Verify check for small determinant in PatPV3DFuture xPointParameters
Usually the determinant is checked for consistency with zero as this means that the matrix has no inverse. https://gitlab.cern.ch/lhcb/Rec/-/blob/6c5b74f8751f8d2ccca1c86abf98e045bb7a9e5f/Tr/PatPV/src/PatPV3DFuture.cpp#L343 checks for an arbitrary value of smaller than 10e-6.
The following discussion from !3612 (merged) should be addressed:
-
@gunther started a discussion: (+8 comments) is this correct? usually you only need to test if the determinant is zero