[ET Trac] [Einstein Toolkit] #1995: McLachlan constraint tests fail

[Einstein Toolkit]

#1995: McLachlan constraint tests fail
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  Reporter:  hinder                 |       Owner:                                                   
      Type:  defect                 |      Status:  confirmed                                        
  Priority:  critical               |   Milestone:  ET_2017_05                                       
 Component:  EinsteinToolkit thorn  |     Version:  development version                              
Resolution:                         |    Keywords:  McLachlan constraints tests compiler optimization
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Comment (by hinder):

 I have written a new test in ML_BSSN_Test which uses the shifted gauge
 wave from EinsteinExact and outputs the constraints as calculated by
 ML_ADMConstraints.  This test suffers from the same problem.  The test
 fails when run with Intel 17.0.4, while the test data was generated using
 gcc 4.9.2.  I have pushed the test to master, since it's always good to
 have more tests.  This eliminates the possibility that the problem is
 caused by "irregular" or strange initial data.

 I have also tried adding
 {{{
 printf("Hello World!\n");"
 }}}
 as the last line of the loop in ML_ADMConstraints_evaluate_Body.  This
 causes the test to pass, whereas previously it failed.  If the problem is
 so sensitive to changes in the code, I'm worried that it will be difficult
 to produce a cut-down example to send to Intel.  On the other hand, if
 doing something as drastic as disabling vectorisation doesn't cause the
 bug to go away, then maybe there is hope.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1995#comment:43>
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