[Maxima] float ^ rational bug in 5.12

Barton Willis willisb at unk.edu
Sun Aug 5 14:05:45 CDT 2007


Either I never knew about number_pbranch, or I had forgotten about it.
I think the function exprl needs some work -- it seems to be the cause
of the (negative float)^rational bug. It's too late to fix it for
5.13. We'll need to decide how numer_pbranch and domain should work.
That will take some time.

(%i1) numer_pbranch : true$
(%i2) domain : complex$

(%i3) (-4.2)^(2/3);
(%o3) (1.0*(-1)^(2/3)*21^(2/3))/5^(2/3)

(%i4) rectform(%);
(%o4) (0.5*sqrt(3)*21^(2/3)*%i)/5^(2/3)-(0.5*21^(2/3))/5^(2/3)

(%i5) float(%);
(%o5) 2.254395758285868*%i-1.301575997906296


Barton


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