###################### # GENERAL PARAMETERS # ###################### # Plummer softening parameter (can be even 0) eps = 1E-4 # End time of the calculation t_end = 1 # Interval of snapshot files output dt_disk = 0.125 # Interval for the energy control output (contr.dat) dt_contr = 0.125 # Interval for SMBH output (bh.dat, bh_neighbors.dat, and bh_inf.dat) dt_bh = 0.125 # Parameter for timestep determination eta = 0.01 # Name of the input file; use "data.con" in most cases [default: data.con] #input_file_name = data.con # Number of devices (GRAPEs or GPUs per node) [default: 0] # By default, each MPI process will attempt to bind to one device. To change # this behaviour, set the value to the number of available devices in the # system. For example, if from some reason you want to run multiple MPI # processes on a machine with a single device, set the value to 1 and use the # mpirun utility (or whatever is used in your job scheduler) to launch as many # processes as you like. #devices_per_node = 1 ########## # OUTPUT # ########## # Whether to use HDF5 format for snapshot and restart; regular ASCII snapshorts # are saved if false [default: false] #output_hdf5 = true # If using HDF5 output, use double precision or not [default: true] Consider # setting to false to save disk space. Restart file is always saved in double # precision. #output_hdf5_double_precision = true # If using ASCII output, the number of digits after the decimal point [default: 10] # Restart file is saved with 16 digits after the decimal point. #output_ascii_precision = 6 # Extra output: optionally save potential, acceleration and jerk in snapshot # files [default: 0] # This is a number between 0 and 7 that encodes the output options in the # following way: # [value] = [save jerk]*4 + [save acceleration]*2 + [save potential] # Example: choose 5 if it is needed to save the jerk and the potential, but not # the acceleration for some reason. # Currently implemented in HDF5 output only. #output_extra_mode = 7 # Whether to output a warning on the screen when the minimum time step is # encountered. [default: false] #dt_min_warning = false #################### # EXTERNAL GRAVITY # #################### # Remember that external gravity models are applied at the same coordinate # system as the particles. If the idea is to simulate a globular cluster # orbiting in an external field, be sure to set the initial conditions # appropriately (applying a shift to the coordinates and velocities). # Whether the parameters for the external gravitational field given below are in # physical units or Hénon units. If true, the system used is {kiloparsec, solar # mass, kilometre per second} [default: false] #ext_units_physical = true # If Physical units were selected, specify the simulation's unit mass (is solar # masses) and unit lenght (in parsec; not kiloparsec) # TODO: add the option to normalize using other units. #unit_mass = 4E5 # MSun #unit_length = 15 # pc # The bulge is a Plummer potential with the following total mass and radius. #ext_m_bulge = 5E9 # MSun #ext_b_bulge = 1.9 # kpc # The disk is a Miyamoto-Nagai potential with the following total mass, scale # length, and scale height #ext_m_disk = 6.8E10 # MSun #ext_a_disk = 3.00 # kpc #ext_b_disk = 0.28 # kpc # This halo option is yet another Plummer potential with the following total # mass and radius. #ext_m_halo_plummer = 8E11 # MSun #ext_b_halo_plummer = 245 # kpc # This halo option is a logarithmic potential with the following velocity and # radius parameters. #ext_log_halo_v = 240 # km/s #ext_log_halo_r = 1 # kpc # This is a spherical Dehnen model. #ext_dehnen_m = 1E11 # MSun #ext_dehnen_r = 2 # kpc #ext_dehnen_gamma = 0.5 ################################### # LIVE SUPERMASSIVE BLACK HOLE(S) # ################################### # There is special treatment for particles representing supermassive black holes # (SMBHs): they are integrated at every time step, they can have custom # softening in SMBH-SMBH interactions, and post Newtonian terms can be added to # the gravity. # The number of SMBH particles. Can be 0 (no SMBH), 1, or 2. [default: 0] #live_smbh_count = 2 # Custom softening length for SMBH-SMBH interactions (can also be zero). If # non-negative, the custom softening is applied. [default: -1] #live_smbh_custom_eps = 0 #TODO this is actually related only to BINARY smbh! # Output additional diagnostics about live SMBHs. [default: false] #live_smbh_output = true # Output additional diagnostics about the SMBH's (or SMBHs') nearest neighbours # (number could be set as shown below). [default: false] #live_smbh_neighbor_output = true # Number of nearest neighbours to the SMBH (or SMBHs) to include in output. [default: 10] #live_smbh_neighbor_number = 10 ################################## # BINARY SUPERMASSIVE BLACK HOLE # ################################## # The following parameters can be set when live_smbh_count is 2. # Output additional diagnostics about the sphere of influence (size could be set # as shown below). [default: false] #binary_smbh_influence_sphere_output = true # The influence sphere is centred at the binary SMBH's centre of mass, and its # radius is the semi-major axis of the binary times the factor below. [default: 10] #binary_smbh_influence_radius_factor = 3.162277660168379497918067e+03 # Add post Newtonian terms to SMBH-SMBH gravity. [default: false] #binary_smbh_pn = true # A mask array (zeros and ones) determining whether or not to use specific # post-Newtonian terms. # The elements represent {Newtonian, 1, 2, 2.5, 3, 3.5, spin} # Note: the first element in the array has no effect, the Newtonian force is # always included. #pn_usage = {1, 1, 1, 1, 0, 0, 0} # The speed of light in N-body units #pn_c = 477.12 # The spin vectors of the two SMBHs. Only define these if the last component of # pn_usage is set to one. #smbh1_spin = {0, 0, 1} #smbh2_spin = {0, 0, 1} ############### # HYBRID CODE # ############### # The hybridization with the SCF code is enabled if the ETICS preprocessor flag # is defined in the when compiling. # Time intervals to calculate the SCF series expansion. dt_scf = 0.015625 # Name of the mask file for GRAPite [default: grapite.mask] #grapite_mask_file_name = grapite.mask # Whether to write to disk a list of SCF coefficients at every dt_disk. [default: false] #etics_dump_coeffs = true # Whether to use an alternative procedure for active particle search that is # available in the GRAPite library. This requires the number of particles in # each MPI process to be exactly divisible by 32. This can substantially # accelerate the calculation in some circumstances [default: false] #grapite_active_search = true # If the number of active particles in a particular bunch is bigger than this # threshold, then the execution is on the GPU, otherwise on the CPU. When the # active bunch is small, the overhead of calculating the SCF gravity on the GPU # makes the operation more expensive than if it is done on the CPU. [default: 32] #grapite_dev_exec_threshold = 512 # TODO ######## # etics dump mode # scaling parameter override #################################### # Negative powers of two # #################################### # -1 1/2 0.5 # # -2 1/4 0.25 # # -3 1/8 0.125 # # -4 1/16 0.0625 # # -5 1/32 0.03125 # # -6 1/64 0.015625 # # -7 1/128 0.0078125 # # -8 1/256 0.00390625 # # -9 1/512 0.001953125 # # -10 1/1024 0.0009765625 # # -11 1/2048 0.00048828125 # # -12 1/4096 0.000244140625 # # -13 1/8192 0.0001220703125 # # -14 1/16384 0.00006103515625 # # -15 1/32768 0.000030517578125 # # -16 1/65536 0.0000152587890625 # ####################################