介紹
gluon把mxnet再進行封裝，封裝的風格非常接近pytorch
使用gluon的好處是非常容易把pytorch模型向mxnet轉化
唯一的問題是gluon封裝還不成熟，封裝好的layer不多，很多常用的layer 如concat,upsampling等layer都沒有
這裏關注如何把pytorch 模型快速轉換成 mxnet基於symbol 和 exector設計的網絡
pytorch轉mxnet module
關鍵點:
- mxnet 設計網絡時symbol 名稱要和pytorch初始化中各網絡層名稱對應
- torch.load()讀入pytorch模型checkpoint 字典，取當中的'state_dict'元素，也是一個字典
- pytorch state_dict 字典中key是網絡層參數的名稱，val是參數ndarray
- pytorch 的參數名稱的組織形式和mxnet一樣，但是連接符號不同，pytorch是'.'，而mxnet是'_'比如：
pytorch '0.conv1.0.weight'
mxnet '0_conv1_0_weight'
- pytorch 的參數array 和mxnet 的參數array 完全一樣，只要名稱對上，直接賦值即可初始化mxnet模型
需要做的有以下幾點：
- 設計和pytorch網絡對應的mxnet網絡
- 加載pytorch checkpoint
- 調整pytorch checkpoint state_dict 的key名稱和mxnet命名格式一致
FlowNet2S PytorchToMxnet
pytorch flownet2S 的checkpoint 可以在github上搜到
import mxnet as mx
from symbol_util import *
import pickle
def get_loss(data, label, loss_scale, name, get_input=False, is_sparse = False, type='stereo'):
if type == 'stereo':
data = mx.sym.Activation(data=data, act_type='relu',name=name+'relu')
# loss
if is_sparse:
loss =mx.symbol.Custom(data=data, label=label, name=name, loss_scale= loss_scale, is_l1=True,
op_type='SparseRegressionLoss')
else:
loss = mx.sym.MAERegressionOutput(data=data, label=label, name=name, grad_scale=loss_scale)
return (loss,data) if get_input else loss
def flownet_s(loss_scale, is_sparse=False, name=''):
img1 = mx.symbol.Variable('img1')
img2 = mx.symbol.Variable('img2')
data = mx.symbol.concat(img1,img2,dim=1)
labels = {'loss{}'.format(i): mx.sym.Variable('loss{}_label'.format(i)) for i in range(0, 7)}
# print('labels: ',labels)
prediction = {}# a dict for loss collection
loss = []#a list
#normalize
data = (data-125)/255
# extract featrue
conv1 = mx.sym.Convolution(data, pad=(3, 3), kernel=(7, 7), stride=(2, 2), num_filter=64, name=name + 'conv1_0')
conv1 = mx.sym.LeakyReLU(data=conv1, act_type='leaky', slope=0.1)
conv2 = mx.sym.Convolution(conv1, pad=(2, 2), kernel=(5, 5), stride=(2, 2), num_filter=128, name=name + 'conv2_0')
conv2 = mx.sym.LeakyReLU(data=conv2, act_type='leaky', slope=0.1)
conv3a = mx.sym.Convolution(conv2, pad=(2, 2), kernel=(5, 5), stride=(2, 2), num_filter=256, name=name + 'conv3_0')
conv3a = mx.sym.LeakyReLU(data=conv3a, act_type='leaky', slope=0.1)
conv3b = mx.sym.Convolution(conv3a, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=256, name=name + 'conv3_1_0')
conv3b = mx.sym.LeakyReLU(data=conv3b, act_type='leaky', slope=0.1)
conv4a = mx.sym.Convolution(conv3b, pad=(1, 1), kernel=(3, 3), stride=(2, 2), num_filter=512, name=name + 'conv4_0')
conv4a = mx.sym.LeakyReLU(data=conv4a, act_type='leaky', slope=0.1)
conv4b = mx.sym.Convolution(conv4a, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=512, name=name + 'conv4_1_0')
conv4b = mx.sym.LeakyReLU(data=conv4b, act_type='leaky', slope=0.1)
conv5a = mx.sym.Convolution(conv4b, pad=(1, 1), kernel=(3, 3), stride=(2, 2), num_filter=512, name=name + 'conv5_0')
conv5a = mx.sym.LeakyReLU(data=conv5a, act_type='leaky', slope=0.1)
conv5b = mx.sym.Convolution(conv5a, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=512, name=name + 'conv5_1_0')
conv5b = mx.sym.LeakyReLU(data=conv5b, act_type='leaky', slope=0.1)
conv6a = mx.sym.Convolution(conv5b, pad=(1, 1), kernel=(3, 3), stride=(2, 2), num_filter=1024, name=name + 'conv6_0')
conv6a = mx.sym.LeakyReLU(data=conv6a, act_type='leaky', slope=0.1)
conv6b = mx.sym.Convolution(conv6a, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=1024,
name=name + 'conv6_1_0')
conv6b = mx.sym.LeakyReLU(data=conv6b, act_type='leaky', slope=0.1, )
#predict flow
pr6 = mx.sym.Convolution(conv6b, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=2,
name=name + 'predict_flow6')
prediction['loss6'] = pr6
upsample_pr6to5 = mx.sym.Deconvolution(pr6, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=2,
name=name + 'upsampled_flow6_to_5', no_bias=True)
upconv5 = mx.sym.Deconvolution(conv6b, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=512,
name=name + 'deconv5_0', no_bias=False)
upconv5 = mx.sym.LeakyReLU(data=upconv5, act_type='leaky', slope=0.1)
iconv5 = mx.sym.Concat(conv5b, upconv5, upsample_pr6to5, dim=1)
pr5 = mx.sym.Convolution(iconv5, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=2,
name=name + 'predict_flow5')
prediction['loss5'] = pr5
upconv4 = mx.sym.Deconvolution(iconv5, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=256,
name=name + 'deconv4_0', no_bias=False)
upconv4 = mx.sym.LeakyReLU(data=upconv4, act_type='leaky', slope=0.1)
upsample_pr5to4 = mx.sym.Deconvolution(pr5, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=2,
name=name + 'upsampled_flow5_to_4', no_bias=True)
iconv4 = mx.sym.Concat(conv4b, upconv4, upsample_pr5to4)
pr4 = mx.sym.Convolution(iconv4, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=2,
name=name + 'predict_flow4')
prediction['loss4'] = pr4
upconv3 = mx.sym.Deconvolution(iconv4, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=128,
name=name + 'deconv3_0', no_bias=False)
upconv3 = mx.sym.LeakyReLU(data=upconv3, act_type='leaky', slope=0.1)
upsample_pr4to3 = mx.sym.Deconvolution(pr4, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=2,
name= name + 'upsampled_flow4_to_3', no_bias=True)
iconv3 = mx.sym.Concat(conv3b, upconv3, upsample_pr4to3)
pr3 = mx.sym.Convolution(iconv3, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=2,
name=name + 'predict_flow3')
prediction['loss3'] = pr3
upconv2 = mx.sym.Deconvolution(iconv3, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=64,
name=name + 'deconv2_0', no_bias=False)
upconv2 = mx.sym.LeakyReLU(data=upconv2, act_type='leaky', slope=0.1)
upsample_pr3to2 = mx.sym.Deconvolution(pr3, pad=(1, 1), kernel=(4, 4), stride=(2, 2), num_filter=2,
name=name + 'upsampled_flow3_to_2', no_bias=True)
iconv2 = mx.sym.Concat(conv2, upconv2, upsample_pr3to2)
pr2 = mx.sym.Convolution(iconv2, pad=(1, 1), kernel=(3, 3), stride=(1, 1), num_filter=2,
name=name + 'predict_flow2')
prediction['loss2'] = pr2
flow = mx.sym.UpSampling(arg0=pr2,scale=4,num_filter=2,num_args = 1,sample_type='nearest', name='upsample_flow2_to_1')
# ignore the loss functions with loss scale of zero
keys = loss_scale.keys()
# keys.sort()
#obtain the symbol of the losses
for key in keys:
# loss.append(get_loss(prediction[key] * 20, labels[key], loss_scale[key], name=key + name,get_input=False, is_sparse=is_sparse, type='flow'))
loss.append(mx.sym.MAERegressionOutput(data=prediction[key] * 20, label=labels[key], name=key + name, grad_scale=loss_scale[key]))
# print('loss: ',loss)
#group 暫時不知道爲嘛要group
loss_group =mx.sym.Group(loss)
# print('net: ',loss_group)
return loss_group,flow
import gluonbook as gb
import torch
from utils.frame_utils import *
import numpy as np
if __name__ == '__main__':
checkpoint = torch.load("C:/Users/junjie.huang/PycharmProjects/flownet2_mxnet/flownet2_pytorch/FlowNet2-S_checkpoint.pth.tar")
# # checkpoint是一個字典
print(isinstance(checkpoint['state_dict'], dict))
# # 打印checkpoint字典中的key名
print('keys of checkpoint:')
for i in checkpoint:
print(i)
print('')
# # pytorch 模型參數保存在一個key名爲'state_dict'的元素中
state_dict = checkpoint['state_dict']
# # state_dict也是一個字典
print('keys of state_dict:')
for i in state_dict:
print(i)
# print(state_dict[i].size())
print('')
# print(state_dict)
#字典的value是torch.tensor
print(torch.is_tensor(state_dict['conv1.0.weight']))
#查看某個value的size
print(state_dict['conv1.0.weight'].size())
#flownet-mxnet init
loss_scale={'loss2': 1.00,
'loss3': 1.00,
'loss4': 1.00,
'loss5': 1.00,
'loss6': 1.00}
loss,flow = flownet_s(loss_scale=loss_scale,is_sparse=False)
print('loss information: ')
print('loss:',loss)
print('type:',type(loss))
print('list_arguments:',loss.list_arguments())
print('list_outputs:',loss.list_outputs())
print('list_inputs:',loss.list_inputs())
print('')
print('flow information: ')
print('flow:',flow)
print('type:',type(flow))
print('list_arguments:',flow.list_arguments())
print('list_outputs:',flow.list_outputs())
print('list_inputs:',flow.list_inputs())
print('')
name_mxnet = symbol.list_arguments()
print(type(name_mxnet))
for key in name_mxnet:
print(key)
name_mxnet.sort()
for key in name_mxnet:
print(key)
print(name_mxnet)
shapes = (1, 3, 384, 512)
ctx = gb.try_gpu()
# exe = symbol.simple_bind(ctx=ctx, img1=shapes,img2=shapes)
exe = flow.simple_bind(ctx=ctx, img1=shapes, img2=shapes)
print('exe type: ',type(exe))
print('exe: ',exe)
#module
# mod = mx.mod.Module(flow)
# print('mod type: ', type(exe))
# print('mod: ', exe)
pim1 = read_gen("C:/Users/junjie.huang/PycharmProjects/flownet2_mxnet/data/0000007-img0.ppm")
pim2 = read_gen("C:/Users/junjie.huang/PycharmProjects/flownet2_mxnet/data/0000007-img1.ppm")
print(pim1.shape)
'''使用pytorch 的state_dict 初始化 mxnet 模型參數'''
for key in state_dict:
# print(type(key))
k_split = key.split('.')
key_mx = '_'.join(k_split)
# print(key,key_mx)
try:
exe.arg_dict[key_mx][:]=state_dict[key].data
except:
print(key,exe.arg_dict[key_mx].shape,state_dict[key].data.shape)
exe.arg_dict['img1'][:] = pim1[np.newaxis, :, :, :].transpose(0, 3, 1, 2).data
exe.arg_dict['img2'][:] = pim2[np.newaxis, :, :, :].transpose(0, 3, 1, 2).data
result = exe.forward()
print('result: ',type(result))
# for tmp in result:
# print(type(tmp))
# print(tmp.shape)
# color = flow2color(exe.outputs[0].asnumpy()[0].transpose(1, 2, 0))
outputs = exe.outputs
print('output type: ',type(outputs))
# for tmp in outputs:
# print(type(tmp))
# print(tmp.shape)
#來自pytroch flownet2
from visualize import flow2color
# color = flow2color(exe.outputs[0].asnumpy()[0].transpose(1,2,0))
flow_color = flow2color(exe.outputs[0].asnumpy()[0].transpose(1, 2, 0))
print('color type:',type(flow_color))
import matplotlib.pyplot as plt
#來自pytorch
from torchvision.transforms import ToPILImage
TF = ToPILImage()
images = TF(flow_color)
images.show()
# plt.imshow(color)