# GMS:DE4 Package

From XMS Wiki

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

MODFLOW | |
---|---|

Pre-processing | |

MODFLOW Commands | |

Building a MODFLOW Model | |

Map to MODFLOW | |

Calibration | |

Packages Supported in GMS | |

Saving a MODFLOW Simulation | |

Importing MODFLOW Files | |

Unsupported MODFLOW Features | |

Post-processing | |

MODFLOW Display Options | |

MODFLOW Post-Processing Viewing Options | |

Reading a MODFLOW Simulation | |

Tutorials | |

MODFLOW Tutorials | |

Packages | |

Flow: |
BCF6, HUF, LPF, UPW |

Solvers: |
SMS |

Other: |
UZF1 |

The DE4 package or Direct Solver is one of the solvers available for MODFLOW. It requires reading in a DE4 file. The *MODFLOW DE4 Solver* package dialog will show the variables in the DE4 file. Variables include:

*Comments (Text)*– Allows up to 199 characters.*Maximum number of iterations (ITMX)*– Per time step. Enter 1 for no interations.*Maximum number of upper equations (MXUP)*– Impacts the amount of memory used by the package. Prints the actual number of equations in the upper part when the package runs.*Maximum number of lower equations (MXLOW)*– Impacts the amount of memory used by the package. Prints the actual number of equations in the lower part when the package runs.*Maximum bandwidth (MXBW)*– Impacts the amount of memory used by the package. Prints the actual band width plus 1 when the package runs.*Frequency of change of coefficients in [A]*(IFREQ) – Affects the efficiency of solution. Can be 1,2, or 3.

- 1 = The flow equations are linear and that coefficients of simulated head for all stress terms are constant for all stress periods.
- 2 = The flow equations are linear, but coefficients of simulated head for some stress terms may change at the start of each stress period.
- 3 = A nonlinear flow equation is being solved, which means that some terms in [A] depend on simulated head.

*Print flag for convergence information per time step (MUTD4)*– Can be 0, 1, or 2.

- 0 = The number of iterations in the time step and the maximum head change each iteration are printed.
- 1 = Only the number of iterations in the time step is printed.
- 2 = No information is printed.

*Head change multiplier (ACCL)*– Normally this value is 1. A value greater than 1 may be useful for improving the rate of convergence when using external iteration to solve nonlinear problems.*Head change closure criterion (HCLOSE)*– Not used if not iterating, but a value must always be specified.*Interval for time step printing (IPRD4)*– Not used if not iterating, but a value must always be specified.

## DE4 File Format

FOR EACH SIMULATION 0. [#Text] 1. ITMX MXUP MXLOW MXBW 2. IFREQ MUTD4 ACCL HCLOSE IPRD4

Item 0 is optional—“#” must be in column 1. Item 0 can be repeated multiple times.

## See Also

- For more information on this solver, see page 84 of the USGS documentation.

GMS – Groundwater Modeling System | ||
---|---|---|

Modules: | 2D Grid • 2D Mesh • 2D Scatter Point • 3D Grid • 3D Mesh • 3D Scatter Point • Boreholes • GIS • Map • Solid • TINs • UGrids | |

Models: | FEFLOW • FEMWATER • MODAEM • MODFLOW • MODPATH • mod-PATH3DU • MT3DMS • MT3D-USGS • PEST • PHT3D • RT3D • SEAM3D • SEAWAT • SEEP2D • T-PROGS • ZONEBUDGET | |

Aquaveo |

Retrieved from "https://www.xmswiki.com/index.php?title=GMS:DE4_Package&oldid=130765"

Hidden category: