1. But

Remove Lagrange equations from a matrix that has them.

This command is experimental. It is primarily intended to produce « Lagrange-free » matrices for the modal calculation operator (CALC_MODES).

Notes:

• To eliminate the Lagrange equations, we have to eliminate certain physical degrees of freedom (we eliminate a physical degree of freedom for each linear relationship if the relationships are not redundant).

• If a modal calculation is done with « reduced » matrices, the calculated modes must be returned to the original degrees of freedom using the REST_GENE_PHYS command.

Produces a matr_asse_elim_r data structure that can only be used in CALC_MODES.