CPU implementation of the right-preconditioned BiCGStab method. More...

Inheritance diagram for bicgstab::bicgstab_t:

Collaboration diagram for bicgstab::bicgstab_t:

Public Member Functions
procedure, pass(this)	init (this, n, max_iter, m, rel_tol, abs_tol, monitor)
	Initialise a CPU BiCGStab solver.

procedure, pass(this)	free (this)
	Free a CPU BiCGStab solver.

procedure, pass(this)	solve (this, ax, x, f, n, coef, bc_projector, gs_h, niter)
	Solve a linear system with the CPU BiCGStab method.

procedure, pass(this)	solve_coupled (this, ax, x, y, z, fx, fy, fz, n, coef, bc_projector, gs_h, niter)
	Solve three independent systems with the CPU BiCGStab method.

procedure(ksp_init_intrf), deferred, pass(this)	init (this, n, max_iter, m, rel_tol, abs_tol, monitor)
	Constructor.

procedure, pass(this)	ksp_init (this, max_iter, rel_tol, abs_tol, m, monitor)
	Base type constructor.

procedure, pass(this)	ksp_free (this)
	Base type destructor.

procedure, pass(this)	set_pc (this, m)
	Set preconditioner.

procedure(ksp_method), deferred, pass	solve (this, ax, x, f, n, coef, bc_projector, gs_h, niter)
	Solve the system.

procedure(ksp_method_coupled), deferred, pass	solve_coupled (this, ax, x, y, z, fx, fy, fz, n, coef, bc_projector, gs_h, niter)
	Solve the system (coupled version).

procedure, pass(this)	monitor_start (this, name)
	Monitor start.

procedure, pass(this)	monitor_stop (this)
	Monitor stop.

procedure, pass(this)	monitor_iter (this, iter, rnorm)
	Monitor iteration.

procedure, pass(this)	is_converged (this, iter, residual)
	Check for convergence.

procedure(ksp_t_free), deferred, pass	free (this)
	Destructor.

Public Attributes
real(kind=rp), dimension(:), allocatable	p
	Search direction \(p\).

real(kind=rp), dimension(:), allocatable	p_hat
	Preconditioned search direction \(\hat{p} = M^{-1}p\).

real(kind=rp), dimension(:), allocatable	r
	Residual \(r\).

real(kind=rp), dimension(:), allocatable	s
	Intermediate residual \(s = r - \alpha v\).

real(kind=rp), dimension(:), allocatable	s_hat
	Preconditioned intermediate residual \(\hat{s} = M^{-1}s\).

real(kind=rp), dimension(:), allocatable	t
	Operator action \(t = A\hat{s}\).

real(kind=rp), dimension(:), allocatable	v
	Operator action \(v = A\hat{p}\).

class(pc_t), pointer	m => null()
	Preconditioner.

real(kind=rp)	rel_tol
	Relative tolerance.

real(kind=rp)	abs_tol
	Absolute tolerance.

integer	max_iter
	Maximum number of iterations.

class(pc_t), allocatable	m_ident
	Internal preconditioner (Identity)

logical	monitor
	Turn on/off monitoring.

Detailed Description

The solver starts from a zero initial guess and uses the preconditioner provided by ksp_t. The coupled interface solves the three components independently and does not apply a coupled operator.

Definition at line 58 of file bicgstab.f90.

Member Function/Subroutine Documentation

◆ free() [1/2]

procedure, pass(this) bicgstab::bicgstab_t::free ( class(bicgstab_t), intent(inout) this )

Definition at line 77 of file bicgstab.f90.

◆ free() [2/2]

procedure(ksp_t_free), deferred, pass krylov::ksp_t::free ( class(ksp_t), intent(inout) this )

pure virtualinherited

Definition at line 103 of file krylov.f90.

◆ init() [1/2]

procedure, pass(this) bicgstab::bicgstab_t::init	(	class(bicgstab_t), intent(inout), target	this,
		integer, intent(in)	n,
		integer, intent(in)	max_iter,
		class(pc_t), intent(in), optional, target	m,
		real(kind=rp), intent(in), optional	rel_tol,
		real(kind=rp), intent(in), optional	abs_tol,
		logical, intent(in), optional	monitor
	)

Parameters

n	Number of degrees of freedom.
max_iter	Maximum number of iterations.
M	Optional preconditioner. An identity preconditioner is used if absent.
rel_tol	Optional relative convergence tolerance.
abs_tol	Optional absolute convergence tolerance.
monitor	Optional switch for logging the residual at each iteration.

Definition at line 75 of file bicgstab.f90.

◆ init() [2/2]

procedure(ksp_init_intrf), deferred, pass(this) krylov::ksp_t::init	(	class(ksp_t), intent(inout), target	this,
		integer, intent(in)	n,
		integer, intent(in)	max_iter,
		class(pc_t), intent(in), optional, target	m,
		real(kind=rp), intent(in), optional	rel_tol,
		real(kind=rp), intent(in), optional	abs_tol,
		logical, intent(in), optional	monitor
	)

pure virtualinherited

Definition at line 83 of file krylov.f90.

◆ is_converged()

procedure, pass(this) krylov::ksp_t::is_converged	(	class(ksp_t), intent(in)	this,
		integer, intent(in)	iter,
		real(kind=rp), intent(in)	residual
	)

inherited

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 101 of file krylov.f90.

◆ ksp_free()

procedure, pass(this) krylov::ksp_t::ksp_free ( class(ksp_t), intent(inout) this )

inherited

Definition at line 87 of file krylov.f90.

◆ ksp_init()

procedure, pass(this) krylov::ksp_t::ksp_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
	)

inherited

Parameters

max_iter	Maximum number of iterations.
rel_tol	Relative tolarance for converence.
rel_tol	Absolute tolarance for converence.
M	The preconditioner.

Definition at line 85 of file krylov.f90.

◆ monitor_iter()

procedure, pass(this) krylov::ksp_t::monitor_iter	(	class(ksp_t), intent(in)	this,
		integer, intent(in)	iter,
		real(kind=rp), intent(in)	rnorm
	)

inherited

Definition at line 99 of file krylov.f90.

◆ monitor_start()

procedure, pass(this) krylov::ksp_t::monitor_start	(	class(ksp_t), intent(in)	this,
		character(len=*)	name
	)

inherited

Definition at line 95 of file krylov.f90.

◆ monitor_stop()

procedure, pass(this) krylov::ksp_t::monitor_stop ( class(ksp_t), intent(in) this )

inherited

Definition at line 97 of file krylov.f90.

◆ set_pc()

procedure, pass(this) krylov::ksp_t::set_pc	(	class(ksp_t), intent(inout)	this,
		class(pc_t), intent(in), target	m
	)

inherited

Parameters

M	The preconditioner.

Definition at line 89 of file krylov.f90.

◆ solve() [1/2]

procedure, pass(this) bicgstab::bicgstab_t::solve	(	class(bicgstab_t), intent(inout)	this,
		class(ax_t), intent(in)	ax,
		type(field_t), intent(inout)	x,
		real(kind=rp), dimension(n), intent(in)	f,
		integer, intent(in)	n,
		type(coef_t), intent(inout)	coef,
		class(scalar_bc_projector_t), intent(inout)	bc_projector,
		type(gs_t), intent(inout)	gs_h,
		integer, intent(in), optional	niter
	)

The initial guess in x is discarded and the iteration starts from zero.

Parameters

Ax	Linear operator.
x	Solution field.
f	Right-hand side.
n	Number of degrees of freedom.
coef	Spectral element coefficients and multiplicity weights.
bc_projector	Projector for dirichlet boundary nodes.
gs_h	Gather-scatter handle used to assemble the operator result.
niter	Optional maximum number of iterations, overriding the configured value.

Returns: Convergence information for the solve.

Definition at line 79 of file bicgstab.f90.

◆ solve() [2/2]

procedure(ksp_method), deferred, pass krylov::ksp_t::solve	(	class(ksp_t), intent(inout)	this,
		class(ax_t), intent(in)	ax,
		type(field_t), intent(inout)	x,
		real(kind=rp), dimension(n), intent(in)	f,
		integer, intent(in)	n,
		type(coef_t), intent(inout)	coef,
		class(scalar_bc_projector_t), intent(inout)	bc_projector,
		type(gs_t), intent(inout)	gs_h,
		integer, intent(in), optional	niter
	)

pure virtualinherited

Definition at line 91 of file krylov.f90.

◆ solve_coupled() [1/2]

procedure, pass(this) bicgstab::bicgstab_t::solve_coupled	(	class(bicgstab_t), intent(inout)	this,
		class(ax_t), intent(in)	ax,
		type(field_t), intent(inout)	x,
		type(field_t), intent(inout)	y,
		type(field_t), intent(inout)	z,
		real(kind=rp), dimension(n), intent(in)	fx,
		real(kind=rp), dimension(n), intent(in)	fy,
		real(kind=rp), dimension(n), intent(in)	fz,
		integer, intent(in)	n,
		type(coef_t), intent(inout)	coef,
		class(vector_bc_projector_t), intent(inout)	bc_projector,
		type(gs_t), intent(inout)	gs_h,
		integer, intent(in), optional	niter
	)

This routine sequentially invokes the scalar solver for each component.

Parameters

Ax	Linear operator.
x	Solution field for the first component.
y	Solution field for the second component.
z	Solution field for the third component.
fx	Right-hand side for the first component.
fy	Right-hand side for the second component.
fz	Right-hand side for the third component.
n	Number of degrees of freedom per component.
coef	Spectral element coefficients and multiplicity weights.
blstx	Boundary conditions for the first component.
blsty	Boundary conditions for the second component.
blstz	Boundary conditions for the third component.
gs_h	Gather-scatter handle used to assemble operator results.
niter	Optional maximum number of iterations, overriding the configured value.

Returns: Convergence information for each component.

Definition at line 81 of file bicgstab.f90.

◆ solve_coupled() [2/2]

procedure(ksp_method_coupled), deferred, pass krylov::ksp_t::solve_coupled	(	class(ksp_t), intent(inout)	this,
		class(ax_t), intent(in)	ax,
		type(field_t), intent(inout)	x,
		type(field_t), intent(inout)	y,
		type(field_t), intent(inout)	z,
		real(kind=rp), dimension(n), intent(in)	fx,
		real(kind=rp), dimension(n), intent(in)	fy,
		real(kind=rp), dimension(n), intent(in)	fz,
		integer, intent(in)	n,
		type(coef_t), intent(inout)	coef,
		class(vector_bc_projector_t), intent(inout)	bc_projector,
		type(gs_t), intent(inout)	gs_h,
		integer, intent(in), optional	niter
	)

pure virtualinherited

Definition at line 93 of file krylov.f90.

Member Data Documentation

◆ abs_tol

real(kind=rp) krylov::ksp_t::abs_tol

inherited

Definition at line 77 of file krylov.f90.

◆ m

class(pc_t), pointer krylov::ksp_t::m => null()

inherited

Definition at line 75 of file krylov.f90.

◆ m_ident

class(pc_t), allocatable krylov::ksp_t::m_ident

inherited

Definition at line 79 of file krylov.f90.

◆ max_iter

integer krylov::ksp_t::max_iter

inherited

Definition at line 78 of file krylov.f90.

◆ monitor

logical krylov::ksp_t::monitor

inherited

Definition at line 80 of file krylov.f90.

◆ p

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::p

Definition at line 60 of file bicgstab.f90.

◆ p_hat

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::p_hat

Definition at line 62 of file bicgstab.f90.

◆ r

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::r

Definition at line 64 of file bicgstab.f90.

◆ rel_tol

real(kind=rp) krylov::ksp_t::rel_tol

inherited

Definition at line 76 of file krylov.f90.

◆ s

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::s

Definition at line 66 of file bicgstab.f90.

◆ s_hat

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::s_hat

Definition at line 68 of file bicgstab.f90.

◆ t

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::t

Definition at line 70 of file bicgstab.f90.

◆ v

real(kind=rp), dimension(:), allocatable bicgstab::bicgstab_t::v

Definition at line 72 of file bicgstab.f90.

The documentation for this type was generated from the following file:

/home/runner/work/neko/neko/src/krylov/bcknd/cpu/bicgstab.f90

Public Member Functions

Public Attributes

Detailed Description

Member Function/Subroutine Documentation

◆ free() [1/2]

◆ free() [2/2]

◆ init() [1/2]

◆ init() [2/2]

◆ is_converged()

◆ ksp_free()

◆ ksp_init()

◆ monitor_iter()

◆ monitor_start()

◆ monitor_stop()

◆ set_pc()

◆ solve() [1/2]

◆ solve() [2/2]

◆ solve_coupled() [1/2]

◆ solve_coupled() [2/2]

Member Data Documentation

◆ abs_tol

◆ m

◆ m_ident

◆ max_iter

◆ monitor

◆ p

◆ p_hat

◆ r

◆ rel_tol

◆ s

◆ s_hat

◆ t

◆ v