Some tests are failing randomly from time to time

[olekscode]

This is probably because they don't set the random state.
For example:

• PMQRTest >> testMPInverse

[hemalvarambhia]

I've begun looking into this. Could you clarify what should happen when random state is set, please? As an alternative, I wondered whether a simpler test could be written. The current one is difficult for me to follow.

[hemalvarambhia]

I've begun carefully refactoring the testMoorePenroseInverse test to enhance clarity (Four Elements of Simple Design).

To effectively test the Moore Penrose Inverse computation, is it necessary to set random state, @olekscode ? Due to my complete ignorance I am unsure of why.

Thank you.

[hemalvarambhia]

Another test that's failing is

PMNumericalMethodsTestCase
[1496](https://github.com/PolyMathOrg/PolyMath/runs/7117052304?check_suite_focus=true#step:4:1497)
 ✗ #testOptimizeOneDimension (12ms)

[hemalvarambhia]

Another test that's failing erratically:

PMGeneralFunctionFitTest
[1484](https://github.com/PolyMathOrg/PolyMath/runs/7119999338?check_suite_focus=true#step:4:1485)
 ✗ #testMaximumIterationsProbabilistic (1009ms)

[hemalvarambhia]

testQRFactorisation in PMQRTest fails erratically

[hemalvarambhia]

@olekscode I think I managed to corner the input matrix that is responsible for the erratically failing test:

testInputOfErraticFailure

| a |
a := PMSymmetricMatrix rows:
    #( #( 0.41929313699681925 0.05975350554089691
          0.2771676258543356 0.35628773381760703 )
       #( 0.05975350554089691 0.12794227252152854
          0.3257742693302102 0.28814463284245906 )
       #( 0.2771676258543356 0.3257742693302102 0.8468441832097453
          0.9101872061892353 )
       #( 0.35628773381760703 0.28814463284245906
          0.9101872061892353 0.5163744224777326 ) ).

self assert: (a mpInverse closeTo: a inverse)

This fails for the same reason as highlighted during the CI run. Thus we have a deterministic test we can use to corner the failure much more.

If you'd like to investigate with me, you can find this in investigate-erratic-test

Does the above matrix relate in some way to your hypothesis of not setting the random state.

My investigate points to an array (3 4 3 nil) - the nil appears to be the cause.

[jecisc]

Another test that's failing is

PMNumericalMethodsTestCase
[1496](https://github.com/PolyMathOrg/PolyMath/runs/7117052304?check_suite_focus=true#step:4:1497)
 ✗ #testOptimizeOneDimension (12ms)

I confirm this random failure:

PMNumericalMethodsTestCase
✗ #testOptimizeOneDimension (12ms)
TestFailure: Assertion failed
PMNumericalMethodsTestCase(TestAsserter)>>assert:description:resumable:
PMNumericalMethodsTestCase(TestAsserter)>>assert:description:
PMNumericalMethodsTestCase(Object)>>assert:
PMNumericalMethodsTestCase>>testOptimizeOneDimension ...assert: (maximum - 5) abs < 1.0e-6
PMNumericalMethodsTestCase(TestCase)>>performTest

[jecisc]

This is probably because they don't set the random state. For example:

* PMQRTest >> testMPInverse

I fixed this one and all related to random matrix and vectors: PolyMathOrg/vector-matrix@5fb38e9