[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Gcl-devel] Numerical conversion between integral and float
From: |
Camm Maguire |
Subject: |
Re: [Gcl-devel] Numerical conversion between integral and float |
Date: |
19 Feb 2004 23:12:54 -0500 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 |
Greetings! Can this wait for 2.7.x? Especially as I don't know what
the right thing to is. see the recent discussion on the maxima
mailing list regarding nans and infs.
Take care,
"Mike Thomas" <address@hidden> writes:
> Hi all.
>
> On GCL the following occurs:
>
> ==================================================================
> >(- (expt 2 (expt 2 (expt 2 (expt 2 2)))) 0.5)
>
> Error in SYSTEM:TOP-LEVEL [or a callee]: Can't print a non-number.
>
> Fast links are on: do (use-fast-links nil) for debugging
> Broken at PRIN1. Type :H for Help.
> 1 (Continue) Return to top level.
> ==================================================================
>
> The integral value is too large for the floating point representation and so
> the attempt to convert for subtraction of a float doesn't work:
>
> Corman CL handles this as:
>
> (- (expt 2 (expt 2 (expt 2 (expt 2 2)))) 0.5)
> ;;; An error occurred in function -:
> ;;; Error: The number
>
> ...Giant number elided by yours truly...
>
> is too large in magnitude to be converted to a SINGLE-FLOAT
> ;;; Entering Corman Lisp debug loop.
> ;;; Use :C followed by an option to exit. Type :HELP for help.
> ;;; Restart options:
> ;;; 1 Abort to top level.
>
>
> LW eval gives:
>
> (- (expt 2 (expt 2 (expt 2 (expt 2 2)))) 0.5)
> +1D++0 #| +1D++0 is double-float plus-infinity |#
>
>
> I like the Corman message best of all, but I don't know if that is the Right
> Thing To Do re ANSI and numerical correctness.
>
> Cheers
>
> Mike Thomas.
>
>
>
>
> _______________________________________________
> Gcl-devel mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/gcl-devel
>
>
>
--
Camm Maguire address@hidden
==========================================================================
"The earth is but one country, and mankind its citizens." -- Baha'u'llah