krylov Module Reference

Implements the base abstract type for Krylov solvers plus helper types.

Data Types
interface	ksp_method
	Abstract interface for a Krylov method's solve routine. More...
interface	ksp_method_coupled
	Abstract interface for a Krylov method's coupled solve routine. More...
type	ksp_monitor_t
	Type for storing initial and final residuals in a Krylov solver. More...
type	ksp_t
	Base abstract type for a canonical Krylov method, solving \( Ax = f \). More...
interface	ksp_t_free
	Abstract interface for deallocating a Krylov method. More...

Functions/Subroutines
subroutine	krylov_init (this, max_iter, rel_tol, abs_tol, m, monitor)
	Factory for Krylov solvers. Both creates and initializes the object.
subroutine	krylov_free (this)
	Deallocate a Krylov solver.
subroutine	krylov_set_pc (this, m)
	Setup a Krylov solver's preconditioner.
subroutine	krylov_monitor_start (this, name)
	Monitor start.
subroutine	krylov_monitor_stop (this)
	Monitor stop.
subroutine	krylov_monitor_iter (this, iter, rnorm)
	Monitor iteration.
pure logical function	krylov_is_converged (this, iter, residual)
	Check for convergence.

Variables
integer, parameter, public	ksp_max_iter = 1e3
	Maximum number of iters.
real(kind=rp), parameter, public	ksp_abs_tol = 1d-9
	Absolut tolerance.
real(kind=rp), parameter, public	ksp_rel_tol = 1d-9
	Relative tolerance.

Function/Subroutine Documentation

krylov_free()

subroutine krylov::krylov_free ( class(ksp_t), intent(inout)  this )

private

Todo:

add calls to destroy precon. if necessary

Definition at line 265 of file krylov.f90.

krylov_init()

subroutine krylov::krylov_init ( class(ksp_t), intent(inout), target  this, integer, intent(in)  max_iter, real(kind=rp), intent(in), optional  rel_tol, real(kind=rp), intent(in), optional  abs_tol, class(pc_t), intent(in), optional, target  m, logical, intent(in), optional  monitor  )

private

Parameters

object	The object to be allocated.
n	Size of the vectors the solver operates on.
type_name	The name of the solver type.
max_iter	The maximum number of iterations
abstol	The absolute tolerance, optional.
M	The preconditioner, optional.
monitor	Enable/disable monitoring, optional. Destroy an iterative Krylov type_name Constructor for the base type.
max_iter	Maximum number of iterations.
rel_tol	Relative tolarance for converence.
rel_tol	Absolute tolarance for converence.
M	The preconditioner.

Definition at line 219 of file krylov.f90.

krylov_is_converged()

pure logical function krylov::krylov_is_converged ( class(ksp_t), intent(in)  this, integer, intent(in)  iter, real(kind=rp), intent(in)  residual  )

private

This function checks if the Krylov solver has converged. The solver is considered converged if the residual is less than the absolute tolerance.

Parameters

residual	Residual
iter	Iteration number

Definition at line 343 of file krylov.f90.

krylov_monitor_iter()

subroutine krylov::krylov_monitor_iter ( class(ksp_t), intent(in)  this, integer, intent(in)  iter, real(kind=rp), intent(in)  rnorm  )

private

Definition at line 322 of file krylov.f90.

krylov_monitor_start()

subroutine krylov::krylov_monitor_start ( class(ksp_t), intent(in)  this, character(len=*)  name  )

private

Definition at line 292 of file krylov.f90.

krylov_monitor_stop()

subroutine krylov::krylov_monitor_stop ( class(ksp_t), intent(in)  this )

private

Definition at line 310 of file krylov.f90.

krylov_set_pc()

subroutine krylov::krylov_set_pc ( class(ksp_t), intent(inout)  this, class(pc_t), intent(in), target  m  )

private

Parameters

M	The preconditioner.

Definition at line 274 of file krylov.f90.

Variable Documentation

ksp_abs_tol

real(kind=rp), parameter, public krylov::ksp_abs_tol = 1d-9

Definition at line 52 of file krylov.f90.

ksp_max_iter

integer, parameter, public krylov::ksp_max_iter = 1e3

Definition at line 51 of file krylov.f90.

ksp_rel_tol

real(kind=rp), parameter, public krylov::ksp_rel_tol = 1d-9

Definition at line 53 of file krylov.f90.