Hello Hon-ka,

please take a look at this email thread:

http://lists.einsteintoolkit.org/pipermail/users/2018-January/006030.html

where similar issues have been addressed. The group in Parma made their parameter files available for download.

The URL to the Parma server changed and is now:

https://einstein.pr.infn.it/gravity/Research/BNS2015.html

Yours, Roland

Dear all,

I encountered some problem while carrying out some binary neutron star simulations and would like to know if anyone can help me out.

I followed the BNS example on the site (nsnstohmns) but adopted the "Hybrid" eos for the BNS Meudon initial data generated with certain tabular nuclear models.

#####-----#####-----#####-----#####-----#####-----#####-----#####-----#####-----##### Problem 1:

I understand that I need to assign the following parameters accordingly, Meudon_Bin_NS::eos_table = "Hybrid" EOS_Omni::hybrid_gamma_th EOS_Omni::n_pieces EOS_Omni::hybrid_k0 EOS_Omni::hybrid_gamma[] EOS_Omni::hybrid_rho[]

but I am not sure whether it is correct to also set GRHydro::GRHydro_eos_table = "Hybrid" ? or should I set GRHydro::GRHydro_eos_table = "Ideal_Fluid" ?

In the BNS example nsnstohmns, despite using a polytropic BNS model, the parameter file shows GRHydro::GRHydro_eos_type = "General" instead of "Polytype" GRHydro::GRHydro_eos_table = "Ideal_Fluid" instead of "2D_Polytrope" What is the particular reason for this setting ??

#####-----#####-----#####-----#####-----#####-----#####-----#####-----#####-----##### Problem 2:

Here is one of the error I encountered.

WARNING level 1 from host emc4 process 0 in thorn CarpetLib, file /home/hkhui/Cactus/configs/sim/build/CarpetLib/dh.cc:161: -> /home/hkhui/Cactus/configs/sim/build/CarpetLib/dh.cc:837: [ml=0 rl=7 c=0] The following grid structure consistency check failed: Refinement prolongation: All points must have been received needrecv.empty() WARNING level 1 from host emc4 process 0 in thorn CarpetLib, file /home/hkhui/Cactus/configs/sim/build/CarpetLib/dh.cc:161: -> /home/hkhui/Cactus/configs/sim/build/CarpetLib/dh.cc:983: [ml=0 rl=7 c=0] The following grid structure consistency check failed: Synchronisation and boundary prolongation: All points must have been received needrecv.empty()

It seems this error is associated with the following settings in the parfile CoordBase::xmin = 0.00 CoordBase::ymin = -396.00 CoordBase::zmin = 0.00 CoordBase::xmax = +396.00 CoordBase::ymax = +396.00 CoordBase::zmax = +396.00 CoordBase::dx = 9.00 CoordBase::dy = 9.00 CoordBase::dz = 9.00 CarpetRegrid2::num_levels_1 = 7 CarpetRegrid2::position_x_1 = 15.1875 CarpetRegrid2::radius_1[1] =240.0 CarpetRegrid2::radius_1[2] =120.0 CarpetRegrid2::radius_1[3] = 60.0 CarpetRegrid2::radius_1[4] = 28.125 # nsnstohmns 26.125 CarpetRegrid2::radius_1[5] = 19.875 # nsnstohmns 17.875 CarpetRegrid2::radius_1[6] = 11.0 # nsnstohmns 13

The initial size of the stars of my model: Coordinate separation between the two stellar centers : 45 km Coordinate equatorial radius (phi=0) a1 = 10.16960419148 km Coordinate equatorial radius (phi=pi/2) a2 = 9.872118702179 km Coordinate equatorial radius (phi=pi): 10.19931065979 km Coordinate polar radius a3 = 9.925176860927 km

I used the nsnstohmns parfile while changing the eos part and the resolution only, for the set of par above, I set [5] and [6] so that they together cover the separation (19.875+11 M > 45km) and I set [4] so that this refinement region of the 1st star cover some region of the 2nd star. I would like to know if there is any rule for setting the AMR region (the radius par above), I varied these radius parameters and end up with either error about the grid structure (see above err message) or the c2p conversion error, but never been able to carry out simulation to merger. If the problem is not about the AMR region radius setting, what could be the problem?

#####-----#####-----#####-----#####-----#####-----#####-----#####-----#####-----##### Problem 3:

I have carried the BNS simulation with stars of slightly larger R initially with my nuclear eos, and adopted exactly the same parfile setting as nsnstohmns with Time::dtfac = 0.35, it happens that the NSTracker thorn loses track of the stars. The rho_max position suddenly moved so fast that I suspect the result is wrong. And the position of the star is not updated anymore after certain time step. What could cause such false result??

---

Iteration Time | *me_per_hour | GRHYDRO::dens | *ROBASE::rho | *::w_lorentz | *STRAINTS::H | *axrss_mb | | sum maximum | maximum | maximum | maximum | maximum

---

INFO (NSTracker): Found star at (15.1875,0.28125,0) 200 4.922 | 113.9376773 | 0.0001258 0.0027456 | 0.0011040 | 1.3729137 | 0.0031954 | 989 INFO (NSTracker): Found star at (15.1875,0.5625,0) 400 9.844 | 114.5209435 | 0.0001258 0.0026962 | 0.0011407 | 1.5612539 | 0.0050456 | 991 INFO (NSTracker): Found star at (15.1875,0.84375,0) 600 14.766 | 114.7115204 | 0.0001259 0.0014155 | 0.0006785 | 1.6008531 | 0.0038587 | 993 INFO (NSTracker): Found star at (15.1875,1.125,0) 620 15.258 | 114.1468585 | 0.0001259 0.0011319 | 0.0005486 | 1.6009425 | 0.0036545 | 1084 INFO (NSTracker): Found star at (14.9062,1.6875,0) 660 16.242 | 113.7788398 | 0.0001259 0.0007284 | 0.0003032 | 1.6088940 | 0.0033746 | 1084 INFO (NSTracker): Found star at (14.9062,1.96875,0) 668 16.439 | 113.6618707 | 0.0001259 0.0006774 | 0.0002687 | 1.6088572 | 0.0033143 | 1084 INFO (NSTracker): Found star at (14.625,1.96875,0) 672 16.537 | 113.4731182 | 0.0001259 0.0006559 | 0.0002538 | 1.6088969 | 0.0032825 | 1084 INFO (NSTracker): Found star at (14.625,2.25,0) 676 16.636 | 112.2718493 | 0.0001259 0.0006351 | 0.0002415 | 1.6090522 | 0.0032501 | 993 INFO (NSTracker): Found star at (14.625,2.53125,0) 684 16.833 | 112.1253398 | 0.0001259 0.0005958 | 0.0002184 | 1.6093073 | 0.0031844 | 993 INFO (NSTracker): Found star at (14.625,2.8125,0) 688 16.931 | 111.9626309 | 0.0001259 0.0005780 | 0.0002090 | 1.6111194 | 0.0031493 | 993

...

INFO (NSTracker): New star location not set (0.5625,-0.28125,0) because too far from old (13.7812,7.875,0). 884 21.755 | 99.6235324 | 0.0001259 0.0002227 | 0.0000792 | 1.9277784 | 0.0066220 | 1183 INFO (NSTracker): New star location not set (0.84375,0.28125,0) because too far from old (13.7812,7.875,0). 1004 24.708 | 99.9757198 | 0.0001259 0.0001761 | 0.0001082 | 2.0183873 | 0.0088739 | 1183 INFO (NSTracker): New star location not set (1.125,-0.5625,0) because too far from old (13.7812,7.875,0). 1008 24.806 | 100.0596083 | 0.0001259 0.0001782 | 0.0001092 | 2.0194414 | 0.0089929 | 1183

...

INFO (NSTracker): New star location not set (3.9375,-21.375,0) because too far from old (13.7812,7.875,0). 2244 55.223 | 99.3936843 | 0.0001258 0.0000634 | 0.0000347 | 2.5307425 | 0.0051844 | 1189

...

INFO (NSTracker): New star location not set (11.25,-45,33.75) because too far from old (13.7812,7.875,0). 4028 99.127 | 98.5126340 | 0.0001270 0.0000141 | 0.0000075 | 3.0658306 | 0.0034565 | 1190

#####-----#####-----#####-----#####-----#####-----#####-----#####-----#####-----#####

Any help will be greatly appreciated..

Yours, Hon-ka

-- Open WebMail Project (http://openwebmail.org)

---

Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users