10:45 -0500
        Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-06 15:58 +0000
          Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-06 17:20 +0000
        Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-06 21:05 +0200
          Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-06 20:38 +0000
          Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-06 18:44 -0500
          Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-07 11:03 +1000
            Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-07 10:11 +0000
              Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-08 14:39 +1000
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-08 06:32 +0000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-09 04:50 +1000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-10 20:01 +1000
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-10 18:06 +0000
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-10 17:24 +0000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-11 14:01 +1000
                Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-10 22:10 -0500
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-11 04:56 +0000
                Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-11 22:16 -0500
                Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-12 05:47 -0500
                Re: E.P E. E.EXACT peter <peter.noreply@tin.it> - 2026-08-12 18:03 +0200
                Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-12 11:48 -0500
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-08 09:14 +0200
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-08 09:40 +0000
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-08 15:26 +0200
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-10 16:43 +0000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-09 13:43 +1000
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-09 07:19 +0200
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-10 19:15 +1000
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-10 13:17 +0200
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-10 22:59 +1000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-10 23:54 +1000
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-10 20:42 +0200
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-11 17:10 +1000
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-12 14:04 +1000
                Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 16:43 +0200
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-22 15:47 +0000
                Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 18:27 +0200
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-22 16:40 +0000
                Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 19:42 +0200
                Re: E.P E. E.EXACT anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-22 18:03 +0000
                Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 22:56 +0200
                Re: E.P E. E.EXACT marcel hendrix <mhx@iae.nl> - 2026-08-23 00:50 +0200
                Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-23 12:25 +1000
                Re: E.P E. E.EXACT Hans Bezemer <the.beez.speaks@gmail.com> - 2026-08-09 14:52 +0200
            Re: E.P E. E.EXACT Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-07 07:50 -0500
              Re: E.P E. E.EXACT dxf <dxforth@gmail.com> - 2026-08-08 12:33 +1000
                Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 17:01 +0200
          Re: E.P E. E.EXACT albert@spenarnc.xs4all.nl - 2026-08-22 16:15 +0200

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