Parser builder for common script arguments for Pattern Information Processing course assignments.

parser.py

#!/usr/bin/python2
"""
Parser builder for common script arguments.
"""

import argparse

import numpy as np


__all__ = ['target_fn', 'build_parser']


target_fn = dict(
    sin=np.sin,
    sin2=lambda x: np.sin(2*x),
    lin=lambda x: 2*x + 1,
    quad=lambda x: (x+1) * (x-2),
    cube=lambda x: (x+1) * (x-1) * (x-3),
    exp=np.exp
)


def build_parser():
    """Build argument parser for common script arguments."""

    # Build argument parser
    parser = argparse.ArgumentParser()

    # Learning-related arguments
    parser.add_argument('-N', '--sample-size', type=int, default=32,
                        help='Sample size')
    parser.add_argument('-l', '--lagrange-multiplier', type=float, default=0.1,
                        help='Lagrange multiplier')
    parser.add_argument('-b', '--bandwith-size', type=float, default=0.25,
                        help='Bandwith value for Gaussian kernel')
    parser.add_argument('-n', '--noise-level', type=float, default=0.05,
                        help='Maximum noise value')
    parser.add_argument('-f', '--target-function', type=str, default='sin',
                        choices=target_fn.keys(), help='Target function')
    parser.add_argument('-lc', '--lagrange-candidate', type=float, nargs='*',
                        help='Lagrange multipliers candidates to search')
    parser.add_argument('-bc', '--bandwith-candidate', type=float, nargs='*',
                        help='Bandwith size candidates to search')
    parser.add_argument('-k', '--num-fold', type=int, default=2,
                        help='Number of folds in cross-validation')
    parser.add_argument('--outlier', action='store_true',
                        help='Insert an outlier')

    # Drawing-related arguments
    parser.add_argument('--max-n', type=int, default=1024,
                        help='Maximum number of points to draw')
    parser.add_argument('-lb', '--left-bound', type=float, default=-5,
                        help='Left boundary of x-axis')
    parser.add_argument('-rb', '--right-bound', type=float, default=5,
                        help='Right boundary of x-axis')
    parser.add_argument('--show-legend', action='store_true',
                        help='Show legend in the plot')
    parser.add_argument('--save-as', type=str, default=None,
                        help='Filename to save')

    return parser