pySNoW: A Python interface to SNoW

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pySnow is a minimal python interface to the SNoW - Sparse Network of Winnows learning architecture. It is meant to be faithful to the original command line interface and provides access to the train, test, evaluate, interactive and server modes directly from python. pySnow requires SNoW version 3.2.0. Please report any questions or problems to nnshah2@uiuc.edu.

The pySnow module provides 3 functions (train, test, evaluate) and 1 type SnowSession) corresponding to the different modes of the original command line SNoW.

Functions

`train(args)`

Equivalent to running SNoW in training mode. Command line arguments are passed in as a dictionary of key,value pairs. In addition to the supported output modes of SNoW the command can also redirect output to a string that is returned as the result of the command. This is the default.

Example:

## original snow command:
## ../snow -train -I $train_file -F $net_file -A $arch_file
## becomes:

import snow
args = {'I':train_file, 'F':net_file, 'A':arch_file}
result = snow.train(args)

`test(args)`

Equivalent to running SNoW in testing mode. Command line arguments are passed in as a dictionary of key,value pairs. In addition to the supported output modes of SNoW the command can also redirect output to a string that is returned as the result of the command. This is the default.

Example:

## original snow command:
## ../snow -test -I $test_file -F $net_file 
## becomes:

import snow
args = {'I':test_file, 'F':net_file}
result = snow.test(args)

evaluate(args)

Equivalent to running SNoW in evaluate mode. Command line arguments are passed in as a dictionary of key,value pairs. In addition to the supported output modes of SNoW the command can also redirect output to a string that is returned as the result of the command. This is the default.

SnowSession

In addition to the basic "one-shot" modes described above pySnow also provides an interface to SNoW's "interactive" and "server" modes through the SnowSession type. The SnowSession constructor takes two arguments, the runMode and the command line arguments (as above). SnowSession provides two methods "update" (for interactive mode) and "evaluateExample" (for server mode).

Interactive Mode

To use SNoW's interactive mode, instantiate SnowSession type as follows:

args = {'I':test_file, 'F':net_file}
session = snow.SnowSession(snow.MODE_INTERACTIVE,args)

To update the network or evaluate an example use the "update" method:

testdata = open(test_file,"r")
for ex in testdata:
      result=session.update('e,'+ex)
      print result

Server Mode

To use SNoW's server mode, instantiate SnowSession type as follows:

args = {'I':test_file, 'F':net_file}
session = snow.SnowSession(snow.MODE_SERVER,args)

To evaluate an example use the "evaluateExample" method:

testdata = open(test_file,"r")
for ex in testdata:
      result=session.evaluateExample(ex)
      print result

Note while this mode has the semantics of the traditional server mode, there is no socket communication and no additional thread.

Participants:

Neelay Shah