import math


def float_range(a, b, inc):
    """
    Returns a list containing an arithmetic progression of floats.
    This is simply a float version of the built-in range(a, b, step)
    function.  The result is [ , ) as always in Python.
    """
    try:
        x = [float(a)]
    except:
        raise ValueError("float value required")
    for i in range(1, int(math.ceil((b - a ) / inc))):
        x.append(a + i * inc)
    return x