Implements the base type for TreeAMG hierarchy structure.

Data Types
type	tamg_hierarchy_t
	Type for a TreeAMG hierarchy. More...

type	tamg_lvl_t
	Type for storing TreeAMG level information. More...

type	tamg_node_t
	Type for storing TreeAMG tree node information. More...

Functions/Subroutines
subroutine	tamg_init (this, ax, xh, coef, msh, gs_h, nlvls, blst)
	Initialization of TreeAMG hierarchy.

subroutine	tamg_free (this)
	deallocate tamg hierarchy

subroutine, public	tamg_lvl_init (tamg_lvl, lvl, nnodes, ndofs)
	Initialization of a TreeAMG level.

subroutine	lvl_free (this)
	deallocate tamg level

subroutine, public	tamg_node_init (node, gid, ndofs)
	Initialization of a TreeAMG tree node.

subroutine	node_free (this)
	deallocate tamg tree node

recursive subroutine	tamg_matvec (this, vec_out, vec_in, lvl_out)
	Wrapper for matrix vector product using the TreeAMG hierarchy structure b=Ax done as vec_out = A * vec_in.

recursive subroutine	tamg_matvec_impl (this, vec_out, vec_in, lvl, lvl_out)
	Matrix vector product using the TreeAMG hierarchy structure b=Ax done as vec_out = A * vec_in This is done on a level by level basis.

recursive subroutine	tamg_matvec_flat_impl (this, vec_out, vec_in, lvl_blah, lvl_out)
	Ignore this. For piecewise constant, can create index map directly to finest level.

subroutine	tamg_restriction_operator (this, vec_out, vec_in, lvl)
	Restriction operator for TreeAMG. vec_out = R * vec_in.

subroutine	tamg_prolongation_operator (this, vec_out, vec_in, lvl)
	Prolongation operator for TreeAMG. vec_out = P * vec_in.

subroutine	tamg_device_matvec_flat_impl (this, vec_out, vec_in, vec_out_d, vec_in_d, lvl_out)

subroutine	tamg_device_restriction_operator (this, vec_out_d, vec_in_d, lvl)

subroutine	tamg_device_prolongation_operator (this, vec_out_d, vec_in_d, lvl, vec_out)

Function/Subroutine Documentation

◆ lvl_free()

subroutine tree_amg::lvl_free ( class(tamg_lvl_t), intent(inout) this )

private

Definition at line 227 of file tree_amg.f90.

◆ node_free()

subroutine tree_amg::node_free ( class(tamg_node_t), intent(inout) this )

private

Definition at line 295 of file tree_amg.f90.

◆ tamg_device_matvec_flat_impl()

subroutine tree_amg::tamg_device_matvec_flat_impl	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		type(c_ptr)	vec_out_d,
		type(c_ptr)	vec_in_d,
		integer, intent(in)	lvl_out
	)

private

isleaf true

pass down through hierarchy

Map input level to finest level

Average on overlapping dofs

Finest level matvec (Call local finite element assembly)

Map finest level matvec back to output level

Definition at line 578 of file tree_amg.f90.

◆ tamg_device_prolongation_operator()

subroutine tree_amg::tamg_device_prolongation_operator	(	class(tamg_hierarchy_t), intent(inout)	this,
		type(c_ptr)	vec_out_d,
		type(c_ptr)	vec_in_d,
		integer, intent(in)	lvl,
		real(kind=rp), dimension(:), intent(inout)	vec_out
	)

private

Definition at line 636 of file tree_amg.f90.

◆ tamg_device_restriction_operator()

subroutine tree_amg::tamg_device_restriction_operator	(	class(tamg_hierarchy_t), intent(inout)	this,
		type(c_ptr)	vec_out_d,
		type(c_ptr)	vec_in_d,
		integer, intent(in)	lvl
	)

private

Definition at line 621 of file tree_amg.f90.

◆ tamg_free()

subroutine tree_amg::tamg_free ( class(tamg_hierarchy_t), intent(inout) this )

private

Definition at line 173 of file tree_amg.f90.

◆ tamg_init()

subroutine tree_amg::tamg_init	(	class(tamg_hierarchy_t), intent(inout), target	this,
		class(ax_t), intent(in), target	ax,
		type(space_t), intent(in), target	xh,
		type(coef_t), intent(in), target	coef,
		type(mesh_t), intent(in), target	msh,
		type(gs_t), intent(in), target	gs_h,
		integer, intent(in)	nlvls,
		type(bc_list_t), intent(in), target	blst
	)

Parameters

ax	Finest level matvec operator
Xh	Finest level field
coef	Finest level coeff thing
msh	Finest level mesh information
gs_h	Finest level gather scatter operator
nlvls	Number of levels for the TreeAMG hierarchy
blst	Finest level BC list

Definition at line 138 of file tree_amg.f90.

◆ tamg_lvl_init()

subroutine, public tree_amg::tamg_lvl_init	(	type(tamg_lvl_t), intent(inout)	tamg_lvl,
		integer, intent(in)	lvl,
		integer, intent(in)	nnodes,
		integer, intent(in)	ndofs
	)

Parameters

tamg_lvl	The TreeAMG level
lvl	The level id
nnodes	Number of nodes on the level (number of aggregates)
ndofs	Number of dofs on the level

Definition at line 198 of file tree_amg.f90.

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◆ tamg_matvec()

recursive subroutine tree_amg::tamg_matvec	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		integer, intent(in)	lvl_out
	)

private

Parameters

vec_out	Result of Ax
vec_in	Vector to be multiplied by linear system. A * vec_in
lvl_out	Level of the TreeAMG hierarchy on which the matvec is done. This also specifies the hieararchy level of the incoming vector

Definition at line 315 of file tree_amg.f90.

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◆ tamg_matvec_flat_impl()

recursive subroutine tree_amg::tamg_matvec_flat_impl	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		integer, intent(in)	lvl_blah,
		integer, intent(in)	lvl_out
	)

private

isleaf true

pass down through hierarchy

Map input level to finest level. Walking the aggregates rather than the dofs reads vec_in once per aggregate and broadcasts it, instead of doing an indirect load per dof.

Average on overlapping dofs

Finest level matvec (Call local finite element assembly)

Map finest level matvec back to output level. This is a segmented reduction, so drive it from the aggregate side: each aggregate is owned by exactly one thread, which makes the writes to vec_out disjoint. No atomics (there is no hardware fp64 atomic add on AArch64, so !$omp atomic there becomes a CAS retry loop, and the aggregation map guarantees maximal contention on it), no pre-zeroing, and a deterministic summation order.

Too few aggregates to hand every thread one; the coarsest level has exactly one, from aggregate_end. Reduce over the dofs into per-thread partials and merge, as in the GMRES Gram-Schmidt hp(:,tid). agg_part's leading dimension is padded to a cache line by build_agg_csr, so the columns do not false share; it is tiny here, so zero all of it up front: capping the team at nthrds still permits a smaller team, whose unused columns the merge below would otherwise read uninitialised.

Definition at line 393 of file tree_amg.f90.

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◆ tamg_matvec_impl()

recursive subroutine tree_amg::tamg_matvec_impl	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		integer, intent(in)	lvl,
		integer, intent(in)	lvl_out
	)

private

Parameters

vec_out	The vector to be returned by level lvl
vec_in	The vector pased to level lvl
lvl	The current level of the matvec (wrt tree traversal)
lvl_out	Level of the TreeAMG hierarchy on which the matvec is output.

isleaf true If on finest level, pass to neko ax_t matvec operator

Call local finite element assembly

pass down through hierarchy

lvl is finer than desired output project input vector to finer grid

restrict to coarser grid

lvl is coarser then desired output. Continue down tree

Definition at line 332 of file tree_amg.f90.

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◆ tamg_node_init()

subroutine, public tree_amg::tamg_node_init	(	type(tamg_node_t), intent(inout)	node,
		integer, intent(in)	gid,
		integer, intent(in)	ndofs
	)

Parameters

node	The TreeAMG tree node
gid	The gid for the node
ndofs	Number of dofs in the node

Definition at line 279 of file tree_amg.f90.

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◆ tamg_prolongation_operator()

subroutine tree_amg::tamg_prolongation_operator	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		integer, intent(in)	lvl
	)

private

Parameters

vec_out	The vector to be returned. On level lvl
vec_in	The vector pased into operator. On level lvl-1
lvl	The target level of the returned vector after prolongation (wrt tree traversal)

Definition at line 545 of file tree_amg.f90.

◆ tamg_restriction_operator()

subroutine tree_amg::tamg_restriction_operator	(	class(tamg_hierarchy_t), intent(inout)	this,
		real(kind=rp), dimension(:), intent(inout)	vec_out,
		real(kind=rp), dimension(:), intent(inout)	vec_in,
		integer, intent(in)	lvl
	)

private

Parameters

vec_out	The vector to be returned. On level lvl
vec_in	The vector pased into operator. On level lvl-1
lvl	The target level of the returned vector after restrction (wrt tree traversal)

Definition at line 511 of file tree_amg.f90.

Data Types

Functions/Subroutines

Function/Subroutine Documentation

◆ lvl_free()

◆ node_free()

◆ tamg_device_matvec_flat_impl()

◆ tamg_device_prolongation_operator()

◆ tamg_device_restriction_operator()

◆ tamg_free()

◆ tamg_init()

◆ tamg_lvl_init()

◆ tamg_matvec()

◆ tamg_matvec_flat_impl()

◆ tamg_matvec_impl()

◆ tamg_node_init()

◆ tamg_prolongation_operator()

◆ tamg_restriction_operator()