260 lines
10 KiB
Text
260 lines
10 KiB
Text
######################
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# GENERAL PARAMETERS #
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######################
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# Plummer softening parameter (can be even 0)
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eps = 1E-4
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# End time of the calculation
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t_end = 1
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# Interval of snapshot files output
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dt_disk = 0.125
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# Interval for the energy control output (contr.dat)
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dt_contr = 0.125
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# Interval for SMBH output (bh.dat, bh_neighbors.dat, and bh_inf.dat)
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dt_bh = 0.125
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# Parameter for timestep determination
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eta = 0.01
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# Name of the input file; use "data.con" in most cases [default: data.con]
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#input_file_name = data.con
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# Number of devices (GRAPEs or GPUs per node) [default: 0]
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# By default, each MPI process will attempt to bind to one device. To change
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# this behaviour, set the value to the number of available devices in the
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# system. For example, if from some reason you want to run multiple MPI
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# processes on a machine with a single device, set the value to 1 and use the
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# mpirun utility (or whatever is used in your job scheduler) to launch as many
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# processes as you like.
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devices_per_node = 1
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# The power of 2 of the maximum timestep. For example, if dt_max_power=-3 and
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# the adaptive timestep algotirhm suggests anything bigger than 0.125, the
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# timestep will be 0.125. If the 2^dt_max_power > dt_contr, the maximum timestep
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# is dt_contr. [default: -3]
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#dt_max_power = -3
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# The power of 2 of the minimum timestep. [default: -36]
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#dt_min_power = -36
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# Eta correction factor for the first step (the timestep will be calculated with
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# eta divided by eta_s_corr) [default: 4]
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#eta_s_corr = 4.0
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# Eta correction factor for the black holes (the timestep for the black holes
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# will be calculated with eta divided by eta_bh_corr). [default: 4]
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#eta_bh_corr = 4.0
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##########
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# OUTPUT #
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##########
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# Whether to use HDF5 format for snapshot and restart; regular ASCII snapshorts
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# are saved if false [default: false]
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#output_hdf5 = true
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# If using HDF5 output, use double precision or not [default: true] Consider
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# setting to false to save disk space. Restart file is always saved in double
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# precision.
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#output_hdf5_double_precision = true
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# If using ASCII output, the number of digits after the decimal point [default: 10]
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# Restart file is saved with 16 digits after the decimal point.
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#output_ascii_precision = 6
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# Extra output: optionally save potential, acceleration and jerk in snapshot
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# files [default: 0]
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# This is a number between 0 and 7 that encodes the output options in the
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# following way:
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# [value] = [save jerk]*4 + [save acceleration]*2 + [save potential]
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# Example: choose 5 if it is needed to save the jerk and the potential, but not
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# the acceleration for some reason.
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# Currently implemented in HDF5 output only.
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#output_extra_mode = 7
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# Whether to output a warning on the screen when the minimum time step is
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# encountered. [default: false]
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#dt_min_warning = false
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####################
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# EXTERNAL GRAVITY #
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####################
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# Remember that external gravity models are applied at the same coordinate
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# system as the particles. If the idea is to simulate a globular cluster
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# orbiting in an external field, be sure to set the initial conditions
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# appropriately (applying a shift to the coordinates and velocities).
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# Whether the parameters for the external gravitational field given below are in
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# physical units or Hénon units. If true, the system used is {kiloparsec, solar
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# mass, kilometre per second} [default: false]
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#ext_units_physical = true
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# If Physical units were selected, specify the simulation's unit mass (is solar
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# masses) and unit lenght (in parsec; not kiloparsec)
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# TODO: add the option to normalize using other units.
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#unit_mass = 4E5 # MSun
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#unit_length = 15 # pc
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# The bulge is a Plummer potential with the following total mass and radius.
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#ext_m_bulge = 5E9 # MSun
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#ext_b_bulge = 1.9 # kpc
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# The disk is a Miyamoto-Nagai potential with the following total mass, scale
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# length, and scale height
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#ext_m_disk = 6.8E10 # MSun
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#ext_a_disk = 3.00 # kpc
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#ext_b_disk = 0.28 # kpc
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# This halo option is yet another Plummer potential with the following total
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# mass and radius.
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#ext_m_halo_plummer = 8E11 # MSun
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#ext_b_halo_plummer = 245 # kpc
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# This halo option is a logarithmic potential with the following velocity and
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# radius parameters.
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#ext_log_halo_v = 240 # km/s
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#ext_log_halo_r = 1 # kpc
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# This is a spherical Dehnen model.
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#ext_dehnen_m = 1E11 # MSun
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#ext_dehnen_r = 2 # kpc
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#ext_dehnen_gamma = 0.5
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###################################
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# LIVE SUPERMASSIVE BLACK HOLE(S) #
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###################################
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# There is special treatment for particles representing supermassive black holes
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# (SMBHs): they are integrated at every time step, they can have custom
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# softening in SMBH-SMBH interactions, and post Newtonian terms can be added to
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# the gravity.
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# The number of SMBH particles. Can be 0 (no SMBH), 1, or 2. [default: 0]
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#live_smbh_count = 2
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# Custom softening length for SMBH-SMBH interactions (can also be zero). If
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# non-negative, the custom softening is applied. [default: -1]
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#live_smbh_custom_eps = 0
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#TODO this is actually related only to BINARY smbh!
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# Output additional diagnostics about live SMBHs. [default: false]
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#live_smbh_output = true
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# Output additional diagnostics about the SMBH's (or SMBHs') nearest neighbours
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# (number could be set as shown below). [default: false]
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#live_smbh_neighbor_output = true
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# Number of nearest neighbours to the SMBH (or SMBHs) to include in output. [default: 10]
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#live_smbh_neighbor_number = 10
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##################################
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# BINARY SUPERMASSIVE BLACK HOLE #
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##################################
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# The following parameters can be set when live_smbh_count is 2.
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# Output additional diagnostics about the sphere of influence (size could be set
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# as shown below). [default: false]
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#binary_smbh_influence_sphere_output = true
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# The influence sphere is centred at the binary SMBH's centre of mass, and its
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# radius is the semi-major axis of the binary times the factor below. [default: 10]
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#binary_smbh_influence_radius_factor = 3.162277660168379497918067e+03
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# Add post Newtonian terms to SMBH-SMBH gravity. [default: false]
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#binary_smbh_pn = true
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# A mask array (zeros and ones) determining whether or not to use specific
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# post-Newtonian terms.
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# The elements represent {Newtonian, 1, 2, 2.5, 3, 3.5, spin}
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# Note: the first element in the array has no effect, the Newtonian force is
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# always included.
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#pn_usage = {1, 1, 1, 1, 0, 0, 0}
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# The speed of light in N-body units
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#pn_c = 477.12
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# The spin vectors of the two SMBHs. Only define these if the last component of
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# pn_usage is set to one.
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#smbh1_spin = {0, 0, 1}
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#smbh2_spin = {0, 0, 1}
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###############
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# HYBRID CODE #
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###############
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# The hybridization with the SCF code is enabled if the ETICS preprocessor flag
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# is defined in the when compiling.
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# Time intervals to calculate the SCF series expansion.
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dt_scf = 0.015625
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# Name of the mask file for GRAPite [default: grapite.mask]
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#grapite_mask_file_name = grapite.mask
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# Whether to write to disk a list of SCF coefficients at every dt_disk. [default: false]
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#etics_dump_coeffs = true
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# Whether to use an alternative procedure for active particle search that is
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# available in the GRAPite library. This requires the number of particles in
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# each MPI process to be exactly divisible by 32. This can substantially
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# accelerate the calculation in some circumstances [default: false]
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#grapite_active_search = true
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# Custom softening length for SMBH-star interactions in the hybrid scheme only.
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# This value (can also be zero) is used in the direct gravity calculation
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# between SMBHs (tag=3) and both core (tag=0) and halo (tag=1) stars. If
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# negative, the Plummer softening parameter (`eps`) is used in these
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# interactions. Do not confuse with `live_smbh_custom_eps`, which is the
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# softening length for SMBH-SMBH interactions, and works both in the normal and
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# hybrid schemes. [default: -1]
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#grapite_smbh_star_eps = 1E-6
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# If the number of active particles in a particular bunch is bigger than this
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# threshold, then the execution is on the GPU, otherwise on the CPU. When the
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# active bunch is small, the overhead of calculating the SCF gravity on the GPU
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# makes the operation more expensive than if it is done on the CPU. [default: 32]
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#grapite_dev_exec_threshold = 512
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# TODO
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########
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# etics dump mode
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# scaling parameter override
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####################################
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# Negative powers of two #
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####################################
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# -1 1/2 0.5 #
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# -2 1/4 0.25 #
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# -3 1/8 0.125 #
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# -4 1/16 0.0625 #
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# -5 1/32 0.03125 #
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# -6 1/64 0.015625 #
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# -7 1/128 0.0078125 #
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# -8 1/256 0.00390625 #
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# -9 1/512 0.001953125 #
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# -10 1/1024 0.0009765625 #
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# -11 1/2048 0.00048828125 #
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# -12 1/4096 0.000244140625 #
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# -13 1/8192 0.0001220703125 #
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# -14 1/16384 0.00006103515625 #
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# -15 1/32768 0.000030517578125 #
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# -16 1/65536 0.0000152587890625 #
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####################################
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