最近在研究模型的计算量，发现Pytorch有库可以直接计算模型的计算量，所以需要一个一个Keras和Tensorflow可以用的，直接把Model接入到函数中，print一下就可以计算出FLOPs

       FLOPS：注意全大写，是floating point operations per second的缩写，意指每秒浮点运算次数，理解为计算速度。是一个衡量硬件性能的指标。

        FLOPs：注意s小写，是floating point operations的缩写（s表复数），意指浮点运算数，理解为计算量。可以用来衡量算法/模型的复杂度。

      对于计算量主要有Madds和MFlops两个概念。shufflenet的论文用的是Flops，Mobilenet用的是Madds，Flops应该是Madds的两倍，具体可参考

  https://blog.csdn.net/shwan_ma/article/details/84924142

   https://www.zhihu.com/question/65305385/answer/451060549

  计算函数如下：

import tensorflow as tf
import keras.backend as K


def get_flops(model):
    run_meta = tf.RunMetadata()
    opts = tf.profiler.ProfileOptionBuilder.float_operation()

    # We use the Keras session graph in the call to the profiler.
    flops = tf.profiler.profile(graph=K.get_session().graph,
                                run_meta=run_meta, cmd='op', options=opts)

    return flops.total_float_ops  # Prints the "flops" of the model.


# .... Define your model here ....
print(get_flops(model))

  贴一个Mask_RCNN的计算结果

Doc:
op: The nodes are operation kernel type, such as MatMul, Conv2D. Graph nodes belonging to the same type are aggregated together.
flops: Number of float operations. Note: Please read the implementation for the math behind it.

Profile:
node name | # float_ops
Conv2D                   95.74b float_ops (100.00%, 90.16%)
Conv2DBackpropInput      10.28b float_ops (9.84%, 9.68%)
Mul                      63.89m float_ops (0.16%, 0.06%)
Add                      63.88m float_ops (0.10%, 0.06%)
BiasAdd                  46.49m float_ops (0.04%, 0.04%)
ArgMax                   80.00k float_ops (0.00%, 0.00%)
Minimum                  4.10k float_ops (0.00%, 0.00%)
Maximum                  4.10k float_ops (0.00%, 0.00%)
Sub                      2.33k float_ops (0.00%, 0.00%)
GreaterEqual             1.00k float_ops (0.00%, 0.00%)
Greater                  1.00k float_ops (0.00%, 0.00%)
Equal                      400 float_ops (0.00%, 0.00%)
RealDiv                    202 float_ops (0.00%, 0.00%)
Log                        102 float_ops (0.00%, 0.00%)
Less                         2 float_ops (0.00%, 0.00%)