pycaffe训练的完整组件示例

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为什么写这篇博客

1. 需要用到pycaffe

因为用到的开源代码基于Caffe；要维护的项目基于Caffe。基本上是用Caffe的Python接口。

2. 训练中想穿插验证并输出关注的指标

比如每训练完1个epoch就应该在完整的validation集合上执行evaluation，输出测量出的、关注的指标，例如AP、Accuracy、F1-score等。Caffe通过solver.prototxt中配置test_net能执行测试，但基本只能输出Accuracy而且是各个test_batch上的平均Accuracy，而不是想关注的验证集整体上的AP（见Solver.cpp源码）

3. 训练中期望有可视化输出

Caffe训练输出在屏幕终端，也可自行重定向到日志文件。的确可以自行解析日志文件，并结合flask搭建web页面实时显示输出。但是这不够标准和鲁棒。期望有专门的可视化工具，避免自己造难用的轮子。

本文给出很简陋的pyCaffe和VisualDL结合的例子。

解决方案

用pycaffe接管训练接口

通过自行编写python代码来执行训练，而不是用$CAFFE_ROOT/build/tools/caffe train --solver solver.prototxt的方式来启动。

solver.prototxt中需要配置test_net, test_iter, test_interval，保证solver有test_net对象
test_interval设置为999999999，以避开Solver.cpp中执行的TestAll()函数，转而在python代码中手动判断和执行validation
执行validation之前注意test_net.share_with(train_net)
利用solver.step(1)执行训练网络的一次迭代，利用solver.test_net[0].forward()执行测试网络的一次前传
利用net.blobs['prob'].data的形式取出网络输出
利用sklearn.metrics包，将取出的数据执行evaluation
利用VisualDL等可视化工具，将取出的数据执行绘图

依赖项

VisualDL，是PaddlePaddle和ECharts团队联合推出的，应该是对抗谷歌的Tensorboarde的。相信ECharts的实力。

sudo pip install visualdl

看起来VisualDL和Tensorboard类似，不过对于Caffe，用不了Tensorboard，能用VisualDL也是好事。

参考代码

solve.py

#!/usr/bin/env python2 # coding: utf-8""" inspired and adapted from: - https://github.com/shelhamer/fcn.berkeleyvision.org - https://github.com/rbgirshick/py-faster-rcnn - https://github.com/PaddlePaddle/VisualDL/blob/develop/docs/quick_start_en.md """from __future__ import print_function import _init_paths import caffe import argparse import os import sys from datetime import datetime import cv2from caffe.proto import caffe_pb2 import google.protobuf as pb2 import google.protobuf.text_format import numpy as np import perfevalfrom visualdl import LogWriter #for visualization during trainingdef parse_args(): """Parse input arguments""" parser = argparse.ArgumentParser(description='Train a classification network') parser.add_argument('--solver', dest='solver', help='solver prototxt', default=None, type=str, required=True) parser.add_argument('--weights', dest='pretrained_model', help='initialize with pretrained model weights', default=None, type=str) if len(sys.argv) == 1: parser.print_help() sys.exit(1) args = parser.parse_args() return argsclass SolverWrapper: """对于Solver进行封装，便于外部调用""" def __init__(self, solver_prototxt, num_epoch, num_example, pretrained_model=None): self.solver = caffe.SGDSolver(solver_prototxt) if pretrained_model is not None: print('Loading pretrained model weights from {:s}'.format(pretrained_model)) self.solver.net.copy_from(pretrained_model) self.solver_param = caffe_pb2.SolverParameter() with open(solver_prototxt, 'rt') as f: pb2.text_format.Merge(f.read(), self.solver_param) self.cur_epoch = 0 self.test_interval = 100 #用来替代self.solver_param.test_interval self.logw = LogWriter("catdog_log", sync_cycle=100) with self.logw.mode('train') as logger: self.sc_train_loss = logger.scalar("loss") self.sc_train_acc = logger.scalar("Accuracy") with self.logw.mode('val') as logger: self.sc_val_acc = logger.scalar("Accuracy") self.sc_val_mAP = logger.scalar("mAP") def train_model(self): """执行训练的整个流程，穿插了validation""" cur_iter = 0 test_batch_size, num_classes = self.solver.test_nets[0].blobs['prob'].shape num_test_images_tot = test_batch_size * self.solver_param.test_iter[0] while cur_iter < self.solver_param.max_iter: #self.solver.step(self.test_interval) for i in range(self.test_interval): self.solver.step(1) loss = self.solver.net.blobs['loss'].data acc = self.solver.net.blobs['accuracy'].data step = self.solver.iter self.sc_train_loss.add_record(step, loss) self.sc_train_acc.add_record(step, acc) self.eval_on_val(num_classes, num_test_images_tot, test_batch_size) cur_iter += self.test_interval def eval_on_val(self, num_classes, num_test_images_tot, test_batch_size): """在整个验证集上执行inference和evaluation""" self.solver.test_nets[0].share_with(self.solver.net) self.cur_epoch += 1 scores = np.zeros((num_classes, num_test_images_tot), dtype=float) gt_labels = np.zeros((1, num_test_images_tot), dtype=float).squeeze() for t in range(self.solver_param.test_iter[0]): output = self.solver.test_nets[0].forward() probs = output['prob'] labels = self.solver.test_nets[0].blobs['label'].data gt_labels[t*test_batch_size:(t+1)*test_batch_size] = labels.T.astype(float) scores[:,t*test_batch_size:(t+1)*test_batch_size] = probs.T ap, acc = perfeval.cls_eval(scores, gt_labels) print('====================================================================\n') print('\tDo validation after the {:d}-th training epoch\n'.format(self.cur_epoch)) print('>>>>', end='\t') #设定标记，方便于解析日志获取出数据 for i in range(num_classes): print('AP[{:d}]={:.2f}'.format(i, ap[i]), end=', ') mAP = np.average(ap) print('mAP={:.2f}, Accuracy={:.2f}'.format(mAP, acc)) print('\n====================================================================\n') step = self.solver.iter self.sc_val_mAP.add_record(step, mAP) self.sc_val_acc.add_record(step, acc)if __name__ == '__main__': args = parse_args() solver_prototxt = args.solver num_epoch = args.num_epoch num_batch = args.num_batch pretrained_model = args.pretrained_model # init caffe.set_mode_gpu() caffe.set_device(0) sw = SolverWrapper(solver_prototxt, num_epoch, num_batch, pretrained_model) sw.train_model()

perfeval.py

#!/usr/bin/env python2 # coding: utf-8from __future__ import print_function import numpy as npimport sklearn.metrics as metricsdef cls_eval(scores, gt_labels): """ 分类任务的evaluation @param scores: cxmnp-array, m为样本数量(例如一个epoch) @param gt_labels: 1xm np-array, 元素属于{0,1,2,...,K-1}，表示K个类别的索引 """ num_classes, num_test_imgs = scores.shape pred_labels = scores.argmax(axis=0) ap = np.zeros((num_classes, 1), dtype=float).squeeze() for i in range(num_classes): cls_labels = np.zeros((1, num_test_imgs), dtype=float).squeeze() for j in range(num_test_imgs): if gt_labels[j]==i: cls_labels[j]=1 ap[i] = metrics.average_precision_score(cls_labels, scores[i]) acc = metrics.accuracy_score(gt_labels, pred_labels) return ap, acc

样例输出

首先需要开启训练，比如:

python solve.py

然后启动VisualDL：

visualDL --logdir=catdog_log --port=8080

打开浏览器获取训练的实时更新的绘图输出：http://localhost:8080。这里仅截图展示：