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Macaulay2 / M2

The primary source code repository for Macaulay2, a system for computing in commutative algebra, algebraic geometry and related fields.
https://macaulay2.com
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lift breaks #921

Open DanGrayson opened 5 years ago

DanGrayson commented 5 years ago

see https://groups.google.com/forum/#!topic/macaulay2/QowiaTEHIqo

rz501 commented 5 years ago

I see at least two separate problems. The first is that R=CC[]; lift(1_R,QQ) breaks because RR is on the R.baseRings path, not default RR (or better, the one with the precision of CC). The second is that R=RR[]; lift(1_R,QQ) fails because it calls repeatedly r = rawLift(raw B, r) for B in the reversed base ring list, but the corresponding case in ConcreteRing<RingType>::lift() in e/aring-glue.hpp isn't implemented. Instead lift(1.0, QQ) works because it's implemented directly in m2/reals.m2.

Any suggestions what the path of least resistance is? Thanks in advance!