# AceFEM: Manipulation of SMTData[“MatrixGlobal”] after building but before solving

I want to manipulate the global stiffness matrix before I solve the system of equations. Unfortunately, the command SMTNewtonIteration[] builds up the global matrix and the global vector and solve the system of equations right away. Perhaps there are subfunctions called in SMTNewtonIteration which are not documented so far but can be adressed.

• Assembly of the stiffness matrix and load vector and solving the system of equations is done in "WinDriver" (written in C), so I think it is not possible to interfere with this procedure from Mathematica. But you can influence the global stiffness matrix indirectly by manipulating analysis data base structures, such as SMTNodeData. – Pinti Nov 22 '17 at 9:50