usage instructions

Creating algorithm has two main parts to it

• implementation
• testing

opalalgorithms provides you with utilities to do both.

implementation

We use opalalgorithms.core.base that provides utilities for implementing an algorithm for OPAL. An algorithm will look like as follows:

"""Sample algorithm 1 to return home of users."""
from __future__ import division, print_function
from opalalgorithms.core import OPALAlgorithm


class SampleAlgo1(OPALAlgorithm):
    """Calculate population density."""

    def __init__(self):
        """Initialize population density."""
        super(SampleAlgo1, self).__init__()

    def map(self, params, bandicoot_user):
        """Get home of the bandicoot user.

        Args:
            params (dict): Request parameters.
            bandicoot_user (bandicoot.core.User): Bandicoot user object.

        """
        home = bandicoot_user.recompute_home()
        if not home:
            return None
        return {getattr(home, params["resolution"]): 1}

testing

We provide utilities to test the algorithm you create. Before running the algorithm, it is advised you setup the apparmor and codejail as mentioned here.

Use tests/generate_data.py to generate data after installing the opalalgorithms library. You can run your algorithm with the following code:

"""Test population density algorithm."""
from __future__ import division, print_function
from opalalgorithms.utils import AlgorithmRunner


num_threads = 3
data_path = 'data'


def get_algo(filename):
    algorithm = dict(
        code=open(filename).read(),
        className='ClassNameOfYourAlgo'
    )
    return algorithm


def run_algo(algorithm_filename, params):
    """Run an algorithm."""
    algorithm = get_algo(algorithm_filename)
    algorunner = AlgorithmRunner(
        algorithm, dev_mode=False, multiprocess=True, sandboxing=True)
    result = algorunner(params, data_path, num_threads)
    return result


if __name__ == '__main__':
    """Test that algorithm runner runs successfully."""
    params = dict(
        sample=0.2,
        resolution='location_level_1')
    assert run_algo('/path/to/your/algo.py', params)