def nb_per_chunk(item_size, item_dim, chunk_size):
    """Return the number of items that can be stored in one chunk.

    :param int item_size: Size of an item's scalar componant in
        Bytes (e.g. for np.float64 this is 8)

    :param int item_dim: Items dimension (length of the second axis)

    :param float chunk_size: The size of a chunk given in MBytes.

    """
    size = chunk_size * 10.0 ** 6
    ratio = int(round(size / (item_size * item_dim)))
    return max(10, ratio)
