tree_amg_multigrid Module Reference

Implements multigrid using the TreeAMG hierarchy structure. USE: More...

Data Types
type	tamg_solver_t
	Type for the TreeAMG solver. More...
type	tamg_wrk_t

Functions/Subroutines
subroutine	tamg_mg_init (this, ax, xh, coef, msh, gs_h, nlvls, blst, max_iter, cheby_degree)
	Initialization of the TreeAMG multigrid solver.
subroutine	tamg_mg_free (this)
	free tree amg solver object
subroutine	tamg_mg_invalidate_eigs (this)
	Re-estimate every level's eigenvalues on the next solve. Needed when the operator changes underneath the hierarchy.
subroutine	tamg_mg_set_eig_refresh (this, warm_start, power_its_refresh)
	Set the eigenvalue re-estimation policy on every level.
subroutine	tamg_mg_solve (this, z, r, n)
	Solver function for the TreeAMG solver object.
subroutine	tamg_mg_cycle (this, zero_initial_guess)
	multigrid cycle for the TreeAMG solver object
subroutine	tamg_mg_cycle_d (this, zero_initial_guess)
	multigrid cycle for the TreeAMG solver object on device
subroutine	calc_resid (r, x, b, amg, lvl, n)
	Wrapper function to calculate residyal.
subroutine	print_preagg_info (lvl, nagg, agg_type)
subroutine	print_resid_info (r, x, b, r_d, x_d, b_d, amg, lvl, n)
subroutine	fill_lvl_map (amg)
	Create index mapping between levels and directly to finest level.
subroutine	build_agg_csr (amg)
	Build the transpose of map_finest2lvl in CSR form: for every aggregate on a level, the list of finest-level dofs that map to it. This lets the flat matvec walk aggregates rather than dofs, so its restriction becomes a segmented reduction with disjoint writes instead of an atomic scatter. Two O(n) passes per level.

Detailed Description

type(tamg_hierarchy_t) :: amg type(tamg_solver_t) :: amg_solver

call amginit(ax, Xh, coef, msh, gs_h, 3) call amg_solverinit(amg, niter)

call amg_solversolve(xx, f, n)

Function/Subroutine Documentation

build_agg_csr()

subroutine tree_amg_multigrid::build_agg_csr ( type(tamg_hierarchy_t), intent(inout)  amg )

private

Parameters

amg	The tamg hierarchy, with the level maps already filled

Cache-line padding for the per-thread partials, in elements of rp. 32 doubles = 256 B, the A64FX line; a multiple of the 64 B line everywhere else.

Definition at line 615 of file tree_amg_multigrid.f90.

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calc_resid()

subroutine tree_amg_multigrid::calc_resid ( real(kind=rp), dimension(n), intent(inout)  r, real(kind=rp), dimension(n), intent(inout)  x, real(kind=rp), dimension(n), intent(inout)  b, type(tamg_hierarchy_t), intent(inout)  amg, integer, intent(in)  lvl, integer, intent(in)  n  )

private

Parameters

r	The residual to be returned
x	The current solution
b	The right-hand side
amg	The TreeAMG object
lvl	Current level of the cycle
n	Number of dofs

Definition at line 504 of file tree_amg_multigrid.f90.

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fill_lvl_map()

subroutine tree_amg_multigrid::fill_lvl_map ( type(tamg_hierarchy_t), intent(inout)  amg )

private

Parameters

amg	The tamg hierarchy

Definition at line 558 of file tree_amg_multigrid.f90.

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print_preagg_info()

subroutine tree_amg_multigrid::print_preagg_info ( integer, intent(in)  lvl, integer, intent(in)  nagg, integer, intent(in)  agg_type  )

private

Definition at line 517 of file tree_amg_multigrid.f90.

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print_resid_info()

subroutine tree_amg_multigrid::print_resid_info ( real(kind=rp), dimension(n), intent(inout)  r, real(kind=rp), dimension(n), intent(inout)  x, real(kind=rp), dimension(n), intent(inout)  b, type(c_ptr)  r_d, type(c_ptr)  x_d, type(c_ptr)  b_d, type(tamg_hierarchy_t), intent(inout)  amg, integer, intent(in)  lvl, integer, intent(in)  n  )

private

Definition at line 536 of file tree_amg_multigrid.f90.

tamg_mg_cycle()

subroutine tree_amg_multigrid::tamg_mg_cycle ( class(tamg_solver_t), intent(inout), target  this, logical, intent(inout)  zero_initial_guess  )

private

Parameters

this	The Solver object.
zero_initial_guess	Flag for when the initial guess is zero

Definition at line 354 of file tree_amg_multigrid.f90.

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tamg_mg_cycle_d()

subroutine tree_amg_multigrid::tamg_mg_cycle_d ( class(tamg_solver_t), intent(inout), target  this, logical, intent(inout)  zero_initial_guess  )

private

Parameters

this	The Solver object.
zero_initial_guess	Flag for when the initial guess is zero

Definition at line 423 of file tree_amg_multigrid.f90.

tamg_mg_free()

subroutine tree_amg_multigrid::tamg_mg_free ( class(tamg_solver_t), intent(inout), target  this )

private

Definition at line 230 of file tree_amg_multigrid.f90.

tamg_mg_init()

subroutine tree_amg_multigrid::tamg_mg_init	(	class(tamg_solver_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,
		integer, intent(in)	max_iter,
		integer, intent(in)	cheby_degree
	)

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
max_iter	Number of AMG iterations

Definition at line 111 of file tree_amg_multigrid.f90.

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tamg_mg_invalidate_eigs()

subroutine tree_amg_multigrid::tamg_mg_invalidate_eigs ( class(tamg_solver_t), intent(inout)  this )

private

Definition at line 273 of file tree_amg_multigrid.f90.

tamg_mg_set_eig_refresh()

subroutine tree_amg_multigrid::tamg_mg_set_eig_refresh ( class(tamg_solver_t), intent(inout)  this, logical, intent(in)  warm_start, integer, intent(in)  power_its_refresh  )

private

Parameters

warm_start	Restart from the saved eigenvector
power_its_refresh	Iterations to use when restarting

Definition at line 285 of file tree_amg_multigrid.f90.

tamg_mg_solve()

subroutine tree_amg_multigrid::tamg_mg_solve ( class(tamg_solver_t), intent(inout)  this, real(kind=rp), dimension(n), intent(inout)  z, real(kind=rp), dimension(n), intent(inout)  r, integer, intent(in)  n  )

private

Parameters

z	The solution to be returned
r	The right-hand side
n	Number of dofs

Definition at line 301 of file tree_amg_multigrid.f90.

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