<div dir="ltr"><div dir="ltr">Yu Liu<div><br></div><div>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.</div><div><br></div><div>-erik</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 22, 2021 at 10:43 PM 刘屿 <<a href="mailto:yuliumutian@gmail.com">yuliumutian@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div class="gmail_default"><div class="gmail_default" style="font-size:large">Dear Cactus users, </div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">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.</div><div class="gmail_default" style="font-size:large"><img src="cid:ii_kntpgi333" alt="qlm_spin.png" width="432" height="288"><br></div><div class="gmail_default" style="font-size:large">The coordinate-base spin vector gives a value closer to what I set.</div><div class="gmail_default" style="font-size:large"><img src="cid:ii_kntoza9a2" alt="qlm_coordspin_norm.png" width="432" height="288"><br></div><div class="gmail_default" style="font-size:large">This is the initial parameters.</div><div class="gmail_default" style="font-size:large"><pre style="box-sizing:unset;font-size:14px;border:none;margin-top:0px;margin-bottom:0px;padding:0px;overflow:auto;word-break:break-all;word-wrap:break-word;white-space:pre-wrap">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. ]</pre></div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">I tried different methods for finding the killing vector field (i.e. QuasiLocalMeasures::killing_vector_method), but it didn't work.</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">If the small black hole does not spin (spin2 = [0, 0, 0]), things will get better.</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">The following is the difference between my parfile and GW150914.rpar</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">$ diff GW150914.rpar BBH000.rpar</div><div class="gmail_default" style="font-size:large">32,33c32,33</div><div class="gmail_default" style="font-size:large">< D = 10.0 # Separation</div><div class="gmail_default" style="font-size:large">< q = 36.0/29.0 # Mass ratio: q = mp/mm >= 1</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> D = 10.4 # Separation</div><div class="gmail_default" style="font-size:large">> q = 1 # Mass ratio: q = mp/mm >= 1</div><div class="gmail_default" style="font-size:large">35,38c35,38</div><div class="gmail_default" style="font-size:large">< chip = [0, 0, 0.31] # Dimensionsless spin of + BH (x0 > 0, more massive)</div><div class="gmail_default" style="font-size:large">< chim = [0, 0, -0.46] # Dimensionsless spin of - BH (x0 < 0, less massive)</div><div class="gmail_default" style="font-size:large">< Pr = -0.00084541526517121; # Radial linear momentum</div><div class="gmail_default" style="font-size:large">< Pphi = 0.09530152296974252; # Azimuthal linear momentum</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> chip = [-0.5, 0, 0] # Dimensionsless spin of + BH (x0 > 0, more massive)</div><div class="gmail_default" style="font-size:large">> chim = [0.5, 0, 0] # Dimensionsless spin of - BH (x0 < 0, less massive)</div><div class="gmail_default" style="font-size:large">> Pr = -0.000878483532190008</div><div class="gmail_default" style="font-size:large">> Pphi = 0.0927554222753844</div><div class="gmail_default" style="font-size:large">261,265c261,265</div><div class="gmail_default" style="font-size:large">< CoordinatesSymmetry::reflection_z = yes</div><div class="gmail_default" style="font-size:large">< CoordinatesSymmetry::stagger = no</div><div class="gmail_default" style="font-size:large">< Coordinates::symmetry = "+z bitant"</div><div class="gmail_default" style="font-size:large">< Coordinates::additional_symmetry_size = 1</div><div class="gmail_default" style="font-size:large">< Coordinates::verbose = no</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> ##CoordinatesSymmetry::reflection_z = yes</div><div class="gmail_default" style="font-size:large">> ##CoordinatesSymmetry::stagger = no</div><div class="gmail_default" style="font-size:large">> ##Coordinates::symmetry = "+z bitant"</div><div class="gmail_default" style="font-size:large">> ##Coordinates::additional_symmetry_size = 1</div><div class="gmail_default" style="font-size:large">> ##Coordinates::verbose = no</div><div class="gmail_default" style="font-size:large">552,553c552,553</div><div class="gmail_default" style="font-size:large">< SphericalSurface::maxntheta = 66</div><div class="gmail_default" style="font-size:large">< SphericalSurface::maxnphi = 124</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> SphericalSurface::maxntheta = 161</div><div class="gmail_default" style="font-size:large">> SphericalSurface::maxnphi = 320</div><div class="gmail_default" style="font-size:large">559,560c559,560</div><div class="gmail_default" style="font-size:large">< SphericalSurface::ntheta [2] = 41</div><div class="gmail_default" style="font-size:large">< SphericalSurface::nphi [2] = 80</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> SphericalSurface::ntheta [2] = 161</div><div class="gmail_default" style="font-size:large">> SphericalSurface::nphi [2] = 320</div><div class="gmail_default" style="font-size:large">565,566c565,566</div><div class="gmail_default" style="font-size:large">< SphericalSurface::ntheta [3] = 41</div><div class="gmail_default" style="font-size:large">< SphericalSurface::nphi [3] = 80</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> SphericalSurface::ntheta [3] = 161</div><div class="gmail_default" style="font-size:large">> SphericalSurface::nphi [3] = 320</div><div class="gmail_default" style="font-size:large">571,572c571,572</div><div class="gmail_default" style="font-size:large">< SphericalSurface::ntheta [4] = 41</div><div class="gmail_default" style="font-size:large">< SphericalSurface::nphi [4] = 80</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> SphericalSurface::ntheta [4] = 161</div><div class="gmail_default" style="font-size:large">> SphericalSurface::nphi [4] = 320</div><div class="gmail_default" style="font-size:large">633,634c633,638</div><div class="gmail_default" style="font-size:large">< IOScalar::outScalar_reductions = "minimum maximum average"</div><div class="gmail_default" style="font-size:large">< IOScalar::outScalar_vars = "SystemStatistics::process_memory_mb"</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> IOScalar::outScalar_reductions = "minimum maximum average norm1 norm2"</div><div class="gmail_default" style="font-size:large">> IOScalar::outScalar_vars = "</div><div class="gmail_default" style="font-size:large">> SystemStatistics::process_memory_mb</div><div class="gmail_default" style="font-size:large">> ML_ADMConstraints::ML_Ham</div><div class="gmail_default" style="font-size:large">> ML_ADMConstraints::ML_mom</div><div class="gmail_default" style="font-size:large">> "</div><div class="gmail_default" style="font-size:large">670c674</div><div class="gmail_default" style="font-size:large">< IOHDF5::out2D_every = $out2d_every</div><div class="gmail_default" style="font-size:large">---</div><div class="gmail_default" style="font-size:large">> IOHDF5::out2D_every = 0</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">Thank You</div><div class="gmail_default" style="font-size:large">Best Regards</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">---------------------------</div><div class="gmail_default" style="font-size:large"><br></div><div class="gmail_default" style="font-size:large">Yu Liu</div><div class="gmail_default" style="font-size:large">PhD Student</div><div class="gmail_default" style="font-size:large">Department of Astronomy</div><div class="gmail_default" style="font-size:large">Huazhong University of Science and Technology</div></div></div></div></div></div></div></div></div></div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br><a href="http://www.perimeterinstitute.ca/personal/eschnetter/" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a></div><div><br></div></div></div>