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Posted to issues@commons.apache.org by "Arne Plöse (JIRA)" <ji...@apache.org> on 2011/07/22 08:46:57 UTC
[jira] [Created] (MATH-627) superfluously null check of
SparseIterator.next()
superfluously null check of SparseIterator.next()
-------------------------------------------------
Key: MATH-627
URL: https://issues.apache.org/jira/browse/MATH-627
Project: Commons Math
Issue Type: Improvement
Affects Versions: 3.0
Reporter: Arne Plöse
Priority: Minor
Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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[jira] [Resolved] (MATH-627) superfluously null check of
SparseIterator.next()
Posted by "Thomas Neidhart (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-627?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Thomas Neidhart resolved MATH-627.
----------------------------------
Resolution: Fixed
Fixed in r1334198.
Thanks for the report!
> superfluously null check of SparseIterator.next()
> -------------------------------------------------
>
> Key: MATH-627
> URL: https://issues.apache.org/jira/browse/MATH-627
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Arne Plöse
> Priority: Minor
> Fix For: 3.1
>
>
> Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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[jira] [Commented] (MATH-627) superfluously null check of
SparseIterator.next()
Posted by "Thomas Neidhart (Commented) (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13254432#comment-13254432 ]
Thomas Neidhart commented on MATH-627:
--------------------------------------
I did some performance tests, and the gain is quite significant: ~50%
Removing the additional null check for the data retrieved from it.next() looks safe to me, the code would change to something like that (which btw was already there at some places):
{noformat}
while (it.hasNext()) {
final Entry e = it.next();
...
}
{noformat}
> superfluously null check of SparseIterator.next()
> -------------------------------------------------
>
> Key: MATH-627
> URL: https://issues.apache.org/jira/browse/MATH-627
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Arne Plöse
> Priority: Minor
> Fix For: 3.1
>
>
> Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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[jira] [Commented] (MATH-627) superfluously null check of
SparseIterator.next()
Posted by "Arne Plöse (Commented JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13253536#comment-13253536 ]
Arne Plöse commented on MATH-627:
---------------------------------
Sorry for beeing sloppy...
If you look at ArrayRealVector you will find this construct:
{code}
while (it.hasNext() && (e = it.next()) != null) {...}
{code}
the same can also be found in RealVector
> superfluously null check of SparseIterator.next()
> -------------------------------------------------
>
> Key: MATH-627
> URL: https://issues.apache.org/jira/browse/MATH-627
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Arne Plöse
> Priority: Minor
> Fix For: 3.1
>
>
> Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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[jira] [Updated] (MATH-627) superfluously null check of
SparseIterator.next()
Posted by "Phil Steitz (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-627?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Phil Steitz updated MATH-627:
-----------------------------
Affects Version/s: (was: 3.0)
Fix Version/s: 3.1
Optimization can wait until 3.1
> superfluously null check of SparseIterator.next()
> -------------------------------------------------
>
> Key: MATH-627
> URL: https://issues.apache.org/jira/browse/MATH-627
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Arne Plöse
> Priority: Minor
> Fix For: 3.1
>
>
> Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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This message is automatically generated by JIRA.
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[jira] [Commented] (MATH-627) superfluously null check of
SparseIterator.next()
Posted by "Thomas Neidhart (Commented) (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13253398#comment-13253398 ]
Thomas Neidhart commented on MATH-627:
--------------------------------------
I failed to find any null check in the mentioned iterator, neither in the current trunk version nor in the version at the time the issue was created. Can you please specify more precisely where the problem lies?
> superfluously null check of SparseIterator.next()
> -------------------------------------------------
>
> Key: MATH-627
> URL: https://issues.apache.org/jira/browse/MATH-627
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Arne Plöse
> Priority: Minor
> Fix For: 3.1
>
>
> Looking at the implementation of SparseIterator in OpenMapRealVector.OpenMapSparseIterator there is no chance that the entry return by next() is ever null - so there is no need to chek this in nearly every loop?
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