SETTINGS

# This file lists all BOUT++ settings (with default values)
#
# File is divided into sections which can be in any order.
# Comments start with either a ';' or a '#'

NOUT = 1           # Number of outputs
TIMESTEP = 1.0     # Time between outputs
WALL_LIMIT = -1.0  # Wall clock limit in hours. -ve means no limit
archive = -1       # Number of outputs between restart archiving
                   # -ve means no archiving

grid = "data/bout.grd.pdb" # Grid file to use

ShiftXderivs = false   # Use shifted X derivatives
IncIntShear = false    # 
ShiftInitial = ShiftXderivs # Shift the initial condition
TwistShift = false     # Use Twist-Shift condition?
ShiftOrder = 0         # X shift order (1,4 or 0 = FFT)
TwistOrder = 0         # Twist-shift order (1,4 or 0 = FFT)

non_uniform = false    # Use corrections for non-uniform meshes

MZ = 65                # Number of points in Z (2^n + 1)
zperiod = 1            # How many periods in 2pi
                       # NOTE: Instead of zperiod, ZMIN and ZMAX
                       # can be specified in units of 2pi

MXG = 2                # # of X guard cells (change with care!)
MYG = 2                # # of Y guard cells (change with care!)

BoundaryOnCell = false # Location of boundary

StaggerGrids = false   # Use staggered grids

NXPE = 1               # Number of processors in X

dump_float = true      # Output floats to dump file
                       # (false -> doubles)

dump_format = "pdb"    # Data format for the dump files.
                       # for NetCDF, set to "cdl", "nc" or "ncdf"
restart_format = dump_format  # Format for restart files

[comms]

async = true           # Use asyncronous sends
group_nonblock = true  # Use non-blocking group communications

[fft]

fft_measure = true     # If using FFTW, perform tests to determine
                       # fastest method

[solver]

# NOTE: Some of these options only apply to some solvers

mudq = n3d*(MXSUB+2)
mldq = n3d*(MXSUB+2)
mukeep = 0
mlkeep = 0
ATOL = 1.0e-12
RTOL = 1.0e-5

use_precon = false   # If the physics solver specifies a preconditioner
                     # then use that, otherwise BBD is used

use_jacobian = false # If the physics solver specifies a Jacobian
                     # then use that. Otherwise a difference quotient
                     # method is used internally

precon_dimens = 50   # For BBD preconditioner
precon_tol = 1.0e-4  # For BBD

adams_moulton = false # Use Adams-Moulton method (default is BDF)
func_iter = false     # Functional iteration (default is Newton)

[laplace]

filter = 0.2    # Fraction of toroidal modes to filter out
low_mem = false # For parallel algorithm, use less memory
                # This is at the expense of communication overlap

use_pdd = false # Use the approximate Parallel Diagonally Dominant solver 

all_terms = false # Include all the extra terms in Delp2 and inversion

[ddx]

first = C4
second = C4
upwind = W3

[ddy]

first = C4
second = C4
upwind = W3

[ddz]

first = C4
second = C4
upwind = W3