Yu Liu QuasiLocalMeasures regular spin measurement assumes that the black hole spin is roughly aligned with the z direction. A spin near the equatorial plane does not work well. In this case you'll have to use the coordinate spins (qlm_coordspinx, qlm_coordspiny, qlm_coordspinz); these are less accurate for distorted black holes, but will still work very well under these circumstances.
-erik On Thu, Apr 22, 2021 at 10:43 PM 刘屿 <[email protected]> wrote: > 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 > _______________________________________________ > Users mailing list > [email protected] > http://lists.einsteintoolkit.org/mailman/listinfo/users > -- Erik Schnetter <[email protected]> http://www.perimeterinstitute.ca/personal/eschnetter/
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