Alignment doesn't work for array of structs (Trac #2211) #663

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1. ghost assigned

   cournape

   on Jun 28, 2013
2. charris commented on Feb 18, 2014

   

   charris

   on Feb 18, 2014

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   It's definitely not aligned, although I'm not sure it needs to be all on 4 byte boundaries.

   Still present in 1.9-devel.
3. ahaldane commented on Sep 23, 2015

   

   ahaldane

   on Sep 23, 2015

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   same bug as #5224. It is because dtype constructor ignores the align keyword for 'list of tuples' style of specification.
4. ihormelnyk commented on Oct 30, 2016

   

   ihormelnyk

   on Oct 30, 2016

   Last edited by ihormelnyk

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   Hi.
   I am wondering whether you plan to fix this bug?
   This fix is very important for our project because we use c++ python extension for high performance computations,, so numpy arrays allocated in python, should be compatible with usual c++ structs.
   And we have to build and patch numpy for every new version.

   def test_subtype_alignment(self): 
           t = np.dtype([('a', '|i1'), ('b', [('f0', '<i2'), ('f1', '<f4')])], align=True)
           self.assertEqual(t.descr, [('a', '|i1'), ('', '|V3'), ('b', [('f0', '<i2'), ('', '|V2'), ('f1', '<f4')])])
   

   #PASSED

       def test_array_of_subtype_alignment(self): 
           t = np.dtype([('a', '|i1'), ('b', [('f0', '<i2'), ('f1', '<f4')], 2)], align=True)        
           self.assertEqual(t.descr, [('a', '|i1'), ('', '|V3'), ('b', [('f0', '<i2'), ('', '|V2'), ('f1', '<f4')], (2,))])
   

   #FAILED
5. ahaldane commented on Oct 31, 2016

   

   ahaldane

   on Oct 31, 2016

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   Eventually it should be fixed. I'm not going to work on it until some other PRs get through though, so it's currently up for grabs.

   By the way, a workaround is to use the "dict" form of specification instead of the "tuple" form, as that respects "align".
6. rbalint

   added 2 commits that reference this issue on May 5, 2017

   TST: Explicity align data records in test_byte_offset()

   ...

   92276c7

   TST: Explicity align data records in test_byte_offset()

   ...

   6b22ec7
7. ahaldane

   closed this as completedin #10923on Apr 18, 2018
8. ahaldane

   added a commit that references this issue on Apr 18, 2018

   Merge pull request #10923 from ihormelnyk/master

   ...

   This issue will close once commit 8be088a is merged into the 'main' branch.

   8be088a