util.py

from math import *

def format_number(n, accuracy=6):
    """Formats a number in a friendly manner
    (removes trailing zeros and unneccesary point."""

    fs = "%."+str(accuracy)+"f"
    str_n = fs%float(n)
    if '.' in str_n:
        str_n = str_n.rstrip('0').rstrip('.')
    if str_n == "-0":
        str_n = "0"
    #str_n = str_n.replace("-0", "0")
    return str_n


def lerp(a, b, i):
    """Linear enterpolate from a to b."""
    return a+(b-a)*i


def range2d(range_x, range_y):

    """Creates a 2D range."""

    range_x = list(range_x)
    return [ (x, y) for y in range_y for x in range_x ]


def xrange2d(range_x, range_y):

    """Iterates over a 2D range."""

    range_x = list(range_x)
    for y in range_y:
        for x in range_x:
            yield (x, y)


def saturate(value, low, high):
    return min(max(value, low), high)


def is_power_of_2(n):
    """Returns True if a value is a power of 2."""
    return log(n, 2) % 1.0 == 0.0


def next_power_of_2(n):
    """Returns the next power of 2 that is >= n"""
    return int(2 ** ceil(log(n, 2)))

if __name__ == "__main__":

    print (list( xrange2d(xrange(3), xrange(3)) ))
    print (range2d(xrange(3), xrange(3)))
    print (is_power_of_2(7))
    print (is_power_of_2(8))
    print (is_power_of_2(9))

    print (next_power_of_2(7))