Overview

The map function is well-known in Python, allowing a single function to be called on each member of an iterable sequence:

map( function, [1,2,3,4] )

The seppo module allows the same functionality, but distributed over several processes:

seppo.map_parallel( some_module.function, [1,2,3,4] )

In this case, each iteration may evaluate the function in a different process, possibly in a different computer. The idea is a simple concept and is hopefully natural transition for Python programmers to use the power of multi-processor computers and clusters.

Currently, seppo is based on Pyro mobile code and is subject to the same caveats. To understand these issues, please read about Pyro mobile code.

An example

The following example is included with seppo.

The main program (simple.py):

import seppo
import example_module

results = seppo.map_parallel(example_module.hello_world, [1,2,3,4,5])

for result in results:
    print result

Here is the function that does the work. Note, this function must be in a separate module, due to a limitation of Pyro mobile code. (example_module.py):

import socket, os

def hello_world( value ):
    value2 = value*value
    fqdn = socket.getfqdn()
    pid = os.getpid()
    host_str = "%s, process %d"%(fqdn,pid)
    result = 'hello world from %s (input=%f, value*value=%f)'%(host_str,value,value2)
    return result

And to start a server (serv_a_process.py):

import seppo
seppo.start_seppo_enslaved_server()

The sequence to run this example:

• Start a Pyro name server
• Run the server(s) (python serv_a_process.py)
• Run the client (python simple.py)

The above should produce output something like the following if there are 2 servers running:

$ python simple.py

hello world from host1, process 23759 (input=1.000000, value*value=1.000000)
hello world from host1, process 23759 (input=2.000000, value*value=4.000000)
hello world from host1, process 23759 (input=3.000000, value*value=9.000000)
hello world from host2, process 9832 (input=4.000000, value*value=16.000000)
hello world from host2, process 9832 (input=5.000000, value*value=25.000000)

Warning - run only on a secure network

Because seppo works by allowing arbitrary Python code on your machine via an open network port, you must make absolutely sure your network is secure. Seppo does absolutely nothing in terms of security.

Download

Grab it from the download directory.

There is an online changelog and CHANGELOG.txt in the source distribution describing each release.

Seppo works as described above, but hasn't yet seen much use. This should be considered a very alpha version, and was released to the public to gauge interest/reaction.

License

BSD license. See the file LICENSE.txt distributed with the source code.

Copyright owner and author: Andrew Straw