Opened 5 years ago

Closed 4 years ago

Last modified 4 years ago

#24397 closed defect (wontfix)

Expression._convert should not make exact function arguments inexact

Reported by: rws Owned by:
Priority: major Milestone: sage-duplicate/invalid/wontfix
Component: symbolics Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: Reported upstream. Developers deny it's a bug. Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Status badges


sage: f = function('f')
sage: f(1, 2)._convert(RR)
f(1.00000000000000, 2.00000000000000)

This loses information that might be needed by the function. Some functions might even require exact arguments for correct results.

This ticket tracks and doctests the Pynac fix.

Change History (4)

comment:1 Changed 5 years ago by rws

  • Milestone changed from sage-8.2 to sage-duplicate/invalid/wontfix
  • Report Upstream changed from Reported upstream. Developers acknowledge bug. to Reported upstream. Developers deny it's a bug.
  • Status changed from new to needs_review

We are scratching at the fundamental design decisions here. FP evaluation of expressions is implemented by walking the expression tree depth-first and converting exact and inexact numeric to inexact numeric. The end result is either inexact numeric or an expression containing symbols. This process is inherently fast because only inexact operations are done. We don't want to change it fundamentally.

The bug that sparked this ticket can be resolved differently anyway.

comment:2 Changed 5 years ago by rws

  • Status changed from needs_review to positive_review

comment:3 Changed 4 years ago by vdelecroix

  • Resolution set to wontfix
  • Status changed from positive_review to closed

closing positively reviewed duplicates

comment:4 Changed 4 years ago by slelievre

Is there a reference for the upstream bug report and discussion?

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