How to define train_mask, val_mask, test_mask, ... in my own dataset?

I’ve tried to build a GCN to train my own data which are nodes with only one feature on each node.
However I encountered a problem, how can I define attributes “train_mask”, “test_mask”, “val_mask” like what they have in the built-in dataset?

My code:


#########################################################
### Headers.
#########################################################

import sys
import re
import random
import torch
import torch.nn.functional as F
from fnmatch import fnmatch 
from torch_geometric.data import Data
from torch_geometric.nn import GCNConv

#########################################################
### Variables Declaration.
#########################################################

graphFileIn = "graph_001.txt" #sys.argv[1]
mapFileIn = "map_001.txt" #sys.argv[2]
run_name = ""
lr = 1e-3
epochs = 100
weight_decay = 5e-4
#########################################################
### Read in netlist graph.
#########################################################

def read_netlist_graph(graphFileIn, mapFileIn):
    edge_v1 = []
    edge_v2 = []
    node_number = 0

    for line in open(graphFileIn, 'r'):
        data = line.split()
        node1 = int(data[0])
        node2 = int(data[1])
        weight = data[2]
        edge_v1.append( node1 )
        edge_v2.append( node2 )

    print("v1:", len(edge_v1), "v2:",len(edge_v2))

    for line in open(mapFileIn, 'r'):
        node_number += 1
    print("Node no.",node_number)
    print("Edge1 len", len(edge_v1), "Edge2_len",len(edge_v2))
    return edge_v1, edge_v2, node_number

#########################################################
### Build netlist graph in PyTorch form.
#########################################################

def build_netlist_graph(edge_v1, edge_v2, node_number):
    edge_index = torch.tensor([edge_v1,
                               edge_v2], 
                              dtype = torch.long)

    print("edge_idx:", edge_index)

    i = 1
    feature_v = []

    for i in range(node_number):
        feature_v.append(random.sample(range(0, 2),1))

    print("Feature length:", len(feature_v))

    x = torch.tensor(feature_v, 
                     dtype = torch.float)
    
    data = Data(x = x, 
                edge_index = edge_index,
                #edge_index = edge_index.t().contiguous(),
                num_classes = 2,
    )

    print("Data keys:",data.keys)
    print("data['x']:", data['x'])
    print("num_edges:",data.num_edges)
    print("num_nodes:",data.num_nodes)
    print("directed:", data.is_directed())
    print("data.num_node_features:",data.num_node_features)
    return data

#########################################################
### Learning on Graphs
#########################################################

class Net(torch.nn.Module):

    ### Constructor
    def __init__(self):

        ### super is used to inherit from the torch.nn.module.
        super(Net, self).__init__()

        #class GCNConv(in_channels, 
        #              out_channels, improved=False, 
        #              cached=False, bias=True, **kwargs)

        self.conv1 = GCNConv(data.num_node_features, 16)
        self.conv2 = GCNConv(16, data.num_classes)


    def forward(self, data):
        x, edge_index = data.x, data.edge_index

        print("x:",x.size(), "e_idx", edge_index.size())
 
        print("x_shape:", x.shape)
        x = self.conv1(x, edge_index)
        x = F.relu(x)
        x = F.dropout(x, training=self.training)
        x = self.conv2(x, edge_index)

        return F.log_softmax(x, dim=1)

def graph_learning(data):
    
    device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
    model = Net().to(device)
    data = data #dataset[0].to(device)
    optimizer = torch.optim.Adam(model.parameters(), 
                                 lr = lr, 
                                 weight_decay = weight_decay)

    model.train()

    for epoch in range(epochs):
        optimizer.zero_grad()
        out = model(data)
        loss = F.nll_loss(out[data.train_mask], 
                          data.y[data.train_mask])
        loss.backward()
        optimizer.step()

        model.eval()
        _, pred = model(data).max(dim = 1)
        correct = float (
            pred[data.test_mask].eq(data.y[data.test_mask]).sum().item())
        acc = correct / data.test_mask.sum().item()
        print('Accuracy: {:.4f}'.format(acc))

#########################################################
### Main function.
#########################################################

if __name__ == '__main__':

    (edge_v1, 
    edge_v2, 
    node_number) = read_netlist_graph(graphFileIn, mapFileIn)

    data = build_netlist_graph(edge_v1, edge_v2, node_number)

    graph_learning(data)

Error messages:

v1: 127378 v2: 127378
Node no. 11354
Edge1 len 127378 Edge2_len 127378
edge_idx: tensor([[    0,     0,     1,  ..., 11353,  4724,  2357],
        [    1,     4,     4,  ...,  2342,  2342,   512]])
Feature length: 11354
Data keys: ['x', 'edge_index', 'num_classes']
data['x']: tensor([[0.],
        [1.],
        [1.],
        ...,
        [1.],
        [1.],
        [0.]])
num_edges: 127378
num_nodes: 11354
directed: True
data.num_node_features: 1
x: torch.Size([11354, 1]) e_idx torch.Size([2, 127378])
x_shape: torch.Size([11354, 1])
Traceback (most recent call last):
  File "gcn_pytorch.py", line 164, in <module>
    graph_learning(data)
  File "gcn_pytorch.py", line 140, in graph_learning
    loss = F.nll_loss(out[data.train_mask], 
AttributeError: 'Data' object has no attribute 'train_mask'

Well so the Data object that you create doesn’t inherently have a train_mask, val_mask, or test_mask but if you want, you can define these as tensors and add them as attributes to your Data object. In other words, the Data object is extendable (see https://pytorch-geometric.readthedocs.io/en/latest/modules/data.html).

data = Data(x=x, edge_index=edge_index)
data.train_idx = torch.tensor([…], dtype=torch.long)
data.test_mask = torch.tensor([…], dtype=torch.uint8)

Another way to do this would be to create a separate Data object for your training, testing and validation data sets. This is perhaps preferable because there is less likelihood of data peeking if the data is stored in completely separate objects.

1 Like

Thanks. So the train_mask and test_mask looks like this? (if I have no validation set) train_mask = [ [index1, feature1], [index2, feature2], … , [indexN, featureN] ] and test_mask = [ [indexN+1, featureN+1], [indexN+2, featureN+2], … , [indexM, featureM] ] ?

To be honest, I’ve never used the torch_geometric Data class so I don’t know for sure. To get a subset of indices from a tensor T, you’d do the following:

T = torch.randn(10,5,5) # create some dummy data for example
idx = torch.tensor([1,2,4,7],dtype=torch.uint8) # make tensor of desired indices
T.shape # returns (10,5,5)
T[idx].shape # returns (4,5,5)

I’d guess that the way the Data class is defined, grabbing a subset of the indices in a Data object will slice each of the attributes in Data in the way defined above, though I can’t be 100% sure and I’m too lazy to download the packages to check.

You should try using the format above, where idx is a 1D tensor with the indices of your desired train_mask and test_mask.

So by saying “create a separate Data object for your training, testing and validation data sets.”
Do you mean that I could convert my current data construction:

    data = Data(x = x, 
                edge_index = edge_index,
                num_classes = 2,
    )

Into something like:

    train_mask = Data(x = x[0:300], 
                edge_index = edge_index,
                num_classes = 2,
    )
    test_mask = Data(x = x[300:], 
                edge_index = edge_index,
                num_classes = 2,
    )


Hi experts,
I solved this problem, thank you.

1 Like

Great stuff Beherit =) how did you solve it? I’m also defining my own dataset for pytorch geometric, and stumbled upon the same issue. Any chance you could share the working code? Thanks alot =)

1 Like

Compiling the information in this thread: to create a mask for a custom training set you have to A). define the mask B). extend the Data attribute C). collate the Data objects into a Dataset.

data_point = torch_geometric.data.Data(x=x, edge_index=edge_index, y=y)
data_point.train_mask = torch.Tensor([...], dtype=torch.bool)  // [...] is of length y
training_data.append(data_point)  // repeat lines 1-3
loader = DataLoader(training_data, batch_size=32) 

Hope this helps everyone!

2 Likes

@ArthurXwandY, it is not clear how to make the split, after adding the train_mask (training_data is not defined).
Can you elaborate on that please?
Thanks

I figured it out.
training_data is a list of Data objects, where a Data object is formed by one example from the training set (repeating this process for all the training set).
The DataLoader helps you to loop over chunks of Data objects (the chunk size is batch_size)