[Users] Failed to calculate the magnitude of the horizon spin in precessing BBH system

[刘屿]

Dear Cactus users,

I am trying to simulate a precessing BBH system. When I analysed the mass
of the black hole (qlm_mass), I found that the spin evolution (qlm_spin) is
abnormal.
[image: qlm_spin.png]
The coordinate-base spin vector gives a value closer to what I set.
[image: qlm_coordspin_norm.png]
This is the initial parameters.

ADMMass = 0.9898872694943947
Mass Ratio = 1.0
separation = 10.4
spin1 = [-0.125  0.     0.   ]
spin2 = [0.125 0.    0.   ]
chi1 = [-0.5  0.   0. ]
chi2 = [0.5 0.  0. ]


I tried different methods for finding the killing vector field (i.e.
QuasiLocalMeasures::killing_vector_method), but it didn't work.

If the small black hole does not spin (spin2 = [0, 0, 0]), things will get
better.

The following is the difference between my parfile and GW150914.rpar

$ diff GW150914.rpar BBH000.rpar
32,33c32,33
< D = 10.0                    # Separation
< q = 36.0/29.0               # Mass ratio: q = mp/mm >= 1
---
> D = 10.4                    # Separation
> q = 1              # Mass ratio: q = mp/mm >= 1
35,38c35,38
< chip = [0, 0,  0.31]        # Dimensionsless spin of + BH (x0 > 0, more
massive)
< chim = [0, 0, -0.46]        # Dimensionsless spin of - BH (x0 < 0, less
massive)
< Pr = -0.00084541526517121;  # Radial linear momentum
< Pphi = 0.09530152296974252; # Azimuthal linear momentum
---
> chip = [-0.5, 0, 0]        # Dimensionsless spin of + BH (x0 > 0, more
massive)
> chim = [0.5, 0, 0]        # Dimensionsless spin of - BH (x0 < 0, less
massive)
> Pr = -0.000878483532190008
> Pphi = 0.0927554222753844
261,265c261,265
< CoordinatesSymmetry::reflection_z       = yes
< CoordinatesSymmetry::stagger            = no
< Coordinates::symmetry                   = "+z bitant"
< Coordinates::additional_symmetry_size   = 1
< Coordinates::verbose                    = no
---
> ##CoordinatesSymmetry::reflection_z       = yes
> ##CoordinatesSymmetry::stagger            = no
> ##Coordinates::symmetry                   = "+z bitant"
> ##Coordinates::additional_symmetry_size   = 1
> ##Coordinates::verbose                    = no
552,553c552,553
< SphericalSurface::maxntheta             = 66
< SphericalSurface::maxnphi               = 124
---
> SphericalSurface::maxntheta             = 161
> SphericalSurface::maxnphi               = 320
559,560c559,560
< SphericalSurface::ntheta            [2] = 41
< SphericalSurface::nphi              [2] = 80
---
> SphericalSurface::ntheta            [2] = 161
> SphericalSurface::nphi              [2] = 320
565,566c565,566
< SphericalSurface::ntheta            [3] = 41
< SphericalSurface::nphi              [3] = 80
---
> SphericalSurface::ntheta            [3] = 161
> SphericalSurface::nphi              [3] = 320
571,572c571,572
< SphericalSurface::ntheta            [4] = 41
< SphericalSurface::nphi              [4] = 80
---
> SphericalSurface::ntheta            [4] = 161
> SphericalSurface::nphi              [4] = 320
633,634c633,638
< IOScalar::outScalar_reductions          = "minimum maximum average"
< IOScalar::outScalar_vars                =
"SystemStatistics::process_memory_mb"
---
> IOScalar::outScalar_reductions          = "minimum maximum average norm1
norm2"
> IOScalar::outScalar_vars                = "
>   SystemStatistics::process_memory_mb
>   ML_ADMConstraints::ML_Ham
>   ML_ADMConstraints::ML_mom
> "
670c674
< IOHDF5::out2D_every                     = $out2d_every
---
> IOHDF5::out2D_every                     = 0


Thank You
Best Regards

---------------------------

Yu Liu
PhD Student
Department of Astronomy
Huazhong University of Science and Technology
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