Ticket #1154 (closed defect: duplicate)

Opened 3 years ago

Last modified 3 years ago

lost precision in RQDF -> RealField conversion

Reported by: zimmerma Owned by: jkantor
Priority: major Milestone: sage-2.8.15
Component: numerical Keywords:
Cc: Author(s):
Report Upstream: Reviewer(s):
Merged in: Work issues:

Description 

sage: R = RealField(206)
sage: a = R(5292635226105886036954352397762172773270339156347702272822435/2^205)
sage: b = RQDF(a)
sage: c = R(b)
self= 0.102925468350634334254648605229306925849343943655945448198193123
sage: a - c
1.215432671457254239676575010503930515740283626703352955683812e-63

I checked with b.get_doubles() that b == a, but was unable to find the routine which performs the conversion from b (RQDF) to c (RealField?). It seems R._set_from_qd is not used.

Change History

Changed 3 years ago by mabshoff

  • milestone set to sage-2.8.13

Changed 3 years ago by cwitty

  • status changed from new to closed
  • resolution set to duplicate

This is one of the issues that's covered by the patch at #1162.

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