Accessing Separate Parameter Values Used when Doing SSA wrt Parameters

How can I access the separate parameter values used when doing SSA with respect to parameters?

The SSA features of RunGEM described here require GEMPACK 10 or later.

When you use RunGEM or RunGTAP to do systematic sensitivity analysis (SSA) with respect to parameters, the model is solved several times, each time using different values of the parameters. These parameters may be held on one or several of the imput data files for the model. The software prepares new input data files for each of the solves.

If a logical data file has no parameters which are varying in the SSA you have specified, the software uses the original version of that data file. But if another logical data files contains values of parameters which are varying in the SSA you have specified, the software prepares and uses a new version of that data file for each of the SSA solves.

Normally these separate data files are deleted after each solve and you are not able to access them.

If you wish to access the data files prepared for SSA, you can do so by double clicking on the "Parameters to vary" label (it is usually green in colour) on the "Set up Parameter sensitiviy calculation" form you use to specify which parameters are varying and how they are varying.

You will know that you have clicked in the correct place when you see a dialog box asking "Keep separate SSA Parameter files?". [If you don't see this you have not double clicked in the expected place.]

Click YES and the software will tell you where these data files will be stored. [They are usually stored in a subdirectory SSA of the Output directory.]

When the SSA calculations are finished, you should be able to find the separate data files files. The names of these data files are of the form [logical-name]x.dat for solve number x (x=1,2,3,...) - for example, basedata1.dat. The logical-name is as in the TAB file and as in the Data part of the Model/Data page.

NOTE 31 July 2008. At present the ability to store these different parameters values is only available with RunGEM (and only with a very recent version of RunGEM), not with RunGTAP. If you need to do this, please download RunGEM following the instructions at the top of this page.

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