APDL Math automatically maintains APDL parameters corresponding to the size of every matrix and vector you create. The APDL parameter are created as follows:
For an example matrix named "MyMatrix", the APDL parameters MyMatrix_rowDim and MyMatrix_colDim are automatically created.
For matrices imported from the .full file, the APDL parameter MyMatrix_NUMDOF is automatically created, where NUMDOF is the number of degrees of freedom per node.
For an example vector named "MyVector", the APDL parameter MyVector_Dim is automatically created.
These APDL parameters are updated each time you manipulate these objects using APDL Math commands.