adam_rk_object

ADAM, RK class definition.

Source: src/lib/common/adam_rk_object.F90

Dependencies

Contents

• rk_object
• assign_stage
• compute_stage
• compute_stage_ls
• initialize
• initialize_stages
• load_from_file
• update_q
• rk_stored_stages_number
• description

Variables

Name	Type	Attributes	Description
RK_1	character(len=13)	parameter	Parameter of time scheme, Runge-Kutta 1.
RK_2	character(len=13)	parameter	Parameter of time scheme, Runge-Kutta 2.
RK_3	character(len=13)	parameter	Parameter of time scheme, Runge-Kutta 3.
RK_SSP_11	character(len=18)	parameter	Parameter of time scheme, Runge-Kutta SSP 11 (forward Euler).
RK_SSP_22	character(len=18)	parameter	Parameter of time scheme, Runge-Kutta SSP 22.
RK_SSP_33	character(len=18)	parameter	Parameter of time scheme, Runge-Kutta SSP 33.
RK_SSP_54	character(len=18)	parameter	Parameter of time scheme, Runge-Kutta SSP 54.
RK_YOSHIDA	character(len=19)	parameter	Parameter of time scheme, Runge-Kutta Yoshida, symplectic 4.
INI_SECTION_NAME	character(len=11)	parameter	INI (config) file section name containing configs.

Derived Types

rk_object

RK class definition.

Components

Name	Type	Attributes	Description
scheme	character(len=:)	allocatable	RK scheme.
nrk	integer(kind=I4P)		Runge-Kutta stages number.
ark	real(kind=R8P)	allocatable	Runge-Kutta low storage alpha coefficients.
brk	real(kind=R8P)	allocatable	Runge-Kutta low storage beta coefficients.
crk	real(kind=R8P)	allocatable	Runge-Kutta low storage beta coefficients.
alph	real(kind=R8P)	allocatable	Runge-Kutta SSP alpha coefficients.
beta	real(kind=R8P)	allocatable	Runge-Kutta SSP beta coefficients.
gamm	real(kind=R8P)	allocatable	Runge-Kutta SSP gamma coefficients.
ssa	real(kind=R8P)	allocatable	Runge-Kutta sympletic-splitting part A coefficients.
ssb	real(kind=R8P)	allocatable	Runge-Kutta sympletic-splitting part B coefficients.
q_rk	real(kind=R8P)	allocatable	Field cell centered variables, RK stages.
blocks_zeroed	integer(kind=I4P)		Block slots of q_rk zeroed so far (issue #45).
ngc	integer(kind=I4P)	pointer	Number of ghost cells.
ni	integer(kind=I4P)	pointer	Number of cells in i direction.
nj	integer(kind=I4P)	pointer	Number of cells in j direction.
nk	integer(kind=I4P)	pointer	Number of cells in k direction.

Type-Bound Procedures

Name	Attributes	Description
assign_stage	pass(self)	Assign q to RK stage.
compute_stage	pass(self)	Compute RK stage.
compute_stage_ls	pass(self)	Compute RK stage, low storage scheme.
description	pass(self)	Return pretty-printed object description.
initialize	pass(self)	Initialize class.
initialize_stages	pass(self)	Initialize RK stages.
load_from_file	pass(self)	Load config from file.
update_q	pass(self)	Update RK q.

Subroutines

assign_stage

Assign q to RK stage.

subroutine assign_stage(self, field, s, q, phi)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	inout		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
s	integer(kind=I4P)	in		Current stage number.
q	real(kind=R8P)	in		Conservative variables.
phi	real(kind=R8P)	in	optional	IB distance.

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compute_stage

Compute RK stage.

subroutine compute_stage(self, field, s, dt, phi)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	inout		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
s	integer(kind=I4P)	in		Current stage number.
dt	real(kind=R8P)	in		Current time step.
phi	real(kind=R8P)	in	optional	IB distance.

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compute_stage_ls

Compute RK stage, low storage scheme. The first (only) stage is assumed to be the previous time step q solution.

subroutine compute_stage_ls(self, field, s, dt, phi, dq, q)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	in		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
s	integer(kind=I4P)	in		Current RK stage.
dt	real(kind=R8P)	in		Current time step.
phi	real(kind=R8P)	in	optional	IB distance.
dq	real(kind=R8P)	in		Conservative variables residuals.
q	real(kind=R8P)	inout		Conservative variables stage.

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initialize

Initialize class.

subroutine initialize(self, field, grid, file_parameters, scheme)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	inout		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
grid	type(grid_object)	in	target	Grid (sibling realm component, threaded in).
file_parameters	type(file_ini)	in	optional	Simulation parameters ini file handler.
scheme	character(len=*)	in	optional	Runge-Kutta scheme.

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initialize_stages

Initialize RK stages: every stage starts the step as a copy of q in the interior cells.

A block slot is zeroed, ghost cells included, the first time it is active (issue #45). The stage updates write the interior only, and neither the ghost exchange (edge and corner ghosts on null axes) nor the alpha-cadence seam fill (it fills q only) writes every stage ghost cell, while the local ghost fill reads some of them as sources (8-cell restriction). q_rk is not initialized at allocation (zeroing the whole fill-the-node buffer would commit all of it), so those reads saw uninitialized memory (valgrind), zero only when the page happened to be fresh. Zeroing once, not every step, keeps the ghost values a previous step wrote and later steps read before rewriting them; never-written cells read zero, as in the FNL twin (q_rk_gpu is allocated zeroed).

subroutine initialize_stages(self, field, q)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	inout		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
q	real(kind=R8P)	in		Conservative variables.

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load_from_file

Load config from file.

subroutine load_from_file(self, file_parameters, go_on_fail)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	inout		RK object.
file_parameters	type(file_ini)	in		Simulation parameters ini file handler.
go_on_fail	logical	in	optional	Go on if load fails.

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update_q

Update RK q.

subroutine update_q(self, field, dt, phi, q, dq)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	in		RK object.
field	type(field_object)	in		Field (sibling realm component, threaded in).
dt	real(kind=R8P)	in		Current time step.
phi	real(kind=R8P)	in	optional	IB distance.
q	real(kind=R8P)	inout		Conservative variables.
dq	real(kind=R8P)	inout	optional	Conservative variables residuals.

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Functions

rk_stored_stages_number

Return the number of block-sized stage fields rk_object%initialize allocates for a scheme.

Low-storage schemes keep one stage, SSP schemes keep all nrk stages, Yoshida keeps none. It lets an app size its memory budget (realm_object%initialize(fields_number=...)) before the RK object exists; the SSP values must match the nrk set in initialize. An unknown scheme returns -1.

Attributes: pure

Returns: integer(kind=I4P)

function rk_stored_stages_number(scheme) result(stages_number)

Arguments

Name	Type	Intent	Attributes	Description
scheme	character(len=*)	in		Runge-Kutta scheme name.

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description

Return a pretty-formatted object description.

Attributes: pure

Returns: character(len=:)

function description(self) result(desc)

Arguments

Name	Type	Intent	Attributes	Description
self	class(rk_object)	in		RK object.

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