# HG changeset patch
# User paulb
# Date 1189815125 0
# Node ID df9f7a4e712b47e5dfdf09add8391c8a0b05f055
# Parent  36f4afc7748a127b82f4dc622d89fe77a796c830
[project @ 2007-09-15 00:12:05 by paulb]
Added examples using the create method on exchanges and the Queue class.
Fixed the limit in the pmap example.

diff -r 36f4afc7748a -r df9f7a4e712b examples/simple_create.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/simple_create.py	Sat Sep 15 00:12:05 2007 +0000
@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+
+"""
+A simple example of parallel computation using message exchanges and the create
+function.
+"""
+
+import pprocess
+import time
+
+# Array size and a limit on the number of processes.
+
+N = 10
+limit = 10
+delay = 1
+
+# Monitoring class.
+
+class MyExchange(pprocess.Exchange):
+
+    "Parallel convenience class containing the array assignment operation."
+
+    def store_data(self, ch):
+        i, j, result = ch.receive()
+        self.D[i*N+j] = result
+
+# Main program.
+
+if __name__ == "__main__":
+
+    # Initialise the communications exchange with a limit on the number of
+    # channels/processes.
+
+    exchange = MyExchange(limit=limit)
+    t = time.time()
+
+    # Initialise an array - it is stored in the exchange to permit automatic
+    # assignment of values as the data arrives.
+
+    exchange.D = [0] * N * N
+
+    # The parallel computation.
+    # NOTE: Could use the with statement in the loop to package the
+    # NOTE: try...finally functionality.
+
+    print "Calculating..."
+    for i in range(0, N):
+        for j in range(0, N):
+            ch = exchange.create()
+            if ch:
+                try: # Calculation work.
+
+                    time.sleep(delay)
+                    ch.send((i, j, i * N + j))
+
+                finally: # Important finalisation.
+
+                    pprocess.exit(ch)
+
+    print "Finishing..."
+    exchange.finish()
+
+    # Show the result.
+
+    print "Time taken:", time.time() - t
+    for i in range(0, N):
+        for result in exchange.D[i*N:i*N+N]:
+            print result,
+        print
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r 36f4afc7748a -r df9f7a4e712b examples/simple_pmap.py
--- a/examples/simple_pmap.py	Sat Sep 15 00:11:23 2007 +0000
+++ b/examples/simple_pmap.py	Sat Sep 15 00:12:05 2007 +0000
@@ -10,7 +10,7 @@
 # Array size and a limit on the number of processes.
 
 N = 10
-limit = 20
+limit = 10
 delay = 1
 
 # Work function.
diff -r 36f4afc7748a -r df9f7a4e712b examples/simple_queue.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/simple_queue.py	Sat Sep 15 00:12:05 2007 +0000
@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+
+"""
+A simple example of parallel computation using message queues and the create
+function.
+"""
+
+import pprocess
+import time
+
+# Array size and a limit on the number of processes.
+
+N = 10
+limit = 10
+delay = 1
+
+# Main program.
+
+if __name__ == "__main__":
+
+    # Initialise the communications queue with a limit on the number of
+    # channels/processes.
+
+    queue = pprocess.Queue(limit=limit)
+    t = time.time()
+
+    # Initialise an array.
+
+    D = [0] * N * N
+
+    # The parallel computation.
+    # NOTE: Could use the with statement in the loop to package the
+    # NOTE: try...finally functionality.
+
+    print "Calculating..."
+    for i in range(0, N):
+        for j in range(0, N):
+            ch = queue.create()
+            if ch:
+                try: # Calculation work.
+
+                    time.sleep(delay)
+                    ch.send((i, j, i * N + j))
+
+                finally: # Important finalisation.
+
+                    pprocess.exit(ch)
+
+    print "Finishing..."
+    for i, j, result in queue:
+        D[i*N+j] = result
+
+    # Show the result.
+
+    print "Time taken:", time.time() - t
+    for i in range(0, N):
+        for result in D[i*N:i*N+N]:
+            print result,
+        print
+
+# vim: tabstop=4 expandtab shiftwidth=4