rmf_create_nwt: Create an 'RMODFLOW' nwt object

In rogiersbart/RMODFLOW: Pre- and post-processing of MODFLOW files

Create an RMODFLOW nwt object

Description

rmf_create_nwt creates an RMODFLOW nwt object.

Usage

rmf_create_nwt(
  headtol = 0.001,
  fluxtol = 500,
  maxiterout = 100,
  thickfact = 1e-05,
  linmeth = 2,
  iprnwt = 0,
  ibotav = 0,
  options = "MODERATE",
  continue = FALSE,
  dbdtheta = 0.7,
  dbdkappa = 0.001,
  dbdgamma = 0,
  momfact = 0.1,
  backflag = 0,
  maxbackiter = 30,
  backtol = 2,
  backreduce = 0.99,
  maxitinner = 50,
  ilumethod = 2,
  levfill = 1,
  stoptol = 1e-10,
  msdr = 10,
  iacl = 2,
  norder = 1,
  level = 1,
  north = 2,
  iredsys = 0,
  rrctols = 0,
  idroptol = 1,
  epsrn = 0.001,
  hclosexmd = 1e-04,
  mxiterxmd = 50
)

Arguments

headtol	maximum head change between outer iterations for reaching convergence
fluxtol	maximum root-mean-squared flux difference between outer iterations for reaching convergence
maxiterout	maximum number of outer iterations allowed
thickfact	portion of cell thickness used for smoothly adjusting storage and conductance values to zero
linmeth	flag indicating if the GMRES (1) matrix solver or the XMD (2) matrix solver will be used
iprnwt	flag indicating if information about solver convergence is printed to the listing file
ibotav	logical; indicating whether corrections are made to groundwater head relative to the cell-bottom altitude if the cell is surrounded by dewatered cells.
options	character vector; possible values include "SPECIFIED", "SIMPLE", "MODERATE" and "COMPLEX". See details for more information.
continue	logical; should the model solve a subsequent time step after it fails to converge ? Defaults to FALSE.
dbdtheta	coefficient used to reduce the weight applied to the head change between nonlinear iterations
dbdkappa	coefficient used to increase the weight applied to the ead change between nonlinear iteraions
dbdgamma	factor used to weight the head change gor iterations n-1 and n
momfact	momentum coefficient
backflag	flag used to specify whether residual control will be used. A value of 1 indicates residual control is active, a value of 0 indicates it's inactive.
maxbackiter	is the maximum number of reductions in the head change between nonlinear iterations
backtol	proportional decrease in the root-mean-squared error of the groundwater-flow equation used to determine if residual control is required at the end of a nonlinear iteration
backreduce	reduction factor used for residual control that reduces head change between nonlinear iterations
maxitinner	read if LINMETHD = 1 & options = "SPECIFIED"; maximum number of iterations for the linear solution
ilumethod	read if LINMETHD = 1 & options = "SPECIFIED"; index for selection of the method for incomplete factorization (ILU) used as a preconditioner. See details.
levfill	read if LINMETHD = 1 & options = "SPECIFIED"; fill limit for ILUMETHOD = 1 and level of fill for ILUMETHOD = 2.
stoptol	read if LINMETHD = 1 & options = "SPECIFIED"; tolerance for convergence of the linear solver.
msdr	read if LINMETHD = 1 & options = "SPECIFIED"; number of iterations between restarts of the GMRES solver.
iacl	read if LINMETHD = 2 & options = "SPECIFIED"; flag for the acceleration method: 0 = conjugate gradient; 1 = ORTHOMIN, 2 = Bi-CGSTAB
norder	read if LINMETHD = 2 & options = "SPECIFIED"; flag for the scheme of ordering the unknowns; 0 = original ordering, 1 = RCM ordering; 2 = Minimum degree ordering
level	read if LINMETHD = 2 & options = "SPECIFIED"; level of fill for incomplte LU factorization
north	read if LINMETHD = 2 & options = "SPECIFIED"; number of orthogonalization for the ORTHOMIN acceleration scheme. Should equal 2 for the other acceleration methods
iredsys	read if LINMETHD = 2 & options = "SPECIFIED"; flag for applying reduced system preconditioning: 1 = apply; 0 = do not apply
rrctols	read if LINMETHD = 2 & options = "SPECIFIED"; residual reduction-convergence criteria
idroptol	read if LINMETHD = 2 & options = "SPECIFIED"; flag for using drop tolerance in the preconditioning
epsrn	read if LINMETHD = 2 & options = "SPECIFIED"; drop tolerance for preconditioning
hclosexmd	read if LINMETHD = 2 & options = "SPECIFIED"; head closure criteria for inner (linear) iteraions
mxiterxmd	read if LINMETHD = 2 & options = "SPECIFIED"; maximum number of iteraions for the linear solution

Details

the options keyword controls the default values for input arguments dbdtheta - mxiterxmd. If options = "SPECIFIED", the user specifies the values. If options = "SIMPLE", default values will be defined by NWT that work well for nearly linear models. If options =" MODERATE", default input values will be defined by NWT that work well for moderately nonlinear models. If options = "COMPLEX", default values will be defined by NWT that work well for highly nonlinear models. See the MODFLOW-NWT manual for details on these values. Default values for dbdtheta - mxiterxmd are set to those used when options = "MODERATE".

If ILUMETHODE = 1, ILU with drop tolerance and fill limit is used. If ILUMETHOD = 2, ILU(k), Order k incomplete LU factorization is used. See the MODFLOW-NWT and Kipp et al. (2008) for details.

Value

Object of class nwt

Note

nwt must be used with the Upstream Weighting flow package. See also rmf_create_upw.

References

Kipp, K.L., Jr., Hsieh, P.A. & Charlton, S.R. 2008, Guide to the revised groundwater flow and heat transport simulator; HYDROTERM - Version 3: U.S. Geological Survey Techniques and Methods 6-A25, 160 p.

See Also

rmf_read_nwt, rmf_write_nwt and https://water.usgs.gov/ogw/modflow-nwt/MODFLOW-NWT-Guide/

rogiersbart/RMODFLOW documentation built on Jan. 14, 2023, 4:21 a.m.