GMS:PEST Dialog: Difference between revisions
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{{MODFLOW Links}} | {{MODFLOW Links}} | ||
{{Infobox Calibration}} | {{Infobox Calibration}} | ||
[[File:PEST ParameterEstimation. | [[File:PEST ParameterEstimation.png|thumb|550 px|The ''PEST'' parameter estimation dialog]] | ||
The ''PEST'' dialog (''MODFLOW'' | '''Parameter Estimation''') allows the editing of inverse modeling options that are specific to PEST. This dialog is available when ''Parameter Estimation'' option is chosen as the [[GMS:Global Options/Basic Package|''Run'' option]] in the [[GMS:Global Options/Basic Package|''Global Options\Basic Package'']] dialog. | The ''PEST'' dialog (''MODFLOW'' | '''Parameter Estimation''') allows the editing of inverse modeling options that are specific to PEST. This dialog is available when ''Parameter Estimation'' option is chosen as the [[GMS:Global Options/Basic Package|''Run'' option]] in the [[GMS:Global Options/Basic Package|''Global Options\Basic Package'']] dialog. | ||
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===Max number of relative parameter change iterations (NRELPAR); Relative parameter change criterion (RELPARSTP)=== | ===Max number of relative parameter change iterations (NRELPAR); Relative parameter change criterion (RELPARSTP)=== | ||
If the magnitude of the maximum relative parameter change between optimisation iterations is less than the ''Relative Parameter Change Criterion (RELPARSTP) over Max # of Relative Parameter Change | If the magnitude of the maximum relative parameter change between optimisation iterations is less than the ''Relative Parameter Change Criterion (RELPARSTP)'' over ''Max # of Relative Parameter Change Iteration (NRELPAR)'' successive iterations, PEST will cease execution. | ||
All adjustable parameters, whether they are relative-limited or factor-limited, are involved in the calculation of the maximum relative parameter change. RELPARSTP is a real variable for which a value of 0.01 is often suitable. NRELPAR is an integer variable; a value of 2 or 3 is normally satisfactory. | All adjustable parameters, whether they are relative-limited or factor-limited, are involved in the calculation of the maximum relative parameter change. RELPARSTP is a real variable for which a value of 0.01 is often suitable. NRELPAR is an integer variable; a value of 2 or 3 is normally satisfactory. | ||
Max relative parameter change per iteration | ===Max relative parameter change per iteration=== | ||
This (RELPARMAX) is the maximum relative change that a parameter is allowed to undergo between optimisation iterations. | This (RELPARMAX) is the maximum relative change that a parameter is allowed to undergo between optimisation iterations. | ||
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==SVD (Singular Value Decomposition)== | ==SVD (Singular Value Decomposition)== | ||
[[File:SVD Options.png|thumb| | [[File:SVD Options.png|thumb|230 px|The ''SVD Options'' dialog]] | ||
The ''Use SVD'' toggle is available to turn on the SVD functionality in PEST. For a more complete explanation of SVD, see the [http://gmsdocs.aquaveo.com/pest.pdf PEST manual] in section 8.4. The inputs to the SVD process can be edited by selecting the '''SVD Options''' button. | The ''Use SVD'' toggle is available to turn on the SVD functionality in PEST. For a more complete explanation of SVD, see the [http://gmsdocs.aquaveo.com/pest.pdf PEST manual] in section 8.4. The inputs to the SVD process can be edited by selecting the '''SVD Options''' button. | ||
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==SVD-Assist== | ==SVD-Assist== | ||
[[File:SVD-Assist Options.png|thumb| | [[File:SVD-Assist Options.png|thumb|260 px|The ''SVD-Assist Options'' dialog]] | ||
The ''Use SVD-Assist'' toggle turns on the SVD-Assist process for PEST. This process is particularly advantageous for models that have hundreds or thousands of parameters (such as pilot points). SVD-Assist involves 3 basic steps. | The ''Use SVD-Assist'' toggle turns on the SVD-Assist process for PEST. This process is particularly advantageous for models that have hundreds or thousands of parameters (such as pilot points). SVD-Assist involves 3 basic steps. | ||
#First, PEST runs MODFLOW once for every parameter in order to compute a matrix. This information is used to create super parameters that are combinations of the parameters originally specified. | #First, PEST runs MODFLOW once for every parameter in order to compute a matrix. This information is used to create super parameters that are combinations of the parameters originally specified. | ||
#Second, SVDAPREP is run to create a new PEST control file. The options for SVDAPREP are entered by selecting the '''SVD-Assist Options''' button. For more information on each of these options see the PEST manual in section 8.5.4.2. The most important option entered is the ''Specify # super param'' and this is set to ''No'' by default. When this option is set to ''No'', then the information written to the *.svd file will be used to specify the number of super parameters. | #Second, SVDAPREP is run to create a new PEST control file. The options for SVDAPREP are entered by selecting the '''SVD-Assist Options''' button. For more information on each of these options see the PEST manual in section 8.5.4.2. The most important option entered is the ''Specify # super param'' and this is set to ''No'' by default. When this option is set to ''No'', then the information written to the *.svd file will be used to specify the number of super parameters. | ||
#Third, PEST runs using the new control file written by SVDAPREP. This should result in significantly fewer model runs for each PEST iteration. This often results in an order of magnitude reduction in the number of runs required for each PEST iteration. | #Third, PEST runs using the new control file written by SVDAPREP. This should result in significantly fewer model runs for each PEST iteration. This often results in an order of magnitude reduction in the number of runs required for each PEST iteration. | ||
:'''''Note:''''' When PEST runs with SVD-Assist, it does not output sensitivities of individual parameters. Therefore there is not an option to view parameters a parameters sensitivity plot. | |||
==Tikhonov Regularization== | ==Tikhonov Regularization== | ||
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==See also== | ==See also== | ||
[[GMS:Model Calibration|Model Calibration]] | *[[GMS:Model Calibration|Model Calibration]] | ||
{{Navbox GMS}} | {{Navbox GMS}} | ||
