step
Please refer to the specific type of steps for details.
For any steps available, a default asymmetric banded dense storage is used. This storage scheme fits most
problems. The LAPACK driver used is _gbsv()
. The main reason behind such a choice stems from two aspects.
- For 2D and 3D problems, most material models have asymmetric stiffness moduli. The global stiffness matrix is then asymmetric.
- If the problem shows softening behaviour, the stiffness matrix is not always positive definite, the symmetric solver fails to solve such a matrix.