# What is the meaning of max of a variable?

For e.g. we create a net named ‘net’. y = net(x). what is meaning of y.max(1)? (especially a,b = y.max(1), what does it mean?)I saw the range of max is (-2,1). what does that mean.

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https://www.tutorialspoint.com/python/list_max.htm

I think you can relate with this.

Let’s check the docs http://pytorch.org/docs/0.3.1/tensors.html#torch.Tensor.max

`y.max(1)` takes the max over dimension 1 and returns two values. an example would help.

Supposing we have a tensor `y` of shape (3, 4) containing

`````` 0.6857  0.1098  0.4687  0.7822
0.4170  0.2476  0.1339  0.5563
0.9425  0.8433  0.1335  0.3169
``````

`y.max(1)` returns two tensors…

``````# 1. the max value in each row of y
0.7822
0.5563
0.9425
# 2. the column index at which the max value is found.
3
3
0
``````
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Why does y.max(1), give the max element in each row? (dimensions in Numpy are 0 indexed- so 0 for row, 1 for coloumn) Why is it different in PyTorch?

`max(1)` will return the maximal value (and index in PyTorch) in this particular dimension.
Both, numpy and PyTorch return the same values (PyTorch additionally with the indices):

``````x = np.random.randn(10, 10)
print(x.max(1))
print(torch.from_numpy(x).max(1))
``````
1 Like

Thank you for the examples!