"""
Various useful utilities (duh)
"""

import numpy as np

def sampled_time(sample_rate=1, start=0, end=1, offset=0):
    return offset + np.arange(start, end, 1/sample_rate)

def rot_vector(phi1=0.12345):
    """
    Return a unit vector rotated by phi radians.
    """

    unit = np.array([
                phi1,
                phi1 - np.pi/2
            ])

    return np.cos(unit)