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#109 Floats default to single precision
XSB seems to use single precision float internally.
See the folloing query and response:
| ?- X = 123456700.0 , Y = 89.0, Z is X + Y.
X = 123456704.0000
Y = 89.0000
Z = 123456768.0000
Z should be 123456789.0
This is a "wrong answer" if you consider that most
other platforms default to double precision float.
XSB version 2.7 on Windows 2000 and Linux (Debian
sarge).
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This limitation makes XSB useless for numerical work.
Traditional implementations of Prolog on 32-bit hardware
"box" floating point numbers and large integers.
A simpler solution would be to have a force-64-bit
configuration option to allocate 64 bits for integers,
floats and pointers. This would waste 32 bits for single
pointers, but would save 32 bits for every value that would
otherwise need to be boxed. Other key datatypes, such as
cons cells would fit in one 64-bit double word.
I tried to modify the sources to force everything to 64-bits
but apparently there are some subtleties. Would someone who
understands XSB internals please add such an option?
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Double precision floats were added for 2.7.1 -- so I'm closing this one out.
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user_id=13011
Originator: NO
Double precision floats were added for 2.7.1 -- so I'm closing this one out.
Logged In: YES
user_id=13011
Originator: NO
Double precision floats were added for 2.7.1 -- so I'm closing this one out.