def prepare_pt_context(num_gpus,
                       batch_size):
    """
    Correct batch size.

    Parameters
    ----------
    num_gpus : int
        Number of GPU.
    batch_size : int
        Batch size for each GPU.

    Returns
    -------
    bool
        Whether to use CUDA.
    int
        Batch size for all GPUs.
    """
    use_cuda = (num_gpus > 0)
    batch_size *= max(1, num_gpus)
    return use_cuda, batch_size