Opened 22 months ago

Closed 11 months ago

## #31665 closed defect (duplicate)

# SymbolicRing: wrong comparison

Reported by: | zimmerma | Owned by: | |
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Priority: | critical | Milestone: | sage-duplicate/invalid/wontfix |

Component: | basic arithmetic | Keywords: | |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | #31424 | Stopgaps: |

### Description (last modified by )

consider the following with Sage 9.1 (or 9.3.rc3):

sage: t = log(17179815199/17179869184) + 727717503781781876485802752874818120860129694543334299450155913077668355/231584178474632390847141970017375815706539969331281128078915168015826259279872 sage: v = -53985/17179869184 sage: bool(abs(t) < 1.213*2^-56*v^4) # wrong False sage: R=RealIntervalField(200) sage: R(t) 1.55578750734428907680358094?e-39 sage: R(1.213*2^-56*v^4) 1.6413230032915689258596928268620690736175285393511912922960995?e-39

It seems the `bool`

evaluation is evaluated in floating-point with insufficient precision to yield a correct result.

### Change History (11)

### comment:1 Changed 22 months ago by

### comment:3 Changed 22 months ago by

Summary: | wrong comparison → SymbolicRing: wrong comparison |
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### comment:4 Changed 21 months ago by

Milestone: | sage-9.3 → sage-9.4 |
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Moving to 9.4, as 9.3 has been released.

### comment:5 Changed 18 months ago by

Milestone: | sage-9.4 → sage-9.5 |
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### comment:6 Changed 14 months ago by

Milestone: | sage-9.5 → sage-9.6 |
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### comment:7 Changed 13 months ago by

Dependencies: | → #31424 |
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Milestone: | sage-9.6 → sage-duplicate/invalid/wontfix |

Fixed in #31424.

### comment:8 Changed 13 months ago by

Status: | new → needs_review |
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### comment:9 follow-up: 10 Changed 13 months ago by

if we now get `true`

with the patch from #31424 (I did not check however), this is ok for me

### comment:10 Changed 13 months ago by

### comment:11 Changed 11 months ago by

Resolution: | → duplicate |
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Status: | needs_review → closed |

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cf #31424