Bugfix 1694 main_v9.1 grid_diag

[JohnHalleyGotway]

Pull Request Testing

• Describe testing already performed for these changes:
  
  Migrating exactly the same changes for issue Fix Grid-Diag bug when reading the same variable name from multiple data sources. #1694 which PR Bugfix 1694 grid_diag #1696 merged into develop. But I'm applying these changes to the main_v9.1 branch. I made sure the code compiles, reran unit_grid_diag.xml, and confirmed the output has changed as expected.

Here's the old grid_diag output on kiowa:

ncdump /d1/projects/MET/MET_regression/main_v9.1/NB20210310/MET-main_v9.1/test_output/grid_diag/grid_diag_APCP_06_FCST_OBS.nc

1D histogram counts are duplicated!

 hist_FCST_APCP_A06 = 170628, 1427, 1144, 786, 532, 401, 285, 283, 221, 241, 
    192, 181, 180, 139, 112, 98, 87, 66, 77, 84, 70, 49, 34, 42, 23, 21, 10, 
    5, 5, 2, 3, 2, 4, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;

 hist_OBS_APCP_A06 = 170628, 1427, 1144, 786, 532, 401, 285, 283, 221, 241, 
    192, 181, 180, 139, 112, 98, 87, 66, 77, 84, 70, 49, 34, 42, 23, 21, 10, 
    5, 5, 2, 3, 2, 4, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;

Here's the new (correct) grid_diag output on kiowa:

ncdump /d1/projects/MET/MET_pull_requests/met-10.0.0_beta5/bugfix_1694/MET-bugfix_1694_main_v9.1_grid_diag_into_main_v9.1/test_output/grid_diag/grid_diag_APCP_06_FCST_OBS.nc

1D histogram counts are unique and correct:

 hist_FCST_APCP_A06 = 83326, 1160, 905, 608, 412, 306, 220, 226, 186, 181, 
    155, 151, 148, 107, 81, 76, 69, 54, 61, 67, 60, 43, 30, 36, 21, 16, 8, 3, 
    2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;

 hist_OBS_APCP_A06 = 87302, 267, 239, 178, 120, 95, 65, 57, 35, 60, 37, 30, 
    32, 32, 31, 22, 18, 12, 16, 17, 10, 6, 4, 6, 2, 5, 2, 2, 3, 2, 3, 2, 4, 
    0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  
  Please compare the modified files to the change for develop PR:
  https://github.com/dtcenter/MET/pull/1696/files

If there's anything you'd like to run, you can find it compiled on kiowa in:
/d1/projects/MET/MET_pull_requests/met-10.0.0_beta5/bugfix_1694/MET-bugfix_1694_main_v9.1_grid_diag_into_main_v9.1/met

• Do these changes include sufficient documentation and testing updates? [Yes]

• Will this PR result in changes to the test suite? [Yes]
  
  If yes, describe the new output and/or changes to the existing output:
  
  The output for an existing unit_grid_diag.xml test will change, as it did in the develop branch. So I'll need to update the reference version when it does.

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[jprestop]

I compared the modified files to the change for develop PR. Thanks for the link! The changes were comparable. I did not do any other testing. I approve this request.