GMS:PCG Package: Difference between revisions

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The Preconditioned Conjugate Gradient Method (PCG) package is one of the [[GMS:MODFLOW Packages Supported in GMS#Solver Packages|solver packages]] for MODFLOW supported by GMS.
The Preconditioned Conjugate Gradient Method (PCG) package is one of the [[GMS:MODFLOW Packages Supported in GMS#Solver Packages|solver packages]] for MODFLOW supported by GMS.


===Maximum outer iterations===
''Maximum outer iterations''
This value is the maximum iterations, or calls to the solver.  For linear problems, this value can be 1, unless more than 50 inner iterations are required, when maximum outer iterations could be as large as 10.  For non linear problems, this values should be larger, but generally less than 100.  
<blockquote style="margin-top:0px; margin-bottom:0px;">
This value is the maximum iterations, or calls to the solver.  For linear problems, this value can be 1, unless more than 50 inner iterations are required, when maximum outer iterations could be as large as 10.  For non linear problems, this values should be larger, but generally less than 100.</blockquote>


===Maximum inner iterations===
''Maximum inner iterations''
<blockquote style="margin-top:0px; margin-bottom:0px;">
This value is the maximum number of iterations per call to the solver.  The default value is 50, and this is sufficient for most problems.
This value is the maximum number of iterations per call to the solver.  The default value is 50, and this is sufficient for most problems.
</blockquote>


===Matrix Preconditioning Method===
''Matrix Preconditioning Method''
Use this radio group to choose the matrix conditioning method.  The default is to use a modified incomplete cholesky method.
<blockquote style="margin-top:0px; margin-bottom:0px;">
Use this radio group to choose the matrix conditioning method.  The default is to use a modified incomplete cholesky method.</blockquote>


===Relaxation Parameter===
''Relaxation Parameter''
This value is used if the modified incomplete cholesky method is used.  Usually, this value is 1.0, but for some problems a value of 0.99, 0.98, or 0.97 will reduce the number of iterations required for convergence.
<blockquote style="margin-top:0px; margin-bottom:0px;">
This value is used if the modified incomplete cholesky method is used.  Usually, this value is 1.0, but for some problems a value of 0.99, 0.98, or 0.97 will reduce the number of iterations required for convergence.</blockquote>


===Head Change Criterion For Convergence===
''Head Change Criterion For Convergence''
When the maximum absolute value of head change from all cells during an iteration is less than or equal to the head change criterion, AND the residual change criterion is met, solver iteration stops.
<blockquote style="margin-top:0px; margin-bottom:0px;">
When the maximum absolute value of head change from all cells during an iteration is less than or equal to the head change criterion, AND the residual change criterion is met, solver iteration stops.</blockquote>


===Residual Change Criterion For Convergence===
''Residual Change Criterion For Convergence''
<blockquote style="margin-top:0px; margin-bottom:0px;">
When the maximum absolute value of residuals from all cells during an iteration is less than or equal to the residual change criterion, AND the head change criterion is met, solver iteration stops.
When the maximum absolute value of residuals from all cells during an iteration is less than or equal to the residual change criterion, AND the head change criterion is met, solver iteration stops.
</blockquote>


===Reset===
'''Reset'''
<blockquote style="margin-top:0px; margin-bottom:0px;">
This button will change all options to the default state.
This button will change all options to the default state.
 
</blockquote>
[[File:MODFLOW-PCG.png|thumb|none|left|400 px|The ''MODFLOW PCG Package'' dialog.]]
[[File:MODFLOW-PCG.png|thumb|none|left|400 px|The ''MODFLOW PCG Package'' dialog.]]


Revision as of 21:51, 31 October 2016

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
Run MODFLOW
Post-processing
MODFLOW Display Options
MODFLOW Post-Processing Viewing Options
Reading a MODFLOW Simulation
Tutorials
Packages
Flow: BCF6, HUF, LPF, UPW
Solvers:

DE4, GMG, NWT, PCG,

PCGN, LMG, SIP, SOR,

SMS
Other:

BAS6, BFH, CHD1, CLN,

DRN1, DRT1, EVT1, ETS1,

GAGE, GHB1, GNC, HFB1,

HUF, LAK3, MNW1, MNW2,

OUT1, RCH1, RIV1, SFR2,

STR1, SUB1, SWI2, WEL1,

UZF1
v • e

The Preconditioned Conjugate Gradient Method (PCG) package is one of the solver packages for MODFLOW supported by GMS.

Maximum outer iterations

This value is the maximum iterations, or calls to the solver. For linear problems, this value can be 1, unless more than 50 inner iterations are required, when maximum outer iterations could be as large as 10. For non linear problems, this values should be larger, but generally less than 100.

Maximum inner iterations

This value is the maximum number of iterations per call to the solver. The default value is 50, and this is sufficient for most problems.

Matrix Preconditioning Method

Use this radio group to choose the matrix conditioning method. The default is to use a modified incomplete cholesky method.

Relaxation Parameter

This value is used if the modified incomplete cholesky method is used. Usually, this value is 1.0, but for some problems a value of 0.99, 0.98, or 0.97 will reduce the number of iterations required for convergence.

Head Change Criterion For Convergence

When the maximum absolute value of head change from all cells during an iteration is less than or equal to the head change criterion, AND the residual change criterion is met, solver iteration stops.

Residual Change Criterion For Convergence

When the maximum absolute value of residuals from all cells during an iteration is less than or equal to the residual change criterion, AND the head change criterion is met, solver iteration stops.

Reset

This button will change all options to the default state.

The MODFLOW PCG Package dialog.


v • e
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