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noncopying.py
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noncopying.py
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"""non-copying sends"""
import zmq
import numpy
n = 10
iface = 'inproc://pub'
ctx = zmq.Context()
p = ctx.socket(zmq.PUB)
p.bind(iface)
# connect 2 subs
s1 = ctx.socket(zmq.SUB)
s1.connect(iface)
s1.setsockopt(zmq.SUBSCRIBE, '')
s2 = ctx.socket(zmq.SUB)
s2.connect(iface)
s2.setsockopt(zmq.SUBSCRIBE, '')
A = numpy.random.random((1024,1024))
# send
p.send(A, copy=False)
# recv on 1 non-copy
msg1 = s1.recv(copy=False)
B1 = numpy.frombuffer(msg1.buffer, dtype=A.dtype).reshape(A.shape)
# recv on 2 copy
msg2 = s2.recv(copy=False)
B2 = numpy.frombuffer(buffer(msg2.bytes), dtype=A.dtype).reshape(A.shape)
print((B1==B2).all())
print((B1==A).all())
A[0][0] += 10
print("~")
# after changing A in-place, B1 changes too, proving non-copying sends
print((B1==A).all())
# but B2 is fixed, since it called the msg.bytes attr, which copies
print((B1==B2).all())