Polygon Intersection Bug

[raquelalvarezbanos]

We observed this problem via ConvertToReflectometryQ.
This was reported by Jos. The following script:

r=s.Runs()
dref=s.OurLoad(r[36265,36266,36267,36268])
MoveInstrumentComponent(dref,'DetectorBench',Y=0.0404)
#dtrans=s.OurLoad(r[36252])

Transo=CreateTransmissionWorkspaceAuto(dtrans,AnalysisMode="MultiDetectorAnalysis",ProcessingInstructions="380-428",WavelengthMin=2.0)
IvsQ2o, IvsLam2o, thetaOut=ReflectometryReductionOneAuto(dref,AnalysisMode="MultiDetectorAnalysis",ProcessingInstructions="390-450", FirstTransmissionRun=Transo, ThetaIn="0.64",WavelengthMin=2.0,CorrectionAlgorithm='None',StrictSpectrumChecking=False,CorrectDetectorPositions=False)#,NormalizeByIntegratedMonitors=False
IvsQo, IvsLamo, thetaOut=ReflectometryReductionOneAuto(dref,AnalysisMode="MultiDetectorAnalysis",ProcessingInstructions=','.join(map(str, range(250, 558))), FirstTransmissionRun=Transo, ThetaIn="0.64",WavelengthMin=2.0,CorrectionAlgorithm='None',StrictSpectrumChecking=False,CorrectDetectorPositions=False)#,NormalizeByIntegratedMonitors=False
TvLo = ConvertSpectrumAxis(IvsLamo,'SignedTheta')

ConvertToReflectometryQ(TvLo,IncidentTheta=0.64,DumpVertexes=True,OverrideIncidentTheta=True, OutputWorkspace="QxQz",OutputVertexes="Qtableo",Extents=[-1.2e-6,-6.67e-7,0.01034,0.010388],NumberBinsQz=4,NumberBinsQx=4,Method='NormalisedPolygon',OutputAsMDWorkspace=False)

produces a NaN value (white bin):

The bug is caused by the V2D equality operator, which uses a standard tolerance value 1e-6 (too high in some cases). This makes PolygonIntersection fail when calculating the intersection if one of the polygons is small enough.