Band

LSM band related functions. More...

Functions/Subroutines
subroutine	mod_lsm_band::compute_levelset_band (levelset_field, levelset_band, width)
	Compute the (dist) band around the level set.
subroutine	mod_lsm_band::compute_levelset_band_interface (levelset_field, levelset_band_interface)
	Compute the interface band around the level set (i.e. "cut cells").
pure subroutine	mod_lsm_band::dist_band_to_mask (dist_band, mask, max_dist)
	Compute the mask associated to the dist band, up to a given distance.
pure subroutine	mod_lsm_band::grow_levelset_band (levelset_band, band_value)
	Grow the band by 1.
pure subroutine	mod_lsm_band::grow_levelset_mask (mask)
	Grow the mask by 1.
pure logical function	mod_lsm_band::contains_surface (phi, i, j, k)
	Return true if the cell (i,j,k) contains the surface.
pure logical function	mod_lsm_band::is_face_u_inside_band (band, i, j, k, max_band_distance)
	Return true if the face U(i,j,k) is inside the band.
pure logical function	mod_lsm_band::is_face_v_inside_band (band, i, j, k, max_band_distance)
	Return true if the face V(i,j,k) is inside the band.
pure logical function	mod_lsm_band::is_face_w_inside_band (band, i, j, k, max_band_distance)
	Return true if the face W(i,j,k) is inside the dist band.
pure logical function	mod_lsm_band::is_face_inside_band (band, i, j, k, axis, max_band_distance)
	Return true if the face (i,j,k) along 'axis' is inside he band.

Detailed Description

The LS' band is a region surrounding the interface, on both sides. It can be defined the set of cells that are at a distance to the interface below a certain threshold. In order to obtain more information, we define the dist band as the integer cell distance to the interface, i.e.:

• band(i,j,k) = 0 for cells containing the interface,
• band(i,j,k) = N+1 for cells neighbouring at least one cell of level N,
• band(i,j,k) = levelset_dist_band_outside for cells farther than a certain integer threshold. The idea of the algorithm behind it is pretty simple:

1. Detect all cells containing the interface and assign them the value 0

Function/Subroutine Documentation

compute_levelset_band()

subroutine mod_lsm_band::compute_levelset_band	(	double precision, dimension(:,:,:), intent(in)	levelset_field,
		integer, dimension(:,:,:), intent(inout)	levelset_band,
		integer, intent(in)	width )

Parameters

[in]	levelset_field	The input levelset field
[in,out]	levelset_band	The resulting levelset band
[in]	width	The width (>=0) of the band

Note

The distance band is defined as increasing integer values starting from the close cells (where the value is 'levelset_dist_band_close=0') towards the exterior, up to 'width'.

Todo

Could be optimized by precomputing the corners values

compute_levelset_band_interface()

subroutine mod_lsm_band::compute_levelset_band_interface	(	double precision, dimension(:,:,:), intent(in)	levelset_field,
		integer, dimension(:,:,:), intent(inout)	levelset_band_interface )

Parameters

[in]	levelset_field	The input levelset field
[in,out]	levelset_band_interface	The resulting levelset band

Note

The levelset band is defined as a distance band. Its values are 'levelset_dist_band_close' (i.e. \(0\)) for cells close to the interface and 'levelset_dist_band_outside' anywhere else. The term close stands for cells at a distance \( d < \delta_x \), i.e. when there is a change of sign between to consecutive cells (it's an approximation).

contains_surface()

pure logical function mod_lsm_band::contains_surface	(	double precision, dimension(:,:,:), intent(in)	phi,
		integer, intent(in)	i,
		integer, intent(in)	j,
		integer, intent(in)	k )

Parameters

[in]	phi	the level set field
[in]	i,j,k	where to query

dist_band_to_mask()

pure subroutine mod_lsm_band::dist_band_to_mask	(	integer, dimension(:,:,:), intent(in)	dist_band,
		integer, dimension(:,:,:), intent(inout)	mask,
		integer, intent(in)	max_dist )

Parameters

[in]	dist_band	The input distance band.
[in,out]	mask	The resulting levelset mask
[in]	max_dist	The maximum (absolute, >=0) distance over which the mask is considered

Note

All cells of \( dist_band <= max_dist \) will be put to 1, 0 otherwise.

grow_levelset_band()

pure subroutine mod_lsm_band::grow_levelset_band	(	integer, dimension(:,:,:), intent(inout)	levelset_band,
		integer, intent(in)	band_value )

Parameters

[in,out]	levelset_band	The levelset band to grow
[in]	band_value	What integer value to put in the grown cells

Note

The given band is updated.

The algorithm is: given an existing band, find all unmarked cells neighbouring cells of value 'band_value - 1' and mark them with 'band_value'.

grow_levelset_mask()

pure subroutine mod_lsm_band::grow_levelset_mask

(

integer, dimension(:,:,:), intent(inout)

mask

)

Parameters

[in,out]

mask

The mask to grow

Note

The given mask is updated.

The algorithm is: given an existing mask, mark all cells that are at least neighbouring 1 marked cell.

is_face_inside_band()

pure logical function mod_lsm_band::is_face_inside_band	(	integer, dimension(:,:,:), intent(in)	band,
		integer, intent(in)	i,
		integer, intent(in)	j,
		integer, intent(in)	k,
		integer, intent(in)	axis,
		integer, intent(in)	max_band_distance )

A cell/face is considered inside the dist band if it is below the requested max_band_distance.

Parameters

[in]	band	The input band
[in]	i,j,k	The index of the face
[in]	axis	The axis along which query
[in]	max_band_distance	The maximum requested distance

Precondition

axis \( \in [1:3]\)

is_face_u_inside_band()

pure logical function mod_lsm_band::is_face_u_inside_band	(	integer, dimension(:,:,:), intent(in)	band,
		integer, intent(in)	i,
		integer, intent(in)	j,
		integer, intent(in)	k,
		integer, intent(in)	max_band_distance )

A cell/face is considered inside the dist band if it is below the requested max_band_distance.

Parameters

[in]	band	The input band
[in]	i,j,k	The index of the face
[in]	max_band_distance	The maximum requested distance

is_face_v_inside_band()

pure logical function mod_lsm_band::is_face_v_inside_band	(	integer, dimension(:,:,:), intent(in)	band,
		integer, intent(in)	i,
		integer, intent(in)	j,
		integer, intent(in)	k,
		integer, intent(in)	max_band_distance )

A cell/face is considered inside the dist band if it is below the requested max_band_distance.

Parameters

[in]	band	The input band
[in]	i,j,k	The index of the face
[in]	max_band_distance	The maximum requested distance

is_face_w_inside_band()

pure logical function mod_lsm_band::is_face_w_inside_band	(	integer, dimension(:,:,:), intent(in)	band,
		integer, intent(in)	i,
		integer, intent(in)	j,
		integer, intent(in)	k,
		integer, intent(in)	max_band_distance )

A cell/face is considered inside the dist band if it is below the requested max_band_distance.

Parameters

[in]	band	The input band
[in]	i,j,k	The index of the face
[in]	max_band_distance	The maximum requested distance