Pytorch view -1 meaning

View(-1) in pytorch

import torch

x = torch.arange(6)

print(x.view(3, -1))      # inferred size will be 2 as 6 / 3 = 2
# tensor([[ 0.,  1.],
#         [ 2.,  3.],
#         [ 4.,  5.]])

print(x.view(-1, 6))      # inferred size will be 1 as 6 / 6 = 1
# tensor([[ 0.,  1.,  2.,  3.,  4.,  5.]])

print(x.view(1, -1, 2))   # inferred size will be 3 as 6 / (1 * 2) = 3
# tensor([[[ 0.,  1.],
#          [ 2.,  3.],
#          [ 4.,  5.]]])

# print(x.view(-1, 5))    # throw error as there's no int N so that 5 * N = 6
# RuntimeError: invalid argument 2: size '[-1 x 5]' is invalid for input with 6 elements

print(x.view(-1, -1, 3))  # throw error as only one dimension can be inferred
# RuntimeError: invalid argument 1: only one dimension can be inferred

Source: stackoverflow.com

Pytorch view -1 meaning

If there is any situation that you don't know how many rows you want but are sure of the number of columns, then you can specify this with a -1. (Note that you can extend this to tensors with more dimensions. Only one of the axis value can be -1). This is a way of telling the library: "give me a tensor that has these many columns and you compute the appropriate number of rows that is necessary to make this happen".

Similar codes

53 votes107 views3 answers
How to find length of list python
Python
1 vote100 views2 answers
Np matrix drop zero column
Python
0 vote97 views2 answers
Diagonal difference hackerrank solution in python
Python
0 vote134 views1 answer
Python a, b =
Python
4 votes125 views1 answer
Django pandas queryset
Python Django
0 vote99 views1 answer
Unhexing floats
Python
0 vote101 views1 answer
Get version of cuda in pytorch
Python
22 votes100 views6 answers
How to check django version
Python
5 votes102 views6 answers
How to find unique values in numpy array
Python
1 vote107 views1 answer
Fill na with mode and mean python
Python