reference
When
reference is
cell, the direction is crystallographic,
its parent must be a cell and the direction indices must be indicated.
When
reference is
atoms, the direction is atomic and
must contain two non coincident atoms defining a line.
Example: <direction ... reference="cell"/> (default)
Allowed values: cell, atoms (optional)
u, v, w
Set the indices
u, v, w defining a crystallographic direction.
The three indices cannot be all zero. An error is shown when these
indices are not indicated for a crystallographic direction or when
they are indicated for an atomic direction.
Example: <direction ... u="1" v="0" w="0"/> (no default)
Allowed values: integer (required, coupled)
vectors
Set the type of cell vectors,
conventional or
primitive,
used to determine the direction with
u,
v,
w indices.
When the lattice is primitive there is no difference between
conventional or
primitive cell vectors.
An error is shown when
vectors is set for an atomic direction.
Example: <direction ... vectors="conventional"/> (default)
(defined in GAMGI_PHYS_DIRECTION_VECTORS)
Allowed values: conventional, primitive (optional)