Solutions Obtained from Structurally Singular Models

Release 8.0 (or later) of GEMPACK can produce solutions which are obtained by modifying the equations of a model whose LHS Matrix is structurally singular. The number of equations modified is equal to the rank deficiency. The same number of variables have their values set to zero. When you load such a solution, AnalyseGE tells you the rank deficiency before showing you the TAB file.

If you select the menu item Structurally Singular Information under the View menu on the AnalyseGE form, you can see the names of the altered equations and of the variables whose values have been set to zero. [This menu item is only available if the solution you have loaded into AnalyseGE comes from modifying the equations of a model whose LHS Matrix is structurally singular.]

We produce such solutions in the hope that you will be able to use AnalyseGE to assist you in finding the cause of the singularity.

Because the solution shown is not the solution of the original model (but of modified equations), you should use care when looking at the solution.

For more details, see  the GEMPACK manual.

URL of this topic: www.copsmodels.com/webhelp/analysege/hc_structsingular.htm

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