About 8 years ago I spent a long time making sure that precision was handled correctly in converting between Sage and pari. Since then the interface has totally changed and possibly these recent changes are at fault.
Jeroen do you know the answer? On 12 Feb 2017 20:14, "Nils Bruin" <[email protected]> wrote: On Sunday, February 12, 2017 at 10:59:06 AM UTC-8, Matthias Goerner wrote: > > Careful: you are changing the default precision before calling dilog. That > might mask the problem with pari's dilog. Indeed, the dilog is just implemented as self._parent(self._pari_(). dilog()) and: sage: U=ComplexField(300)(1/2+sqrt(-3)/2) sage: U._pari_() 0.500000000000000 + 0.866025403784439*I so the thing the dilog is taken of doesn't even have the right precision Also, the number of digits computed by dilog is dependent on the default precision. It looks like all the uses of pari to compute numerical results should take care to manipulate the default precision properly (as is necessary and done for mpmath use) -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout. -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
