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Michal

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  1. PEST, SVD and SVD-assist

    Hi Jonas, If you try to generate random parameter values with this utility you have to decide how to describe the variability in the generated values. If you choose, that random values should obey (log)normal distribution you must specify its properties for each ajustable parameter (e.g. uncertainty of that parameter). This is done by specifing uncertainty file (see section 2.5 in PEST manual part II). Within this file uncertainties can be supplied on a parameter-by-parameter basis; alternatively one or a number of parameter covariance matrices can be supplied. If you want to avoid all this, try selecting (log)uniform distribution for the random values. Then you should be able to generate the uniformly distributed values without any problems. Hope it makes sense
  2. PEST Variables - Drain Conductance

    Hi Bruce, you may try to make one parameter adjustable (parent) and the rest in the basin tied to the parent. Relevant part from PEST manual: Or, alternatively, you could include the ratio between the pertinent parameters as prior information and adjust its weight accordingly. This way it would still be treated individualy, but the solution would tend to respect the parameter ratios. It is also also possible, that the contribution to total phi for drain observation group is too low, so it is invisible for the inversion proces. You may try to look at it in the case.rec file. It could be resolved by adjusting the weights for the observation groups. There is a nice utility form the PEST suit, that can help to balance this, its called PWTADJ1.
  3. PEST, SVD and SVD-assist

    If it is the case, that there is a bug in gms, so that it does not perform the final model run with the best parameter values stored in the case.bpa you would probably have to move the entire analysis out of GMS. I would suggest you to look at http://www.pesthomepage.org/. There you will find some guidelines on how to formulate the problem for the NSMC analysis to get the desired results. The usage of parrep utility is prety simple, it is command line utility, so since it is in your environment PATH variable you can run it from CMD: parrep parfile.bpa case_orig.pst case_new.pst The common framework for any NSMC analysis would be to manualy generate random parameter sets with the randpar utility then to project these sets into the solution space using pnulpar. Then runing PEST for each projected parameter set with 1 or 2 optimisation iteration to account for model nonlinearities and colect the best parameter values (.bpa files). Finaly you may run the model with these parameter sets to collect the predictions of interest.
  4. PEST, SVD and SVD-assist

    Hello Jonas, from my humble opinion it looks like PEST is doing its job well. It decreases Phi to 63.5% and finish optimisation after one iteration since NOPTMAX is set to 1.Which is probably correct if you try to do NSMC analysis. The reason it does not load solution into GMS may be a GMS glitch. What I think is happening, when PEST is run using svd-assisted inversion it does not carry the final model run using the best parameter values. As is described in the manual to PEST, it is encouraged for the user to do it him/herself using the PARREP utility and setting NOPTMAX to 0 in the PEST control file. So I am guesing that GMS does not do this for you. It would be best if someone from the GMS devs looked into it. Kind Regards Michal
  5. MT3D-NaCl barrier tessting

    Helo, it is hard to say without seeing the model. Could you be more specific in what do you mean by "nothing happens"? Do you mean like, the tracer concentration is zero everywhere through the simulation? First look at the mt3dms list file (case.out) and make sure, that the simulation ended without any errors. Then I would suggest to look at Output control in the basic transport package and make sure it is set properly, so MT3d is writing the concentration binary arrays at correct times. Also try to look at the model cell containing the injection well via sources/sinks dialog and check, that there is associated concentration with it.
  6. Dry cells

    There should be no obstacles in inactivating inner area of a single layer model using IBOUND. See the attached image.
  7. Coordinate Significant Figures

    Is each head observation in the *.hob file maped to the unique cell (IJK) and stress period? Athought it shouldn't matter if the observation's coordinates/times are not identical due to the offset variables (TOFFSET, ROF, COF), I can imagine certain confusion if multiple observation are defined for the same cell and stress period when using PEST.
  8. Hi It would be a nice feature to be able to display piezometric water level of a specifed layer(s) in a cross sectional view (row or column view) in adition to the free water table already implemented. I guess it would be suffictient to add one additinal curve to display and an option to specify from which layer the heads should be extracted. Clipping of the contours could remain as it is - using water table if water table is switched On or the second curve if water table is Off. Thx Michal
  9. constant concentration and source/sink

    Hi speedy, it seems you need to enable the MT3DMS SSM package to enable the mixing of fluid coming from the constant conc. BCs. I would try to enable SSM and set ICBUND to -1. It should work then. Hope it helps. Michal
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