th> a = torch.ones(4,3,2)
th> b = nn.SpatialAveragePooling(2,2)(a)
th> b

(1,.,.) =
1
1

(2,.,.) =
1
1

(3,.,.) =
1
1

(4,.,.) =
1
1

th> a = torch.ones(3,2,2)
th> b = nn.SpatialAveragePooling(2,2)(a)
th> b

(1,.,.) =
1

(2,.,.) =
1

(3,.,.) =
1