Long-float variant giving more precision to numerical computations.
Subject: Long-float variant giving more precision to numerical computations.
From: Douglas Crosher
Date: Thu, 14 Feb 2008 01:46:23 +1100
Hello,
Reworking the changes to use the maxima 'flonum type appears to work on GCL, CMUCL,
and CLISP. The following changes are proposed as a first step:
1. Replace all float constants with the general form, e.g. 1d0 -> 1e0, and increase
the precision to at least quad float precision. The *read-default-float-format*
can then be modified to change all constants to an alternative format.
2. Replace all references to the double-float type with the 'flonum type, allowing
the format used for a 'flonum to be changed easily.
The handling of the Fortran code needs more thought, so would not be changed yet.
Extending f2cl to allow translating the Fortran double precision type to a long-float
or other type may be cleaner.
An attempt has been made to use the CMUCL double-double-float type, and it does build
but there are a few problems in CMUCL that need work, such as (rationalize 0.25w0)
failing, and the lack of constants such as double-double-float-epsilon. If anyone
wants patches then just let me know.
Regards
Douglas Crosher