I am trying to figure out which solver (Fortran) will be able to calculate eigenvalues for a matrix that has been augmented with Lagrange multipliers.
Basically I have a FEM model with 20node solids and 4node plates that are coupled with Lagrange multies in a inhouse FE program. I have been using the Lapack DSPGVX subroutine in Fortran 90 with my other models but now with this coupling I am not able to because of the singularity of the matrix.
Anyone with some words if advice would be of great help...
Basically I have a FEM model with 20node solids and 4node plates that are coupled with Lagrange multies in a inhouse FE program. I have been using the Lapack DSPGVX subroutine in Fortran 90 with my other models but now with this coupling I am not able to because of the singularity of the matrix.
Anyone with some words if advice would be of great help...