Thank you so much for you swift response. I am referring to the definition of the analysis engine parameters in the FEM module of the WE-UQ tool. They include "analysis", "integration", "algorithm", "convergence test", and "solver". But I don't see a constraint option. I just wonder how constraint equations are handled by the program, and whether or not I need to include the constraint command in my tcl file when I am uploading an analysis script?