On 1/26/12 7:54 AM, Marco Streng wrote:
2012/1/26 Jason Grout<jason-s...@creativetrax.com>:
That's part of the problem pointed out in an earlier message---our RR
matrices really are pretty bad for numerical things, but RDF matrices are
the way to go (the RDF matrices use standard numerical algorithms for the
most part, whereas RR matrices use naive algorithms that can be really bad
and slow). This should be fixed, but for right now, RR matrices don't seem
to be all that useful compared to RDF matrices.
Is RDF always better than 53-bit RR in this way? If so, perhaps
"RealNumber" or the preparser could be changed to use RDF if the
precision is sufficiently small. Most users typing 12.345 will want
the fastest implementation and not something generic.
No, this is a linear algebra problem, not a general problem in Sage.
Usually RR is better mathematically than RDF.
Thanks,
Jason
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