def _get_BZ_triplets_at_q(grid_point, bz_grid: BZGrid, map_triplets):
"""Grid point triplets are searched considering BZ surface.
Looking for q+q'+q''=G with smallest |G|. In this condition,
a pair in (q, q', q'') can be translationally equivalent points.
This is treated on BZ-grid.
Note
----
Symmetry information of triplets is encoded in ``map_triplets``.
Parameters
----------
grid_number : int
Grid point of q0 as defined by bz_grid.
bz_grid : BZGrid
Data structure to represent BZ grid.
map_triplets : ndarray or None
Mapping table of all triplets to symmetrically
independent tripelts. More precisely, this gives a list of
index mapping from all q-points to independent q' of
q+q'+q''=G. Considering q' is enough because q is fixed and
q''=G-q-q' where G is automatically determined to choose
smallest |G| without considering BZ surface (see docstring of
_get_BZ_triplets_at_q.)
shape=(prod(mesh),), dtype='int_'
Returns
-------
triplets : ndarray
Symmetry reduced number of triplets are stored as grid point
integer numbers.
shape=(n_triplets, 3), dtype='int_'
ir_weights : ndarray
Weights of triplets at a fixed q0.
shape=(n_triplets,), dtype='int_'
"""
import phono3py._phono3py as phono3c
weights = np.zeros(len(map_triplets), dtype="int_")
for g in map_triplets:
weights[g] += 1
ir_weights = np.extract(weights > 0, weights)
triplets = -np.ones((len(ir_weights), 3), dtype="int_")
num_ir_ret = phono3c.BZ_triplets_at_q(
triplets,
grid_point,
bz_grid.addresses,
bz_grid.gp_map,
map_triplets,
np.array(bz_grid.D_diag, dtype="int_"),
bz_grid.Q,
bz_grid.store_dense_gp_map * 1 + 1,
)
assert num_ir_ret == len(ir_weights)
return triplets, np.array(ir_weights, dtype="int_")
def _get_BZ_triplets_at_q(grid_point, bz_grid_address, bz_map, map_triplets,
mesh):
import phono3py._phono3py as phono3c
weights = np.zeros(len(map_triplets), dtype='intc')
for g in map_triplets:
weights[g] += 1
ir_weights = np.extract(weights > 0, weights)
triplets = np.zeros((len(ir_weights), 3), dtype=bz_map.dtype)
# triplets are overwritten.
num_ir_ret = phono3c.BZ_triplets_at_q(triplets, grid_point,
bz_grid_address, bz_map,
map_triplets,
np.array(mesh, dtype='intc'))
assert num_ir_ret == len(ir_weights)
return triplets, np.array(ir_weights, dtype='intc')
def _get_BZ_triplets_at_q(grid_point, bz_grid_address, bz_map, map_triplets,
mesh):
"""grid_address is overwritten."""
import phono3py._phono3py as phono3c
weights = np.zeros_like(map_triplets)
for g in map_triplets:
weights[g] += 1
ir_weights = np.extract(weights > 0, weights)
triplets = np.zeros((len(ir_weights), 3), dtype='intc')
num_ir_ret = phono3c.BZ_triplets_at_q(triplets, grid_point,
bz_grid_address, bz_map,
map_triplets,
np.array(mesh, dtype='intc'))
return triplets, ir_weights