def test_trimesh_dask_partitions(npartitions):
"""Assert that when two triangles share an edge that would normally get
double-drawn, the edge is only drawn for the rightmost (or bottommost)
triangle.
"""
# Test left/right edge shared
verts = dd.from_pandas(pd.DataFrame({
'x': [4, 1, 5, 5, 5, 4],
'y': [4, 5, 5, 5, 4, 4]
}),
npartitions=npartitions)
tris = dd.from_pandas(pd.DataFrame({
'v0': [0, 3],
'v1': [1, 4],
'v2': [2, 5],
'val': [1, 2]
}),
npartitions=npartitions)
cvs = ds.Canvas(plot_width=20,
plot_height=20,
x_range=(0, 5),
y_range=(0, 5))
# Precompute mesh with dask dataframes
mesh = du.mesh(verts, tris)
# Make sure mesh is a dask DataFrame
assert isinstance(mesh, dd.DataFrame)
# Check mesh length
n = len(mesh)
assert n == 6
# Make sure we have expected number of partitions
expected_chunksize = int(np.ceil(len(mesh) / (3 * npartitions)) * 3)
expected_npartitions = int(np.ceil(n / expected_chunksize))
assert expected_npartitions == mesh.npartitions
# Make sure triangles don't straddle partitions
partitions_lens = mesh.map_partitions(len).compute()
for partitions_len in partitions_lens:
assert partitions_len % 3 == 0
agg = cvs.trimesh(verts, tris, mesh)
sol = np.array([
[0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
],
dtype='i4')
np.testing.assert_array_equal(
np.flipud(agg.fillna(0).astype('i4').values)[:5], sol)
def _precompute(self, element, agg):
from datashader.utils import mesh
if element.vdims and getattr(agg, 'column', None) not in element.nodes.vdims:
simplices = element.dframe([0, 1, 2, 3])
verts = element.nodes.dframe([0, 1])
elif element.nodes.vdims:
simplices = element.dframe([0, 1, 2])
verts = element.nodes.dframe([0, 1, 3])
for c, dtype in zip(simplices.columns[:3], simplices.dtypes):
if dtype.kind != 'i':
simplices[c] = simplices[c].astype('int')
return {'mesh': mesh(verts, simplices), 'simplices': simplices,
'vertices': verts}
def _precompute(self, element):
from datashader.utils import mesh
if element.vdims:
simplices = element.dframe([0, 1, 2, 3])
verts = element.nodes.dframe([0, 1])
elif element.nodes.vdims:
simplices = element.dframe([0, 1, 2])
verts = element.nodes.dframe([0, 1, 3])
return {
'mesh': mesh(verts, simplices),
'simplices': simplices,
'vertices': verts
}
