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Is there a linear system solver in PETSc?
In PETSc there are only iterative methods. We will show how to achieve direct methods later. The default linear system solver in PETSc is fully parallel, and will work on many linear systems, but there are many settings and customizations to tailor the solver to your specific problem.
How to create a KSP object in PETSc?
First we create a KSP object, which contains the coefficient matrix, and various parameters such as the desired accuracy, as well as method specific parameters: Routine reference: KSPCreate C: PetscErrorCode KSPCreate(MPI_Comm comm,KSP *v); Python: ksp = PETSc.KSP() ksp.create() # or: ksp = PETSc.KSP().create()
Which is the most important activity in PETSc?
Probably the most important activity in PETSc is solving a linear system. This is done through a solver object: an object of the class KSP . (This stands for Krylov SPace solver.) The solution routine KSPSolve takes a matrix and a right-hand-side and gives a solution; however, before you can call this some amount of setup is needed.
What are the operators of the kspsetoperatorscall?
The KSPSetOperatorscall takes two operators: one is the actual coefficient matrix, and the second the one that the preconditioner is derived from. In some cases it makes sense to specify a different matrix here. (You can retrieve the operators with KSPGetOperators.)
Which is better Petsc or a simple subroutine library?
PETSc is a sophisticated set of software tools; as such, for some users it initially has a much steeper learning curve than a simple subroutine library.
Which is the manual for the use of PETSc?
PETSc 3.7 January 1, 2017 Abstract: This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers.
Why is the KSP object the heart of PETSc?
The KSP object is the heart of PETSc, because it provides uniform and efficient access to all of the package’s linear system solvers, including parallel and sequential, direct and iterative. KSP is intended for solving systems of the form