标签：ict flat 方差 make val 构建 elf 不能 orm
Data = namedtuple(‘Data‘, [‘x‘, ‘y‘, ‘adjacency‘, ‘train_mask‘, ‘val_mask‘, ‘test_mask‘])
Cora数据，包括数据下载，处理，加载等功能。当数据的缓存文件存在时，将使用缓存文件，否则将下载、进行处理，并缓存到磁盘
class CoraData(object):
download_url = "https://github.com/kimiyoung/planetoid/raw/master/data"
filenames = ["ind.cora.{}".format(name) for name in
[‘x‘, ‘tx‘, ‘allx‘, ‘y‘, ‘ty‘, ‘ally‘, ‘graph‘, ‘test.index‘]]
def __init__(self, data_root="cora", rebuild=False):
self.data_root = data_root
save_file = osp.join(self.data_root, "processed_cora.pkl") #Python join() 方法用于将序列中的元素以指定的字符连接生成一个新的字符串。
if osp.exists(save_file) and not rebuild:
print("Using Cached file: {}".format(save_file))
self._data = pickle.load(open(save_file, "rb"))
else:
self.maybe_download()
self._data = self.process_data()
with open(save_file, "wb") as f:
pickle.dump(self.data, f)
print("Cached file: {}".format(save_file)) #Cached file缓存文件
def data(self):
"""返回Data数据对象，包括x, y, adjacency, train_mask, val_mask, test_mask"""
return self._data
def process_data(self):
"""
处理数据，得到节点特征和标签，邻接矩阵，训练集、验证集以及测试集
引用自：https://github.com/rusty1s/pytorch_geometric
"""
print("Process data ...")
_, tx, allx, y, ty, ally, graph, test_index = [self.read_data(
osp.join(self.data_root, "raw", name)) for name in self.filenames]
train_index = np.arange(y.shape[0])
val_index = np.arange(y.shape[0], y.shape[0] + 500)
sorted_test_index = sorted(test_index)
x = np.concatenate((allx, tx), axis=0)
y = np.concatenate((ally, ty), axis=0).argmax(axis=1)
x[test_index] = x[sorted_test_index]
y[test_index] = y[sorted_test_index]
num_nodes = x.shape[0]
train_mask = np.zeros(num_nodes, dtype=np.bool)
val_mask = np.zeros(num_nodes, dtype=np.bool)
test_mask = np.zeros(num_nodes, dtype=np.bool)
train_mask[train_index] = True
val_mask[val_index] = True
test_mask[test_index] = True
adjacency = self.build_adjacency(graph)
print("Node‘s feature shape: ", x.shape)
print("Node‘s label shape: ", y.shape)
print("Adjacency‘s shape: ", adjacency.shape)
print("Number of training nodes: ", train_mask.sum())
print("Number of validation nodes: ", val_mask.sum())
print("Number of test nodes: ", test_mask.sum())
return Data(x=x, y=y, adjacency=adjacency,
train_mask=train_mask, val_mask=val_mask, test_mask=test_mask)
def maybe_download(self):
save_path = os.path.join(self.data_root, "raw")
for name in self.filenames:
if not osp.exists(osp.join(save_path, name)):
self.download_data(
"{}/{}".format(self.download_url, name), save_path)
@staticmethod
def build_adjacency(adj_dict):
"""根据邻接表创建邻接矩阵"""
edge_index = []
num_nodes = len(adj_dict)
for src, dst in adj_dict.items():
edge_index.extend([src, v] for v in dst)
edge_index.extend([v, src] for v in dst)
# 去除重复的边
edge_index = list(k for k, _ in itertools.groupby(sorted(edge_index)))
edge_index = np.asarray(edge_index)
adjacency = sp.coo_matrix((np.ones(len(edge_index)),
(edge_index[:, 0], edge_index[:, 1])),
shape=(num_nodes, num_nodes), dtype="float32")
return adjacency
@staticmethod
def read_data(path):
"""使用不同的方式读取原始数据以进一步处理"""
name = osp.basename(path)
if name == "ind.cora.test.index":
out = np.genfromtxt(path, dtype="int64")
return out
else:
out = pickle.load(open(path, "rb"), encoding="latin1")
out = out.toarray() if hasattr(out, "toarray") else out
return out
@staticmethod
def download_data(url, save_path):
"""数据下载工具，当原始数据不存在时将会进行下载"""
if not os.path.exists(save_path):
os.makedirs(save_path)
data = urllib.request.urlopen(url)
filename = os.path.split(url)[-1]
with open(os.path.join(save_path, filename), ‘wb‘) as f:
f.write(data.read())
return True
@staticmethod
def normalization(adjacency):
"""计算 L=D^-0.5 * (A+I) * D^-0.5"""
adjacency += sp.eye(adjacency.shape[0]) # 增加自连接
degree = np.array(adjacency.sum(1))
d_hat = sp.diags(np.power(degree, -0.5).flatten())
return d_hat.dot(adjacency).dot(d_hat).tocoo()
# # 基于Cora数据集的GCN节点分类
# In[1]:
import itertools #循环器每次返回的对象将赋予给i，直到循环结束
import os
import os.path as osp
import pickle #可以将对象以文件的形式存放在磁盘上。
import urllib #urllib是python内置的http请求库
from collections import namedtuple #具名元组
import numpy as np
import scipy.sparse as sp
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.nn.init as init
import torch.optim as optim
import matplotlib.pyplot as plt
# ## 数据准备
# In[2]:
Data = namedtuple(‘Data‘, [‘x‘, ‘y‘, ‘adjacency‘,
‘train_mask‘, ‘val_mask‘, ‘test_mask‘])
class CoraData(object):
download_url = "https://github.com/kimiyoung/planetoid/raw/master/data"
filenames = ["ind.cora.{}".format(name) for name in
[‘x‘, ‘tx‘, ‘allx‘, ‘y‘, ‘ty‘, ‘ally‘, ‘graph‘, ‘test.index‘]]
def __init__(self, data_root="cora", rebuild=False):
"""Cora数据，包括数据下载，处理，加载等功能
当数据的缓存文件存在时，将使用缓存文件，否则将下载、进行处理，并缓存到磁盘
处理之后的数据可以通过属性 .data 获得，它将返回一个数据对象，包括如下几部分：
* x: 节点的特征，维度为 2708 * 1433，类型为 np.ndarray
* y: 节点的标签，总共包括7个类别，类型为 np.ndarray
* adjacency: 邻接矩阵，维度为 2708 * 2708，类型为 scipy.sparse.coo.coo_matrix
* train_mask: 训练集掩码向量，维度为 2708，当节点属于训练集时，相应位置为True，否则False
* val_mask: 验证集掩码向量，维度为 2708，当节点属于验证集时，相应位置为True，否则False
* test_mask: 测试集掩码向量，维度为 2708，当节点属于测试集时，相应位置为True，否则False
Args:
-------
data_root: string, optional
存放数据的目录，原始数据路径: {data_root}/raw
缓存数据路径: {data_root}/processed_cora.pkl
rebuild: boolean, optional
是否需要重新构建数据集，当设为True时，如果存在缓存数据也会重建数据
"""
self.data_root = data_root
save_file = osp.join(self.data_root, "processed_cora.pkl") #Python join() 方法用于将序列中的元素以指定的字符连接生成一个新的字符串。
if osp.exists(save_file) and not rebuild:
print("Using Cached file: {}".format(save_file))
self._data = pickle.load(open(save_file, "rb"))
else:
self.maybe_download()
self._data = self.process_data()
with open(save_file, "wb") as f:
pickle.dump(self.data, f)
print("Cached file: {}".format(save_file))
@property
def data(self):
"""返回Data数据对象，包括x, y, adjacency, train_mask, val_mask, test_mask"""
return self._data
def process_data(self):
"""
处理数据，得到节点特征和标签，邻接矩阵，训练集、验证集以及测试集
引用自：https://github.com/rusty1s/pytorch_geometric
"""
print("Process data ...")
_, tx, allx, y, ty, ally, graph, test_index = [self.read_data(
osp.join(self.data_root, "raw", name)) for name in self.filenames]
train_index = np.arange(y.shape[0])
val_index = np.arange(y.shape[0], y.shape[0] + 500)
sorted_test_index = sorted(test_index)
x = np.concatenate((allx, tx), axis=0)
y = np.concatenate((ally, ty), axis=0).argmax(axis=1)
x[test_index] = x[sorted_test_index]
y[test_index] = y[sorted_test_index]
num_nodes = x.shape[0]
train_mask = np.zeros(num_nodes, dtype=np.bool)
val_mask = np.zeros(num_nodes, dtype=np.bool)
test_mask = np.zeros(num_nodes, dtype=np.bool)
train_mask[train_index] = True
val_mask[val_index] = True
test_mask[test_index] = True
adjacency = self.build_adjacency(graph)
print("Node‘s feature shape: ", x.shape)
print("Node‘s label shape: ", y.shape)
print("Adjacency‘s shape: ", adjacency.shape)
print("Number of training nodes: ", train_mask.sum())
print("Number of validation nodes: ", val_mask.sum())
print("Number of test nodes: ", test_mask.sum())
return Data(x=x, y=y, adjacency=adjacency,
train_mask=train_mask, val_mask=val_mask, test_mask=test_mask)
def maybe_download(self):
save_path = os.path.join(self.data_root, "raw")
for name in self.filenames:
if not osp.exists(osp.join(save_path, name)):
self.download_data(
"{}/{}".format(self.download_url, name), save_path)
@staticmethod
def build_adjacency(adj_dict):
"""根据邻接表创建邻接矩阵"""
edge_index = []
num_nodes = len(adj_dict)
for src, dst in adj_dict.items():
edge_index.extend([src, v] for v in dst)
edge_index.extend([v, src] for v in dst)
# 去除重复的边
edge_index = list(k for k, _ in itertools.groupby(sorted(edge_index)))
edge_index = np.asarray(edge_index)
adjacency = sp.coo_matrix((np.ones(len(edge_index)),
(edge_index[:, 0], edge_index[:, 1])),
shape=(num_nodes, num_nodes), dtype="float32")
return adjacency
@staticmethod
def read_data(path):
"""使用不同的方式读取原始数据以进一步处理"""
name = osp.basename(path)
if name == "ind.cora.test.index":
out = np.genfromtxt(path, dtype="int64")
return out
else:
out = pickle.load(open(path, "rb"), encoding="latin1")
out = out.toarray() if hasattr(out, "toarray") else out
return out
@staticmethod
def download_data(url, save_path):
"""数据下载工具，当原始数据不存在时将会进行下载"""
if not os.path.exists(save_path):
os.makedirs(save_path)
data = urllib.request.urlopen(url)
filename = os.path.split(url)[-1]
with open(os.path.join(save_path, filename), ‘wb‘) as f:
f.write(data.read())
return True
@staticmethod
def normalization(adjacency):
"""计算 L=D^-0.5 * (A+I) * D^-0.5"""
adjacency += sp.eye(adjacency.shape[0]) # 增加自连接
degree = np.array(adjacency.sum(1))
d_hat = sp.diags(np.power(degree, -0.5).flatten())
return d_hat.dot(adjacency).dot(d_hat).tocoo()
# ## 图卷积层定义
# In[3]:
class GraphConvolution(nn.Module):
def __init__(self, input_dim, output_dim, use_bias=True):
"""图卷积：L*X*\theta
Args:
----------
input_dim: int
节点输入特征的维度
output_dim: int
输出特征维度
use_bias : bool, optional
是否使用偏置
"""
super(GraphConvolution, self).__init__()
self.input_dim = input_dim
self.output_dim = output_dim
self.use_bias = use_bias
self.weight = nn.Parameter(torch.Tensor(input_dim, output_dim))
if self.use_bias:
self.bias = nn.Parameter(torch.Tensor(output_dim))
else:
self.register_parameter(‘bias‘, None)
self.reset_parameters()
def reset_parameters(self):
init.kaiming_uniform_(self.weight)
if self.use_bias:
init.zeros_(self.bias)
def forward(self, adjacency, input_feature):
"""邻接矩阵是稀疏矩阵，因此在计算时使用稀疏矩阵乘法
Args:
-------
adjacency: torch.sparse.FloatTensor
邻接矩阵
input_feature: torch.Tensor
输入特征
"""
support = torch.mm(input_feature, self.weight)
output = torch.sparse.mm(adjacency, support)
if self.use_bias:
output += self.bias
return output
def __repr__(self):
return self.__class__.__name__ + ‘ (‘ + str(self.in_features) + ‘ -> ‘ + str(self.out_features) + ‘)‘
# ## 模型定义
# In[4]:
class GcnNet(nn.Module):
"""
定义一个包含两层GraphConvolution的模型
"""
def __init__(self, input_dim=1433):
super(GcnNet, self).__init__()
self.gcn1 = GraphConvolution(input_dim, 16)
self.gcn2 = GraphConvolution(16, 7)
def forward(self, adjacency, feature):
h = F.relu(self.gcn1(adjacency, feature))
logits = self.gcn2(adjacency, h)
return logits
# ## 模型训练
# In[5]:
# 超参数定义
learning_rate = 0.1 #学习率或步长因子
weight_decay = 5e-4 #权重衰减（L2惩罚）
epochs = 200
# In[6]:
# 模型定义：Model, Loss, Optimizer
device = "cuda" if torch.cuda.is_available() else "cpu"
print(device)
model = GcnNet().to(device)
criterion = nn.CrossEntropyLoss().to(device) #交叉熵的值越小，两个概率分布就越接近（实际输出（概率）与期望输出（概率））
optimizer = optim.Adam(model.parameters(), lr=learning_rate, weight_decay=weight_decay)
# In[7]:
# 加载数据，并转换为torch.Tensor
dataset = CoraData().data
x = dataset.x / dataset.x.sum(1, keepdims=True) # 归一化数据，使得每一行和为1
tensor_x = torch.from_numpy(x).to(device)
tensor_y = torch.from_numpy(dataset.y).to(device)
tensor_train_mask = torch.from_numpy(dataset.train_mask).to(device)
tensor_val_mask = torch.from_numpy(dataset.val_mask).to(device)
tensor_test_mask = torch.from_numpy(dataset.test_mask).to(device)
normalize_adjacency = CoraData.normalization(dataset.adjacency) # 规范化邻接矩阵
"""计算 L=D^-0.5 * (A+I) * D^-0.5"""
indices = torch.from_numpy(np.asarray([normalize_adjacency.row,
normalize_adjacency.col]).astype(‘int64‘)).long()
#索引
values = torch.from_numpy(normalize_adjacency.data.astype(np.float32))
#数值
tensor_adjacency = torch.sparse.FloatTensor(indices, values,
(2708, 2708)).to(device)
#传到GPU
# In[8]:
# 训练主体函数
def train():
loss_history = []
val_acc_history = []
model.train() #保证BN层用每一批数据的均值和方差
train_y = tensor_y[tensor_train_mask] #取出训练集
for epoch in range(epochs): #1到200
logits = model(tensor_adjacency, tensor_x) # 前向传播
train_mask_logits = logits[tensor_train_mask] # 只选择训练节点进行监督
loss = criterion(train_mask_logits, train_y) # 计算损失值
optimizer.zero_grad() #是把梯度置零，也就是把loss关于weight的导数变成0.
loss.backward() # 反向传播计算参数的梯度
optimizer.step() # 使用优化方法进行梯度更新
train_acc, _, _ = test(tensor_train_mask) # 计算当前模型训练集上的准确率
val_acc, _, _ = test(tensor_val_mask) # 计算当前模型在验证集上的准确率
# 记录训练过程中损失值和准确率的变化，用于画图
loss_history.append(loss.item())
val_acc_history.append(val_acc.item())
print("Epoch {:03d}: Loss {:.4f}, TrainAcc {:.4}, ValAcc {:.4f}".format(
epoch, loss.item(), train_acc.item(), val_acc.item()))
return loss_history, val_acc_history
# In[9]:
# 测试函数
def test(mask):
model.eval() #不启用 BatchNormalization 和 Dropout
with torch.no_grad(): #不能进行梯度计算的上下文管理器。
logits = model(tensor_adjacency, tensor_x)
test_mask_logits = logits[mask]
predict_y = test_mask_logits.max(1)[1]
accuarcy = torch.eq(predict_y, tensor_y[mask]).float().mean()
return accuarcy, test_mask_logits.cpu().numpy(), tensor_y[mask].cpu().numpy()
# In[13]:
def plot_loss_with_acc(loss_history, val_acc_history):
fig = plt.figure()
ax1 = fig.add_subplot(111)
ax1.plot(range(len(loss_history)), loss_history,
c=np.array([255, 71, 90]) / 255.)
plt.ylabel(‘Loss‘)
ax2 = fig.add_subplot(111, sharex=ax1, frameon=False)
ax2.plot(range(len(val_acc_history)), val_acc_history,
c=np.array([79, 179, 255]) / 255.)
ax2.yaxis.tick_right()
ax2.yaxis.set_label_position("right")
plt.ylabel(‘ValAcc‘)
plt.xlabel(‘Epoch‘)
plt.title(‘Training Loss & Validation Accuracy‘)
plt.show()
# In[ ]:
loss, val_acc = train()
test_acc, test_logits, test_label = test(tensor_test_mask)
print("Test accuarcy: ", test_acc.item())
# In[14]:
plot_loss_with_acc(loss, val_acc)
# In[ ]:
标签：ict flat 方差 make val 构建 elf 不能 orm
原文地址：https://www.cnblogs.com/aluckystone/p/14163591.html
