Teko is a package for development and implementation of block preconditioners. This includes support for manipulation and setup of block operators. Furthermore tools exist to support decomposition of a fully coupled operator. Additionally, facilities that allow the construction of approximate inverse operators using the full complement of available preconditioners and solvers are available in Teko. Finally, a small number of generic block preconditioners has been implemented in Teko, including block Jacobi, and block Gauss-Seidel. For the Navier-Stokes equation, Teko has implementations of SIMPLE, PCD and LSC. For details on these methods see Stabilization and Scalable Block Preconditioning for the Navier-Stokes Equations and the references therein
The Taliban’s 80,000 troops have retaken Afghanistan with cities falling like dominos while the 300,000-strong government forces, better equipped and trained, mostly melted and surrendered with no will to fight. Why did it happen?