Mesh

Name MeshIndexType
Section Mesh
Type integer
Default idx_cubic

Determine index type. Must be the same for restarting a calculation.

Options:

• idx_cubic:
  Cubic indices are used to map the spatial information to the grid points.
  
• idx_hilbert:
  A Hilbert space-filling curve is used to map the spatial information to the grid points.
  

Name MultigridLevels
Section Mesh
Type integer
Default 4

Number of levels in the grid hierarchy used for multigrid. Positive numbers indicate an absolute number of levels, negative numbers are subtracted from the maximum number of levels possible.

Options:

• max_levels:
  Calculate the optimal number of levels for the grid.
  

Name PeriodicBoundaryMask
Section Mesh
Type block

(Experimental) Defines a mask for which periodic boundaries are replaced by zero boundary conditions.

Name RegriddingInterpolationLevel
Section Mesh
Type integer
Default regridding_linear

Choose the interpolation level for the regridding.

Options:

• regridding_linear:
  Use a trilinear interpolation. This is implemented similar to restriction and prolongation operations in multigrid methods. This ensures that both directions are adjoint to each other.
  
• regridding_nearest_neighbor:
  Use the nearest neighbor for the regridding. This is faster than the linear interpolation.
  

Name RegriddingRescale
Section Mesh
Type integer
Default scale_norm2

Rescale the regridded quantities. Not using a rescaling can lead to bad results if the ratio of the grid spacings is large. The default is to rescale by the 2-norm of the quantity except for generic interpolations (i.e. between curvilinear or non-commensurate grids).

Options:

• scale_none:
  Do not rescale the regridded quantities.
  
• scale_norm2:
  Scale the regridded quantities by the 2-norm of the quantity on the overlapping region of the grid.
  

Name Spacing
Section Mesh
Type float

The spacing between the points in the mesh. This controls the quality of the discretization: smaller spacing gives more precise results but increased computational cost.

When using curvilinear coordinates, this is a canonical spacing that will be changed locally by the transformation. In periodic directions, your spacing may be slightly different than what you request here, since the box size must be an integer multiple of the spacing.

The default value is defined by the image resolution if BoxShape = box_image. Othewise here is no default otherwise.

It is possible to have a different spacing in each one of the Cartesian directions if we define Spacing as block of the form

%Spacing
  spacing_x | spacing_y | spacing_z
%

Name SpiralBoundaryCondition
Section Mesh
Type logical
Default no

(Experimental) If set to yes, Octopus will apply spin-spiral boundary conditions. The momentum of the spin spiral is defined by the variable TDMomentumTransfer