Opened 14 years ago
Closed 14 years ago
#3658 closed defect (fixed)
[with patch, positive review] A PARI bug results in an unreliable prime_pi
Reported by: | fwclarke | Owned by: | craigcitro |
---|---|---|---|
Priority: | minor | Milestone: | sage-3.3 |
Component: | number theory | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | Work issues: | ||
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
---------------------------------------------------------------------- | SAGE Version 3.0.5, Release Date: 2008-07-11 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- sage: [prime_pi(n) for n in [500508..500510]] [41580, 45056, 41581] sage: [prime_pi(n) for n in [500508..500510]] [41580, 41581, 41581]
The problem lies with pari/gp:
sage: %gp --> Switching to GP/PARI interpreter <-- '' gp: for(n=500508, 500510, print(primepi(n))) 41580 45056 *** primepi: not enough precomputed primes, need primelimit ~ 500510.
Attachments (1)
Change History (8)
comment:1 Changed 14 years ago by
- Owner changed from was to craigcitro
- Status changed from new to assigned
- Summary changed from A PARI bug results in an unreliable prime_pi to [with patch, needs review] A PARI bug results in an unreliable prime_pi
comment:2 Changed 14 years ago by
- Milestone changed from sage-3.4.1 to sage-3.3
comment:3 Changed 14 years ago by
- Summary changed from [with patch, needs review] A PARI bug results in an unreliable prime_pi to [with patch, positive review] A PARI bug results in an unreliable prime_pi
works for me
comment:4 Changed 14 years ago by
- Summary changed from [with patch, positive review] A PARI bug results in an unreliable prime_pi to [with patch, needs work] A PARI bug results in an unreliable prime_pi
On sage.math: oops:
sage -t -long "devel/sage/sage/libs/pari/gen.pyx" ********************************************************************** File "/scratch/mabshoff/sage-3.3.alpha2/devel/sage/sage/libs/pari/gen.pyx", line 7400: sage: pari._primelimit() Expected: 500000 Got: 500519 **********************************************************************
Cheers,
Michael
Changed 14 years ago by
comment:5 Changed 14 years ago by
- Summary changed from [with patch, needs work] A PARI bug results in an unreliable prime_pi to [with patch, needs quick review] A PARI bug results in an unreliable prime_pi
comment:6 Changed 14 years ago by
- Summary changed from [with patch, needs quick review] A PARI bug results in an unreliable prime_pi to [with patch, positive review] A PARI bug results in an unreliable prime_pi
+1
comment:7 Changed 14 years ago by
- Resolution set to fixed
- Status changed from assigned to closed
Merged in Sage 3.3.alpha2.
Cheers,
Michael
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The attached patch fixes the issue. This was a strange case -- in some cases, Pari is more than happy to return an (incorrect!) answer when you call
primepi
with a number larger than the prime limit. This patch fixes this in a uniform way.