1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
#!/usr/bin/env python
"""
Parallel PI computation using Dynamic Process Management (DPM)
within Python objects exposing memory buffers (requires NumPy).
usage:
+ parent/child model::
$ mpiexec -n 1 python cpi-dpm.py [nchilds]
+ client/server model::
$ [xterm -e] mpiexec -n <nprocs> python cpi-dpm.py server [-v] &
$ [xterm -e] mpiexec -n 1 python cpi-dpm.py client [-v]
"""
import sys
from mpi4py import MPI
import numpy as N
def get_n():
prompt = "Enter the number of intervals: (0 quits) "
try:
n = int(input(prompt))
if n < 0: n = 0
except:
n = 0
return n
def view(pi, np=None, wt=None):
from math import pi as PI
prn = sys.stdout.write
if pi is not None:
prn("computed pi is: %.16f\n" % pi)
prn("absolute error: %.16f\n" % abs(pi - PI))
if np is not None:
prn("computing units: %d processes\n" % np)
if wt is not None:
prn("wall clock time: %g seconds\n" % wt)
sys.stdout.flush()
def comp_pi(n, comm, root=0):
nprocs = comm.Get_size()
myrank = comm.Get_rank()
n = N.array(n, 'i')
comm.Bcast([n, MPI.INT], root=root)
if n == 0: return 0.0
h = 1.0 / n;
s = 0.0;
for i in range(myrank, n, nprocs):
x = h * (i + 0.5);
s += 4.0 / (1.0 + x**2);
mypi = s * h
mypi = N.array(mypi, 'd')
pi = N.array(0, 'd')
comm.Reduce([mypi, MPI.DOUBLE],
[pi, MPI.DOUBLE],
root=root, op=MPI.SUM)
return pi
def master(icomm):
n = get_n()
wt = MPI.Wtime()
n = N.array(n, 'i')
icomm.Send([n, MPI.INT], dest=0)
pi = N.array(0, 'd')
icomm.Recv([pi, MPI.DOUBLE], source=0)
wt = MPI.Wtime() - wt
if n == 0: return
np = icomm.Get_remote_size()
view(pi, np, wt)
def worker(icomm):
myrank = icomm.Get_rank()
if myrank == 0:
source = dest = 0
else:
source = dest = MPI.PROC_NULL
n = N.array(0, 'i')
icomm.Recv([n, MPI.INT], source=source)
pi = comp_pi(n, comm=MPI.COMM_WORLD, root=0)
pi = N.array(pi, 'd')
icomm.Send([pi, MPI.DOUBLE], dest=dest)
# Parent/Child
def main_parent(nprocs=1):
assert nprocs > 0
assert MPI.COMM_WORLD.Get_size() == 1
icomm = MPI.COMM_WORLD.Spawn(command=sys.executable,
args=[__file__, 'child'],
maxprocs=nprocs)
master(icomm)
icomm.Disconnect()
def main_child():
icomm = MPI.Comm.Get_parent()
assert icomm != MPI.COMM_NULL
worker(icomm)
icomm.Disconnect()
# Client/Server
def main_server(COMM):
nprocs = COMM.Get_size()
myrank = COMM.Get_rank()
service, port, info = None, None, MPI.INFO_NULL
if myrank == 0:
port = MPI.Open_port(info)
log(COMM, "open port '%s'", port)
service = 'cpi'
MPI.Publish_name(service, port, info)
log(COMM, "service '%s' published.", service)
else:
port = ''
log(COMM, "waiting for client connection ...")
icomm = COMM.Accept(port, info, root=0)
log(COMM, "client connection accepted.")
worker(icomm)
log(COMM, "disconnecting from client ...")
icomm.Disconnect()
log(COMM, "client disconnected.")
if myrank == 0:
MPI.Unpublish_name(service, port, info)
log(COMM, "service '%s' unpublished", port)
MPI.Close_port(port)
log(COMM, "closed port '%s' ", port)
def main_client(COMM):
assert COMM.Get_size() == 1
service, info = 'cpi', MPI.INFO_NULL
port = MPI.Lookup_name(service, info)
log(COMM, "service '%s' found in port '%s'.", service, port)
log(COMM, "connecting to server ...")
icomm = COMM.Connect(port, info, root=0)
log(COMM, "server connected.")
master(icomm)
log(COMM, "disconnecting from server ...")
icomm.Disconnect()
log(COMM, "server disconnected.")
def main():
assert len(sys.argv) <= 2
if 'server' in sys.argv:
main_server(MPI.COMM_WORLD)
elif 'client' in sys.argv:
main_client(MPI.COMM_WORLD)
elif 'child' in sys.argv:
main_child()
else:
try: nchilds = int(sys.argv[1])
except: nchilds = 2
main_parent(nchilds)
VERBOSE = False
def log(COMM, fmt, *args):
if not VERBOSE: return
if COMM.rank != 0: return
sys.stdout.write(fmt % args)
sys.stdout.write('\n')
sys.stdout.flush()
if __name__ == '__main__':
if '-v' in sys.argv:
VERBOSE = True
sys.argv.remove('-v')
main()
|
