ansys.mapdl.core.Mapdl.eigen#

Mapdl.eigen(kmatrix='', mmatrix='', cmatrix='', evals='', evects='', **kwargs)#

Performs a modal solution with unsymmetric or damping matrices.

Mechanical APDL Command: *EIGEN

Parameters:
kmatrixstr

Name of the stiffness matrix. May be a real or complex-valued matrix.

mmatrixstr

Name of the mass matrix.

cmatrixstr

Name of the damping matrix (used only for modopt,DAMP).

evalsstr

Name of the output eigenvalues vector. It will be an m -long vec vector of complex values, where m is the number of eigenvalues requested ( modopt ).

evectsstr

Name of the output eigenvector matrix. It will be a n x m dmat (dense) matrix of complex values, where n is the size of the matrix and m is the number of eigenvalues requested ( modopt ).

Notes

Warning

This function contains specificities regarding the argument definitions. Please refer to the command documentation for further explanations.

Argument Descriptions

  • kmatrix : str - Name of the stiffness matrix. May be a real or complex-valued matrix.

  • mmatrix : str - Name of the mass matrix.

  • cmatrix : str - Name of the damping matrix (used only for modopt,DAMP).

  • evals : str - Name of the output eigenvalues vector. It will be an m -long vec vector of complex values, where m is the number of eigenvalues requested ( modopt ).

  • evects : str - Name of the output eigenvector matrix. It will be a n x m dmat (dense) matrix of complex values, where n is the size of the matrix and m is the number of eigenvalues requested ( modopt ).

Use the command antype,MODAL and the modopt command to specify the modal solution options. Only modopt ,DAMP, modopt,UNSYM, modopt,LANB, and modopt,SUBSP are supported.

eigen with Block Lanczos (LANB) only supports sparse matrices. Distributed-Memory Parallel (DMP) Restriction This command is not supported in a DMP solution.