def nanotime(s=None):
    if s is not None:
        return int(s) * 1000000000
    return time.time() * 1000000000
3D filtering (i.e. convolution but without mirroring the filter).
dataset/ETHPy150Open benoitc/gaffer/gaffer/util.py/nanotime--crossover with--dataset/ETHPy150Open bbabenko/simple_convnet/simple_convnet/helpers.py/batch_filter3D