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from mpi4py import MPI
# -----------------------------------------------------------------------------
import struct as _struct
try:
from numpy import empty as _empty
def _array_new(size, typecode, init=0):
a = _empty(size, typecode)
a.fill(init)
return a
def _array_set(ary, value):
ary.fill(value)
def _array_sum(ary):
return ary.sum()
except ImportError:
from array import array as _array
def _array_new(size, typecode, init=0):
return _array(typecode, [init]) * size
def _array_set(ary, value):
for i, _ in enumerate(ary):
ary[i] = value
def _array_sum(ary):
return sum(ary, 0)
# -----------------------------------------------------------------------------
class Counter:
def __init__(self, comm, init=0):
#
size = comm.Get_size()
rank = comm.Get_rank()
mask = 1
while mask < size:
mask <<= 1
mask >>= 1
idx = 0
get_idx = []
acc_idx = []
while mask >= 1:
left = idx + 1
right = idx + (mask<<1)
if rank < mask:
acc_idx.append( left )
get_idx.append( right )
idx = left
else:
acc_idx.append( right )
get_idx.append( left )
idx = right
rank = rank % mask
mask >>= 1
#
typecode = 'i'
datatype = MPI.INT
itemsize = datatype.Get_size()
#
root = 0
rank = comm.Get_rank()
if rank == root:
nlevels = len(get_idx) + 1
nentries = (1<<nlevels) - 1
self.mem = MPI.Alloc_mem(nentries*itemsize, MPI.INFO_NULL)
self.mem[:] = _struct.pack(typecode, init) * nentries
else:
self.mem = None
#
self.win = MPI.Win.Create(self.mem, itemsize, MPI.INFO_NULL, comm)
self.acc_type = datatype.Create_indexed_block(1, acc_idx).Commit()
self.get_type = datatype.Create_indexed_block(1, get_idx).Commit()
self.acc_buf = _array_new(len(acc_idx), typecode)
self.get_buf = _array_new(len(get_idx), typecode)
self.myval = 0
def free(self):
if self.win:
self.win.Free()
if self.mem:
MPI.Free_mem(self.mem)
self.mem = None
if self.get_type:
self.get_type.Free()
if self.acc_type:
self.acc_type.Free()
def next(self, increment=1):
_array_set(self.acc_buf, increment)
root = 0
self.win.Lock(root)
self.win.Get(self.get_buf, root, [0, 1, self.get_type])
self.win.Accumulate(self.acc_buf, root, [0, 1, self.acc_type], MPI.SUM)
self.win.Unlock(root)
nxtval = self.myval + _array_sum(self.get_buf)
self.myval += increment
return nxtval
# -----------------------------------------------------------------------------
class Mutex:
def __init__(self, comm):
self.counter = Counter(comm)
def __enter__(self):
self.lock()
return self
def __exit__(self, *exc):
self.unlock()
return None
def free(self):
self.counter.free()
def lock(self):
value = self.counter.next(+1)
while value != 0:
value = self.counter.next(-1)
value = self.counter.next(+1)
def unlock(self):
self.counter.next(-1)
# -----------------------------------------------------------------------------
def test_counter():
vals = []
counter = Counter(MPI.COMM_WORLD)
for i in range(5):
c = counter.next()
vals.append(c)
counter.free()
vals = MPI.COMM_WORLD.allreduce(vals)
assert sorted(vals) == list(range(len(vals)))
def test_mutex():
mutex = Mutex(MPI.COMM_WORLD)
mutex.lock()
mutex.unlock()
mutex.free()
if __name__ == '__main__':
test_counter()
test_mutex()
# -----------------------------------------------------------------------------
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