[Maxima] rational to float

willisb@unk.edu willisb@unk.edu
Sat, 23 Jun 2001 07:55:05 -0500


simp.lisp incorrectly sets machine-mantissa-precision to be 24:

(eval-when (compile load)
     (defvar machine-mantissa-precision 24 );;is this correct
)

For double precision, machine-mantissa-precision  should be 53;
changing it corrects the problem with the precision of the rational
to float conversion.   For Common Lisp, float.lisp correctly defines
machine-mantissa-precision with

        MACHINE-MANTISSA-PRECISION
        #+(OR PDP10 H6180)   27.
        #+cl(integer-length (integer-decode-float most-positive-double-float))


Barton