官方教程，講的還行，我用自己的實例講解。自己如何設計網絡，自己的迭代器

1：引入module：

import mxnet as mx import numpy as np import cv2 import matplotlib.pyplot as plt import logginglogger = logging.getLogger() logger.setLevel(logging.DEBUG)

2：創建網絡：

# Variables are place holders for input arrays. We give each variable a unique name. data = mx.symbol.Variable('data')# The input is fed to a fully connected layer that computes Y=WX+b. # This is the main computation module in the network. # Each layer also needs an unique name. We'll talk more about naming in the next section. fc1 = mx.symbol.FullyConnected(data = data, name='fc1', num_hidden=128) # Activation layers apply a non-linear function on the previous layer's output. # Here we use Rectified Linear Unit (ReLU) that computes Y = max(X, 0). act1 = mx.symbol.Activation(data = fc1, name='relu1', act_type="relu")fc2 = mx.symbol.FullyConnected(data = act1, name = 'fc2', num_hidden = 64) act2 = mx.symbol.Activation(data = fc2, name='relu2', act_type="relu")fc3 = mx.symbol.FullyConnected(data = act2, name='fc3', num_hidden=10) # Finally we have a loss layer that compares the network's output with label and generates gradient signals. mlp = mx.symbol.SoftmaxOutput(data = fc3, name = 'softmax')

3：顯示網絡：

mx.viz.plot_network(mlp)

不過這個在spyder上無法顯示，所以本人使用這個，會在運行目錄下創建jpg的圖：

mx.viz.plot_network(mlp).view()

4：加載數據：

由于官方mxnet只用mnist數據來測試，所以：

又由于data很難下下來，所以在example目錄下新建data文件夾，在data文件夾中創建mldata文件夾，再放入從github上下載的original_mnist.mat文件

from sklearn.datasets import fetch_mldata import os,sys curr_path = sys.path[0] sys.path = [os.path.join("/home/hu/mxnet-master/example/autoencoder")] + sys.path import data X,Y=data.get_mnist()for i in range(10):plt.subplot(1,10,i+1)plt.imshow(X[i].reshape((28,28)), cmap='Greys_r')plt.axis('off') plt.show()X = X.astype(np.float32)/255 X_train = X[:60000] X_test = X[60000:] Y_train = Y[:60000] Y_test = Y[60000:]

5：設置數據迭代器：

mxnet這個數據迭代器創建可以自己寫函數，網上可以查得到，mxnet工作其實就是數據一塊一塊的迭代

batch_size = 100 train_iter = mx.io.NDArrayIter(X_train, Y_train, batch_size=batch_size) test_iter = mx.io.NDArrayIter(X_test, Y_test, batch_size=batch_size)

6：訓練：

網上看到，好像不要這樣去訓練，因為這樣的話，你能夠調試的東西就少了

model = mx.model.FeedForward(ctx = mx.gpu(0), # Run on GPU 0symbol = mlp, # Use the network we just definednum_epoch = 10, # Train for 10 epochslearning_rate = 0.1, # Learning ratemomentum = 0.9, # Momentum for SGD with momentumwd = 0.00001) # Weight decay for regularization model.fit(X=train_iter, # Training data seteval_data=test_iter, # Testing data set. MXNet computes scores on test set every epochbatch_end_callback = mx.callback.Speedometer(batch_size, 200)) # Logging module to print out progress

第二種：

先把數據放入顯存，初始化參數，然后在訓練（貌似，用這個準確率更高？）

data = mx.symbol.Variable('data') fc1 = mx.symbol.FullyConnected(data, name='fc1', num_hidden=128) act1 = mx.symbol.Activation(fc1, name='relu1', act_type="relu") fc2 = mx.symbol.FullyConnected(act1, name = 'fc2', num_hidden = 64) act2 = mx.symbol.Activation(fc2, name='relu2', act_type="relu") fc3 = mx.symbol.FullyConnected(act2, name='fc3', num_hidden=10) out = mx.symbol.SoftmaxOutput(fc3, name = 'softmax') # construct the module mod = mx.mod.Module(out,context=mx.gpu()) mod.bind(data_shapes=train_iter.provide_data,label_shapes=train_iter.provide_label) mod.init_params() mod.fit(train_iter, eval_data=test_iter,optimizer_params={'learning_rate':0.01, 'momentum': 0.9},num_epoch=10)

?

7：用訓練好的模型進行來預測：

plt.imshow((X_test[0].reshape((28,28))*255).astype(np.uint8), cmap='Greys_r') plt.show() print 'Result:', model.predict(X_test[0:1])[0].argmax()

8：有模型評估函數：

print 'Accuracy:', model.score(test_iter)*100, '%'

9：弄成網頁調用函數：

# run hand drawing test from IPython.display import HTMLdef classify(img):img = img[len('data:image/png;base64,'):].decode('base64')img = cv2.imdecode(np.fromstring(img, np.uint8), -1)img = cv2.resize(img[:,:,3], (28,28))img = img.astype(np.float32).reshape((1, 784))/255.0return model.predict(img)[0].argmax()html = """<style type="text/css">canvas { border: 1px solid black; }</style><div id="board"><canvas id="myCanvas" width="100px" height="100px">Sorry, your browser doesn't support canvas technology.</canvas><p><button id="classify" οnclick="classify()">Classify</button><button id="clear" οnclick="myClear()">Clear</button>Result: <input type="text" id="result_output" size="5" value=""></p></div>""" script = """<script type="text/JavaScript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js?ver=1.4.2"></script><script type="text/javascript">function init() {var myCanvas = document.getElementById("myCanvas");var curColor = $('#selectColor option:selected').val();if(myCanvas){var isDown = false;var ctx = myCanvas.getContext("2d");var canvasX, canvasY;ctx.lineWidth = 5;$(myCanvas).mousedown(function(e){isDown = true;ctx.beginPath();var parentOffset = $(this).parent().offset(); canvasX = e.pageX - parentOffset.left;canvasY = e.pageY - parentOffset.top;ctx.moveTo(canvasX, canvasY);}).mousemove(function(e){if(isDown != false) {var parentOffset = $(this).parent().offset(); canvasX = e.pageX - parentOffset.left;canvasY = e.pageY - parentOffset.top;ctx.lineTo(canvasX, canvasY);ctx.strokeStyle = curColor;ctx.stroke();}}).mouseup(function(e){isDown = false;ctx.closePath();});}$('#selectColor').change(function () {curColor = $('#selectColor option:selected').val();});}init();function handle_output(out) {document.getElementById("result_output").value = out.content.data["text/plain"];}function classify() {var kernel = IPython.notebook.kernel;var myCanvas = document.getElementById("myCanvas");data = myCanvas.toDataURL('image/png');document.getElementById("result_output").value = "";kernel.execute("classify('" + data +"')", { 'iopub' : {'output' : handle_output}}, {silent:false});}function myClear() {var myCanvas = document.getElementById("myCanvas");myCanvas.getContext("2d").clearRect(0, 0, myCanvas.width, myCanvas.height);}</script>""" HTML(html+script)

10：輸出權重：

def norm_stat(d):"""The statistics you want to see.We compute the L2 norm here but you can change it to anything you like."""return mx.nd.norm(d)/np.sqrt(d.size) mon = mx.mon.Monitor(100, # Print every 100 batchesnorm_stat, # The statistics function defined abovepattern='.*weight', # A regular expression. Only arrays with name matching this pattern will be included.sort=True) # Sort output by name model = mx.model.FeedForward(ctx = mx.gpu(0), symbol = mlp, num_epoch = 1,learning_rate = 0.1, momentum = 0.9, wd = 0.00001) model.fit(X=train_iter, eval_data=test_iter, monitor=mon, # Set the monitor herebatch_end_callback = mx.callback.Speedometer(100, 100))

11：就像之前所說的，數據ilter是能夠自己寫loop來聚類的

但說實話，自己寫的loop如何調用gpu？作者的自己寫的例子，也沒有調用gpu，我實在是懷疑

epoch迭代次數，ilter是分的數據patch的個數

一般來說沒必要寫自己的loop，所以不怎么推薦使用

# ==================Binding===================== # The symbol we created is only a graph description. # To run it, we first need to allocate memory and create an executor by 'binding' it. # In order to bind a symbol, we need at least two pieces of information: context and input shapes. # Context specifies which device the executor runs on, e.g. cpu, GPU0, GPU1, etc. # Input shapes define the executor's input array dimensions. # MXNet then run automatic shape inference to determine the dimensions of intermediate and output arrays.# data iterators defines shapes of its output with provide_data and provide_label property. input_shapes = dict(train_iter.provide_data+train_iter.provide_label) print 'input_shapes', input_shapes # We use simple_bind to let MXNet allocate memory for us. # You can also allocate memory youself and use bind to pass it to MXNet. exe = mlp.simple_bind(ctx=mx.gpu(0), **input_shapes)# ===============Initialization================= # First we get handle to input arrays arg_arrays = dict(zip(mlp.list_arguments(), exe.arg_arrays)) data = arg_arrays[train_iter.provide_data[0][0]] label = arg_arrays[train_iter.provide_label[0][0]]# We initialize the weights with uniform distribution on (-0.01, 0.01). init = mx.init.Uniform(scale=0.01) for name, arr in arg_arrays.items():if name not in input_shapes:init(name, arr)# We also need to create an optimizer for updating weights opt = mx.optimizer.SGD(learning_rate=0.1,momentum=0.9,wd=0.00001,rescale_grad=1.0/train_iter.batch_size) updater = mx.optimizer.get_updater(opt)# Finally we need a metric to print out training progress metric = mx.metric.Accuracy()# Training loop begines for epoch in range(10):train_iter.reset()metric.reset()t = 0for batch in train_iter:# Copy data to executor input. Note the [:].data[:] = batch.data[0]label[:] = batch.label[0]# Forwardexe.forward(is_train=True)# You perform operations on exe.outputs here if you need to.# For example, you can stack a CRF on top of a neural network.# Backward exe.backward()# Updatefor i, pair in enumerate(zip(exe.arg_arrays, exe.grad_arrays)):weight, grad = pairupdater(i, grad, weight)metric.update(batch.label, exe.outputs)t += 1if t % 100 == 0:print 'epoch:', epoch, 'iter:', t, 'metric:', metric.get()

12：新的層

輸入的數據，輸出數據個數都要好好申明

# Define custom softmax operator class NumpySoftmax(mx.operator.NumpyOp):def __init__(self):# Call the parent class constructor. # Because NumpySoftmax is a loss layer, it doesn't need gradient input from layers above.super(NumpySoftmax, self).__init__(need_top_grad=False)def list_arguments(self):# Define the input to NumpySoftmax.return ['data', 'label']def list_outputs(self):# Define the output.return ['output']def infer_shape(self, in_shape):# Calculate the dimensions of the output (and missing inputs) from (some) input shapes.data_shape = in_shape[0] # shape of first argument 'data'label_shape = (in_shape[0][0],) # 'label' should be one dimensional and has batch_size instances.output_shape = in_shape[0] # 'output' dimension is the same as the input.return [data_shape, label_shape], [output_shape]def forward(self, in_data, out_data):x = in_data[0] # 'data'y = out_data[0] # 'output'# Compute softmaxy[:] = np.exp(x - x.max(axis=1).reshape((x.shape[0], 1)))y /= y.sum(axis=1).reshape((x.shape[0], 1))def backward(self, out_grad, in_data, out_data, in_grad):l = in_data[1] # 'label'l = l.reshape((l.size,)).astype(np.int) # cast to inty = out_data[0] # 'output'dx = in_grad[0] # gradient for 'data'# Compute gradientdx[:] = ydx[np.arange(l.shape[0]), l] -= 1.0numpy_softmax = NumpySoftmax()data = mx.symbol.Variable('data') fc1 = mx.symbol.FullyConnected(data = data, name='fc1', num_hidden=128) act1 = mx.symbol.Activation(data = fc1, name='relu1', act_type="relu") fc2 = mx.symbol.FullyConnected(data = act1, name = 'fc2', num_hidden = 64) act2 = mx.symbol.Activation(data = fc2, name='relu2', act_type="relu") fc3 = mx.symbol.FullyConnected(data = act2, name='fc3', num_hidden=10) # Use the new operator we just defined instead of the standard softmax operator. mlp = numpy_softmax(data=fc3, name = 'softmax')model = mx.model.FeedForward(ctx = mx.gpu(0), symbol = mlp, num_epoch = 2,learning_rate = 0.1, momentum = 0.9, wd = 0.00001) model.fit(X=train_iter, eval_data=test_iter,batch_end_callback = mx.callback.Speedometer(100, 100))

13：新層加新的迭代：

我創建在example/mytest文件夾下面

#!/usr/bin/env python2 # -*- coding: utf-8 -*- """ Created on Thu Mar 30 15:35:02 2017@author: root """ from __future__ import print_function import sys import os # code to automatically download dataset curr_path = os.path.dirname(os.path.abspath(os.path.expanduser(__file__))) sys.path = [os.path.join(curr_path, "../autoencoder")] + sys.path import mxnet as mx import numpy as np import data from scipy.spatial.distance import cdist from sklearn.cluster import KMeans import model from autoencoder import AutoEncoderModel from solver import Solver, Monitor import logging import time global YT import scipy.io as sio import matplotlib.pyplot as plt # ==================start setting My-layer===================== class NumpySoftmax(mx.operator.NumpyOp):def __init__(self):# Call the parent class constructor. # Because NumpySoftmax is a loss layer, it doesn't need gradient input from layers above.super(NumpySoftmax, self).__init__(need_top_grad=False)def list_arguments(self):# Define the input to NumpySoftmax.return ['data', 'label']def list_outputs(self):# Define the output.return ['output']def infer_shape(self, in_shape):# Calculate the dimensions of the output (and missing inputs) from (some) input shapes.data_shape = in_shape[0] # shape of first argument 'data'label_shape = (in_shape[0][0],) # 'label' should be one dimensional and has batch_size instances.output_shape = in_shape[0] # 'output' dimension is the same as the input.return [data_shape, label_shape], [output_shape]def forward(self, in_data, out_data):alpha=1.0z = in_data[0]q= out_data[0] # 'output'kmeans = KMeans(n_clusters=10, random_state=170).fit(z)mu=kmeans.cluster_centers_ # Compute softmaxmask = 1.0/(1.0+cdist(z, mu)**2/alpha)q[:] = mask**((alpha+1.0)/2.0)q[:] = (q.T/q.sum(axis=1)).Tdef backward(self, out_grad, in_data, out_data, in_grad):alpha=1.0x = in_data[0] # 'label'y = out_data[0] # 'output'dx = in_grad[0] # gradient for 'data'kmeans = KMeans(n_clusters=10, random_state=170).fit(x)mu=kmeans.cluster_centers_ mask = 1.0/(1.0+cdist(x, mu)**2/alpha)p = mask**((alpha+1.0)/2.0)mask*= (alpha+1.0)/alpha*(p-y)dx[:] = (x.T*mask.sum(axis=1)).T - mask.dot(mu) #======================end setting========================== # ==================start of the process of data===================== X, Y = data.get_mnist() X_train = X[:60000] X_test = X[60000:] Y_train = Y[:60000] Y_test = Y[60000:] numpy_softmax = NumpySoftmax() batch_size = 100 #the office code to create iter train_iter = mx.io.NDArrayIter(X_train, Y_train, batch_size=batch_size) test_iter = mx.io.NDArrayIter(X_test, Y_test, batch_size=batch_size) input_shapes = dict(train_iter.provide_data+train_iter.provide_label) # ==================end of the process===================== # ==================start of setting the net===================== data = mx.symbol.Variable('data') fc1 = mx.symbol.FullyConnected(data = data, name='fc1', num_hidden=128) act1 = mx.symbol.Activation(data = fc1, name='relu1', act_type="relu") fc2 = mx.symbol.FullyConnected(data = act1, name = 'fc2', num_hidden = 64) act2 = mx.symbol.Activation(data = fc2, name='relu2', act_type="relu") fc3 = mx.symbol.FullyConnected(data = act2, name='fc3', num_hidden=10) mlp = numpy_softmax(data=fc3, name = 'softmax') mx.viz.plot_network(mlp).view() # ==================start of setting the net===================== exe = mlp.simple_bind(ctx=mx.gpu(0), **input_shapes) # ===============Initialization================= # First we get handle to input arrays arg_arrays = dict(zip(mlp.list_arguments(), exe.arg_arrays)) data = arg_arrays[train_iter.provide_data[0][0]] label = arg_arrays[train_iter.provide_label[0][0]]# We initialize the weights with uniform distribution on (-0.01, 0.01). init = mx.init.Uniform(scale=0.01) for name, arr in arg_arrays.items():if name not in input_shapes:init(name, arr)# We also need to create an optimizer for updating weights opt = mx.optimizer.SGD(learning_rate=0.1,momentum=0.9,wd=0.00001,rescale_grad=1.0/train_iter.batch_size) updater = mx.optimizer.get_updater(opt)# Finally we need a metric to print out training progress metric = mx.metric.Accuracy()# Training loop begines for epoch in range(10):train_iter.reset()metric.reset()t = 0for batch in train_iter:# Copy data to executor input. Note the [:].data[:] = batch.data[0]label[:] = batch.label[0]# Forwardexe.forward(is_train=True)# You perform operations on exe.outputs here if you need to.# For example, you can stack a CRF on top of a neural network.# Backward exe.backward()# Updatefor i, pair in enumerate(zip(exe.arg_arrays, exe.grad_arrays)):weight, grad = pairupdater(i, grad, weight)metric.update(batch.label, exe.outputs)t += 1if t % 100 == 0:print('epoch:', epoch, 'iter:', t, 'metric:', metric.get())

?

轉載于:https://www.cnblogs.com/kangronghu/p/mxnet.html

總結

以上是生活随笔為你收集整理的mxnet教程的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。