def load_center_of_mass(csv_file, row_start, col_start):
    """Load center of mass values into an array, where each index
    has the center of mass coordinates for a frame.

    Parameters
    ----------
    csv_file : string
        Filename of the csv file to be loaded.
    row_start : int
        Index of the first row in which center of mass data begins.
    col_start : int
        Index of the first column in which center of mass data begins.

    Returns
    -------
    center_of_mass : 2darray
        Array representation of the center of mass data.
    """
    infile = open(csv_file, 'r')
    center_of_mass = []
    lines = infile.readlines()
    for line in lines[row_start:]:
        formatted_line = line.strip().split(',')
        coordinates = formatted_line[col_start:col_start+3]
        coordinates = [float(x) for x in coordinates]
        center_of_mass.append(coordinates)
    infile.close()
    return center_of_mass