petsc-3.3-p7 2013-05-11

KSPSolve

Solves linear system.

#include "petscksp.h" 
PetscErrorCode  KSPSolve(KSP ksp,Vec b,Vec x)

Collective on KSP

	ksp	- iterative context obtained from KSPCreate()
	b	- the right hand side vector
	x	- the solution (this may be the same vector as b, then b will be overwritten with answer)

	-ksp_compute_eigenvalues	- compute preconditioned operators eigenvalues
	-ksp_plot_eigenvalues	- plot the computed eigenvalues in an X-window
	-ksp_compute_eigenvalues_explicitly	- compute the eigenvalues by forming the dense operator and useing LAPACK
	-ksp_plot_eigenvalues_explicitly	- plot the explicitly computing eigenvalues
	-ksp_view_binary	- save matrix and right hand side that define linear system to the default binary viewer (can be read later with src/ksp/examples/tutorials/ex10.c for testing solvers)
	-ksp_converged_reason	- print reason for converged or diverged, also prints number of iterations
	-ksp_final_residual	- print 2-norm of true linear system residual at the end of the solution process
	-ksp_view	- print the ksp data structure at the end of the system solution

If one uses KSPSetDM() then x or b need not be passed. Use KSPGetSolution() to access the solution in this case.

The operator is specified with KSPSetOperators().

Call KSPGetConvergedReason() to determine if the solver converged or failed and why. The number of iterations can be obtained from KSPGetIterationNumber().

If using a direct method (e.g., via the KSP solver KSPPREONLY and a preconditioner such as PCLU/PCILU), then its=1. See KSPSetTolerances() and KSPDefaultConverged() for more details.

The routines KSPMonitorSet(), KSPComputeEigenvalues(), and KSPComputeEigenvaluesExplicitly() provide information on additional options to monitor convergence and print eigenvalue information.

KSP, solve, linear system