Source code for irfpy.swim.region

''' Region where the Moon is located.

Estimation by SWIM data.
Time is estimated from eye, and hard coded.
'''
import sympy

from irfpy.util import version as _v

# This module recommends sympy 1.5.1 or later
_v.recommends("1.5.1", sympy.__version__, "sympy")

def _get_empty_set():
    try:
        e = sympy.EmptySet()
    except TypeError:
        e = sympy.EmptySet

    return e


def interval_solarwind():
    ''' Return the orbit interval of the solar wind.

    The period is defined by eye.  It rejects when the s/c is umbiguous region.
    So this is rather solid solar wind region.

    :return: The intervals of the solar wind observation.
    :rtype: ``interval.IntervalSet``

    >>> insw = interval_solarwind()
    >>> 938 in insw
    True
    >>> 1111 in insw
    False
    >>> 3000 in insw
    True
    >>> 3800 in insw
    False
    '''
    intset = _get_empty_set()

    orb0 = [938, 1176, 1542, 1895, 2261, 2595, 2928]
    orb1 = [1066, 1426, 1786, 2144, 2485, 2822, 3136]

    for o0, o1 in zip(orb0, orb1):
        intvl = sympy.Interval(o0, o1)
        intset += intvl

    return intset