rmf_create_nwt creates an RMODFLOW nwt object.
rmf_create_nwt( headtol = 0.001, fluxtol = 500, maxiterout = 100, thickfact = 1e-05, linmeth = 2, iprnwt = 0, ibotav = 0, options = "MODERATE", continue = TRUE, 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 )
| 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 |
| continue | logical; should the model solve a subsequent time step after it fails to converge ? Defaults to TRUE. |
| 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 |
| 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 |
| ilumethod | read if |
| levfill | read if |
| stoptol | read if |
| msdr | read if |
| iacl | read if |
| norder | read if |
| level | read if |
| north | read if |
| iredsys | read if |
| rrctols | read if |
| idroptol | read if |
| epsrn | read if |
| hclosexmd | read if |
| mxiterxmd | read if |
Object of class nwt
the option keyword controls the default values for input arguments dbdtheta - mxiterxmd. If option = "SPECIFIED", the user specifies the values.
If option = "SIMPLE", default values will be defined by NWT that work well for nearly linear models. If option =" MODERATE", default input values will be defined by NWT that work well for moderately nonlinear models.
If option = "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 option = "MODERATE".
If ILUMETHODE = 1, ILU with drop toleance 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.
nwt must be used with the Upstream Weighting flow package. See also rmf_create_upw.
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.