If you really wanted to do something useful with transmitting maxima bigfloats to other components of Sage, you should probably include it in the setting of fpprec, or perhaps the internal lisp value accessible as ?fpprec, which is the number of binary digits in the fraction part of the representation. There distinction may not e made between 123.0b0 and 123.00000000b0. because the setting of fpprintprec clouds that. But I thought Sage would use MPFR.... It is possible to get Maxima/Lisp to access MPFR, and probably not too hard to make a hackish replacement for the built-in bigfloats. A nicely integrated system would be harder. It might be worthwhile if bigfloat speed was a bottleneck.
On Monday, July 22, 2013 9:36:04 AM UTC-7, Jesus Torrado wrote: > > Hi all, > > Coming from: > https://groups.google.com/forum/#!topic/sage-support/vv6yvZMVFAQ > > Thanks, Rob! So it seems Sage does not interpret correctly some Maxima > numbers. > > In particular, I have noticed two issues: > > 1) Big floats: > > sage: maxima("bfloat(2e-4)") > 2.0b-4 > sage: maxima("bfloat(2e-4)").sage() > 2.0*b - 4 > > So the "b" as an exponential sign is treated as a variable, producing some > funny behaviour: > > sage: maxima("2*bfloat(2e-4)").sage() > 4.0*b - 4 > sage: 2*maxima("bfloat(2e-4)").sage() > 4.0*b - 8 > > 2) Long floats: > > Though Maxima does not understand directly "l" as an exponential sign, we > get the current output: > > sage: maxima("spherical_bessel_j(100,10.1)") > 15.696490570126766l-90 > > turns into > > sage: spherical_bessel_J(100,10.1) > 15.6964905701*l - 90 > > with the same nasty consequences. > > I have traced the issue down to > "sage.calculus.calculus.symbolic_expression_from_maxima_string" at > "calculus/calculus.py", for which, a couple of lines before, a regular > expression is defined to deal with scientific notation: > > sci_not = re.compile("(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]\d+)") > > I guess the issue would be solved by adding "lLbB" to the regular > expression, but I am not sure if it would break anything. I didn't have > time to test yet. > > Should I open a ticket and investigate it further? Or can any one tell the > origin of the problem is completely different, or it should be treated some > other way? > > Cheers, > Jesús Torrado > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
