Hiptmair–Xu preconditioner

The Hiptmair–Xu preconditioner is a mathematical tool used to improve the convergence of iterative methods for solving linear systems that arise from discretized partial differential equations (PDEs). It is particularly useful for problems governed by elliptic PDEs, including those that result from finite element discretizations. The preconditioner is named after its developers, who introduced it to address the challenges associated with solving large, sparse systems of equations.