adaptive sample crash if multi grid is used by a user and crash if user guide test is slightly modified

[alfoa]

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Issue Description

What did you expect to see happen?

1st issue:
Email from a user:
I was playing around with the limit surface search capability in Raven. I modified the convergence criterion in the file tests/framework/Samplers/AdaptiveLimitSurfaceSearch/test_adaptive_sampler.xml to read

 <Convergence forceIteration="False" limit="3000" subGridTol="1e-4" persistence="50" weight="cdf">1e-3</Convergence>

2nd issue:
If the goal function of the test in raven/tests/framework/user_guide/AdaptiveSamplingStrategies/adaptiveSamplingLSsearch.xml is modified as the attached one, the code crashes (see attached log file)

What did you see instead?

1st issue:
However, after a few iterations, raven stopped with the message "IndexError: pop from empty list". (If I use weight="value", then raven runs to completion.)
2nd issue:
Crash of the code:

    self.matrixDict = {varName: dataSet[varName].values for varName in self.variableDist}
TypeError: 'NoneType' object has no attribute '__getitem__'

Please attach the input file(s) that generate this error. The simpler the input, the faster we can find the issue.

1st issue:
tests/framework/Samplers/AdaptiveLimitSurfaceSearch/test_adaptive_sampler.xml

2nd issue:
tests/framework/user_guide/AdaptiveSamplingStrategies/adaptiveSamplingLSsearch.xml
fail.log
goalFunction.py.txt

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For Change Control Board: Issue Review

This review should occur before any development is performed as a response to this issue.

• 1. Is it tagged with a type: defect or improvement?
• 2. Is it tagged with a priority: critical, normal or minor?
• 3. If it will impact requirements or requirements tests, is it tagged with requirements?
• 4. If it is a defect, can it cause wrong results for users? If so an email needs to be sent to the users.
• 5. Is a rationale provided? (Such as explaining why the improvement is needed or why current code is wrong.)

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For Change Control Board: Issue Closure

This review should occur when the issue is imminently going to be closed.

• 1. If the issue is a defect, is the defect fixed?
• 2. If the issue is a defect, is the defect tested for in the regression test system? (If not explain why not.)
• 3. If the issue can impact users, has an email to the users group been written (the email should specify if the defect impacts stable or master)?
• 4. If the issue is a defect, does it impact the latest stable branch? If yes, is there any issue tagged with stable (create if needed)?
• 5. If the issue is being closed without a merge request, has an explanation of why it is being closed been provided?

[wangcj05]

This issue will impact the users. @alfoa Please write an email for the fix of this issue.

[alfoa]

Email:
Dear users,
Recently a user reported a defect in case a multi-grid LimitSurface approach was used.
The issue was appearing when a Limit Surface was not identified within a number of iteration == persistence number. The multi-grid was trying to refine the search even if no starting LS was identified. This caused the code to crash.
As PR #762, the issue has been solved and a check has been added.
Thanks
The Raven team