[ET Trac] [Einstein Toolkit] #1603: CarpetProlongateTest/test_o9 is failing on several machines

[Einstein Toolkit]

#1603: CarpetProlongateTest/test_o9 is failing on several machines
--------------------+-------------------------------------------------------
 Reporter:  hinder  |       Owner:  eschnett           
     Type:  defect  |      Status:  new                
 Priority:  major   |   Milestone:  ET_2014_05         
Component:  Carpet  |     Version:  development version
 Keywords:          |  
--------------------+-------------------------------------------------------
 CarpetProlongateTest/test_o9 is failing on Gordon, Mike and Redshift.  On
 Gordon, the differences are

 {{{
    carpetprolongatetest::difference.d.asc: substantial differences
       significant differences on 1 (out of 206) lines
       maximum absolute difference in column 13 is 1.07288360595703e-06
       maximum absolute difference in column 14 is 6.98491930961609e-10
       maximum relative difference in column 13 is 1.12625729345722e-12
       maximum relative difference in column 14 is 3
       (insignificant differences on 19 lines)
    carpetprolongatetest::difference.x.asc: differences below tolerance on
 26 lines
    carpetprolongatetest::difference.y.asc: differences below tolerance on
 26 lines
    carpetprolongatetest::errornorm..asc: differences below tolerance on 1
 lines
    carpetprolongatetest::scalar.d.asc: differences below tolerance on 13
 lines
    carpetprolongatetest::scalar.x.asc: differences below tolerance on 6
 lines
    carpetprolongatetest::scalar.y.asc: differences below tolerance on 4
 lines
 }}}

 and on the other machines the results are similar.  test.ccl contains

 {{{
 TEST test_o7
 {
   ABSTOL 2.0e-11
 }

 TEST test_o9
 {
   ABSTOL 5.0e-10
 }

 TEST test_o11
 {
   ABSTOL 3.0e-8
 }
 }}}

 Higher order prolongation probably leads to more amplification of roundoff
 differences, which is why the absolute tolerances listed here increase
 with prolongation order.

 On Redshift, which uses -Ofast with gcc, the maximum absolute differences
 in columns 13 and 14 are just marginally above the tolerance of 5e-10:

 {{{
       maximum absolute difference in column 13 is 9.31322574615479e-10
       maximum absolute difference in column 14 is 6.98491930961609e-10
       maximum relative difference in column 13 is 9.77653900570505e-16
       maximum relative difference in column 14 is 3
 }}}

 However on Gordon and Mike, the column 13 absolute difference is 1e-6,
 which presumably means the data is large, so the relative tolerance will
 come into play.  The default relative tolerance is 1e-12, and the
 difference in column 13 is marginally above this.

 Gordon:

 {{{
       maximum absolute difference in column 13 is 1.07288360595703e-06
       maximum absolute difference in column 14 is 6.98491930961609e-10
       maximum relative difference in column 13 is 1.12625729345722e-12
       maximum relative difference in column 14 is 3
 }}}

 Mike:

 {{{
       maximum absolute difference in column 13 is 1.07288360595703e-06
       maximum absolute difference in column 14 is 6.98491930961609e-10
       maximum relative difference in column 13 is 1.12625729345722e-12
       maximum relative difference in column 14 is 3
 }}}

 Should we increase both the relative and absolute tolerances for this test
 to 1e-11?  I believe that would make the test pass on all three machines.

-- 
Ticket URL: <https://trac.einsteintoolkit.org/ticket/1603>
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