#2160: QuasiLocalMeasures qlm_spin doesn't work for spins not aligned along the z axis
Reporter:
Status:wontfix
Milestone:
Version:development version
Type:bug
Priority:minor
Component:EinsteinToolkit thorn

Changes (by Roland Haas):

status:wontfix (was new)

Einstein Toolkit version: ET_2018_02.

Parameter file: qc0-mclachlan.par in einsteinexamples with the additional parameter TwoPunctures::par_S_plus [0] = +0.3

Problem: The diagnostic qlm_spin[0] returns a spin of 0, whereas the expected one should be 0.3.

If instead of TwoPunctures::par_S_plus [1] = +0.3 one sets TwoPunctures::par_S_plus [2] = +0.3, qlm_spin[0] is correctly outputting 0.3

This happens because QuasiLocalMeasures finds in both cases the rotational Killing vector d/dphi (as seen setting QuasiLocalMeasures::veryverbose = yes), which is correct in the second case (when the axis aligned with the z-direction), but doesn't sound right when the rotation is with respect to the x-axis.

Changing QuasiLocalMeasures::killing_vector_method to axial or gradient does not change the outcome.

Best regards, Gabriele

Keyword: QuasiLocalMeasures

Comment (by Roland Haas):

Works as designed. This limit should be documented.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2160/quasilocalmeasures-qlm_spin-doesnt-work