[Einstein Toolkit] #1605: Multipole convergence order test is sensitive to roundoff - Trac

30 Apr 2014


      #1605: Multipole convergence order test is sensitive to roundoff
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 Reporter:  hinder                 |       Owner:                     
     Type:  defect                 |      Status:  new                
 Priority:  major                  |   Milestone:  ET_2014_05         
Component:  EinsteinToolkit thorn  |     Version:  development version
 Keywords:                         |  
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 The integration convergence test performed by Multipole is sensitive to
 roundoff, as the relative error is ~1e-7 in the Simpson case. This is
 important only during the correctness test, not for general use of the
 thorn.  The computation of the convergence order includes a subtraction of
 the exact from the numerical result, and this loses many digits of
 precision in the final convergence order.  This causes the simpson test to
 fail on several machines.  So, while it is useful to have the convergence
 order output, this is not a good regression test. The attached set of
 patches output the integration results, and raise the tolerance of the
 convergence order to 1e-3.  The tolerance for the integration results is
 left at the default.  The tests all pass on Datura, though they also did
 before this change.
OK to commit?
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Ticket URL: https://trac.einsteintoolkit.org/ticket/1605
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