Class mgrid::Stack

ClassList > mgrid > Stack

Grid-level hierarchy for a multigrid solve. More...

• #include <stack.hpp>

Public Attributes

Type	Name
BoundaryConditions	boundaryConditions Finest-level master boundary conditions.
const Level	finestLevel Level index of the finest grid ( numberOfGrids - 1 ).

Public Static Attributes

Type	Name
Level	coarsestLevel = 0 Level index of the coarsest grid (always 0).

Public Functions

Type	Name
	Stack (const Settings & s) Builds the grid hierarchy described by s .
const Axis &	axis (int d) const The x ( d == 0 ) or z (d == 1 ) grid axis, taken from the coarsest level.
std::vector< FDArray >::iterator	begin () Iterator to the coarsest level (enables range- for ).
std::vector< FDArray >::const_iterator	begin () const Const iterator to the coarsest level (enables range- for ).
void	coarsen (Level level) Restricts level level onto levellevel - 1 in place.
void	coarsen (Level level, FDArray & result) Restricts level level intoresult .
std::vector< FDArray >::iterator	end () One-past-the-finest-level iterator (enables range- for ).
std::vector< FDArray >::const_iterator	end () const Const one-past-the-finest-level iterator (enables range- for ).
void	inject (Level level) Injects level level onto levellevel - 1 in place.
void	inject (Level level, FDArray & result) Injects level level intoresult .
FDArray &	operator[] (Level l) Mutable access to the grid at level l .
const FDArray &	operator[] (Level l) const Read-only access to the grid at level l .
void	propagate_boundary_conditions () Down-samples the finest-level boundary conditions onto every coarser level at stride 2.
void	refine (Level level) Interpolates level level onto levellevel + 1 in place.
void	refine (Level level, FDArray & result) Interpolates level level intoresult .
Level	size () const Number of grid levels in the hierarchy.

Detailed Description

Composes a std::vector< FDArray > of grid levels (level 0 is the coarsest, finestLevel the finest). A bounded axis refines n -> 2*(n-1)+1 per level; a periodic axis refines n -> 2*n and requires an even minimumResolution. Unlike the legacy class this does not inherit from std::vector.

Public Attributes Documentation

variable boundaryConditions

Finest-level master boundary conditions.

BoundaryConditions mgrid::Stack::boundaryConditions;

---

variable finestLevel

Level index of the finest grid ( numberOfGrids - 1 ).

const Level mgrid::Stack::finestLevel;

---

Public Static Attributes Documentation

variable coarsestLevel

Level index of the coarsest grid (always 0).

Level mgrid::Stack::coarsestLevel;

---

Public Functions Documentation

function Stack

Builds the grid hierarchy described by s .

explicit mgrid::Stack::Stack (
    const Settings & s
) 

Parameters:

• s solver settings (grid count, coarsest resolution, aspect ratio)

Postcondition:

Every level is sized and zeroed; boundaryConditions holds the default finest-level pattern.

---

function axis

The x ( d == 0 ) or z (d == 1 ) grid axis, taken from the coarsest level.

inline const Axis & mgrid::Stack::axis (
    int d
) const

Parameters:

• d axis selector: 0 for the x axis, anything else for the z axis

Returns:

const reference to that level-0 Axis (point count, spacing, periodicity); every level shares the same periodicity.

---

function begin [1/2]

Iterator to the coarsest level (enables range- for ).

inline std::vector< FDArray >::iterator mgrid::Stack::begin () 

Returns:

begin iterator over the levels

---

function begin [2/2]

Const iterator to the coarsest level (enables range- for ).

inline std::vector< FDArray >::const_iterator mgrid::Stack::begin () const

Returns:

const begin iterator over the levels

---

function coarsen [1/2]

Restricts level level onto levellevel - 1 in place.

void mgrid::Stack::coarsen (
    Level level
) 

Parameters:

• level finer level whose data is restricted; the result is written to level level - 1

Note:

Applies restriction_operator from level level to level level - 1.

---

function coarsen [2/2]

Restricts level level intoresult .

void mgrid::Stack::coarsen (
    Level level,
    FDArray & result
) 

Parameters:

• level finer level whose data is restricted
• result destination grid on the coarser level, overwritten with the restricted field

Note:

Applies restriction_operator from level level into result.

---

function end [1/2]

One-past-the-finest-level iterator (enables range- for ).

inline std::vector< FDArray >::iterator mgrid::Stack::end () 

Returns:

end iterator over the levels

---

function end [2/2]

Const one-past-the-finest-level iterator (enables range- for ).

inline std::vector< FDArray >::const_iterator mgrid::Stack::end () const

Returns:

const end iterator over the levels

---

function inject [1/2]

Injects level level onto levellevel - 1 in place.

void mgrid::Stack::inject (
    Level level
) 

Parameters:

• level finer level whose data is injected to level level - 1

Note:

Applies injection_operator (no averaging); used by the FAS solver for the solution transfer.

---

function inject [2/2]

Injects level level intoresult .

void mgrid::Stack::inject (
    Level level,
    FDArray & result
) 

Parameters:

• level finer level whose data is injected
• result destination grid on the coarser level, overwritten

Note:

Applies injection_operator from level level into result.

---

function operator[]

Mutable access to the grid at level l .

inline FDArray & mgrid::Stack::operator[] (
    Level l
) 

Parameters:

• l level index (coarsestLevel .. finestLevel)

Returns:

reference to that level's FDArray

---

function operator[]

Read-only access to the grid at level l .

inline const FDArray & mgrid::Stack::operator[] (
    Level l
) const

Parameters:

• l level index (coarsestLevel .. finestLevel)

Returns:

const reference to that level's FDArray

---

function propagate_boundary_conditions

Down-samples the finest-level boundary conditions onto every coarser level at stride 2.

void mgrid::Stack::propagate_boundary_conditions () 

Note:

The finest level receives an explicit copy of boundaryConditions; each coarser level L rebuilds every edge as coarse[k] = finer[2*k] (stride 2 from level L + 1), sized to that level's edge extent. An edge whose finest-level condition is periodic is instead filled with a length-matched run of periodicCondition (no value sampling). The copies are computed ONCE: no live aliasing, so mutating Stack::boundaryConditions afterwards does not auto-propagate — a caller must re-invoke propagate_boundary_conditions() (spec §5.5).

---

function refine [1/2]

Interpolates level level onto levellevel + 1 in place.

void mgrid::Stack::refine (
    Level level
) 

Parameters:

• level coarser level whose data is interpolated; the result is written to level level + 1

Note:

Applies interpolation_operator from level level to level level + 1.

---

function refine [2/2]

Interpolates level level intoresult .

void mgrid::Stack::refine (
    Level level,
    FDArray & result
) 

Parameters:

• level coarser level whose data is interpolated
• result destination grid on the finer level, overwritten with the interpolated field

Note:

Applies interpolation_operator from level level into result.

---

function size

Number of grid levels in the hierarchy.

inline Level mgrid::Stack::size () const

Returns:

the level count

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The documentation for this class was generated from the following file include/multigrid/stack.hpp