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, ViewSOL warns you of the rank deficiency before showing you the solution.

You have the option of seeing the names of the altered equations and of the variables whose values have been set to zero. These may 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, search in the GEMPACK manual for the subsection headed "Solving modified equations when LHS matrix is structurally singular".

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

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