def broadcast_collect(expr,
broadcastable=Broadcastable,
want_to_broadcast=WantToBroadcast,
no_recurse=None):
""" Collapse expression down using Broadcast - Tabular cases only
Expressions of type Broadcastables are swallowed into Broadcast
operations
>>> t = symbol('t', 'var * {x: int, y: int, z: int, when: datetime}')
>>> expr = (t.x + 2*t.y).distinct()
>>> broadcast_collect(expr)
distinct(Broadcast(_children=(t,), _scalars=(t,), _scalar_expr=t.x + (2 * t.y)))
>>> from blaze import exp
>>> expr = t.x + 2 * exp(-(t.x - 1.3) ** 2)
>>> broadcast_collect(expr)
Broadcast(_children=(t,), _scalars=(t,), _scalar_expr=t.x + (2 * (exp(-((t.x - 1.3) ** 2)))))
"""
if (isinstance(expr, want_to_broadcast) and
iscollection(expr.dshape)):
leaves = leaves_of_type(broadcastable, expr)
expr = broadcast(expr, sorted(leaves, key=str))
if no_recurse is not None and isinstance(expr, no_recurse):
return expr
# Recurse down
children = (
broadcast_collect(i, broadcastable, want_to_broadcast, no_recurse)
for i in expr._inputs
)
return expr._subs({e: c for e, c in zip(expr._inputs, children)})
def post_compute(expr, query, scope=None):
result = query.context.sql(sql_string(query.query))
if iscollection(expr.dshape) and isscalar(expr.dshape.measure):
result = result.map(lambda x: x[0])
return result.collect()
def post_compute(expr, query, scope=None):
result = query.context.sql(sql_string(query.query))
if iscollection(expr.dshape) and isscalar(expr.dshape.measure):
result = result.map(lambda x: x[0])
return result.collect()
