Flux
istraining
(
)
=
false
ChainRulesCore
.
rrule
(
::
typeof
(
istraining
)
)
=
true
,
_
->
(
NoTangent
(
)
,
)
_isactive
(
m
)
=
isnothing
(
m
.
active
)
?
istraining
(
)
:
m
.
active
_dropout_shape
(
s
,
::
Colon
)
=
size
(
s
)
_dropout_shape
(
s
,
dims
)
=
tuple
(
(
i
∉
dims
?
1
:
si
for
(
i
,
si
)
∈
enumerate
(
size
(
s
)
)
)
...
)
_dropout_kernel
(
y
::
T
,
p
,
q
)
where
{
T
}
=
y
>
p
?
T
(
1
/
q
)
:
T
(
0
)
"""
dropout([rng = rng_from_array(x)], x, p; dims=:, active=true)
The dropout function. If `active` is `true`,
for each input, either sets that input to `0` (with probability
`p`) or scales it by `1 / (1 - p)`. `dims` specifies the unbroadcasted dimensions,
e.g. `dims=1` applies dropout along columns and `dims=2` along rows.
If `active` is `false`, it just returns the input `x`.
Specify `rng` for custom RNGs instead of the default RNG.
Note that custom RNGs are only supported on the CPU.
Warning: when using this function, you have to manually manage the activation
state. Usually in fact, dropout is used while training
but is deactivated in the inference phase. This can be
automatically managed using the [`Dropout`](@ref) layer instead of the
`dropout` function.
The [`Dropout`](@ref) layer is what you should use in most scenarios.
"""
function
dropout
(
rng
,
x
,
p
;
dims
=
:
,
active
::
Bool
=
true
)
active
||
return
x
y
=
dropout_mask
(
rng
,
x
,
p
,
dims
=
dims
)
return
x
.*
y
end
dropout
(
x
,
p
;
kwargs
...
)
=
dropout
(
rng_from_array
(
x
)
,
x
,
p
;
kwargs
...
)
dropout_mask
(
rng
::
CUDA
.
RNG
,
x
::
CuArray
,
p
;
kwargs
...
)
=
_dropout_mask
(
rng
,
x
,
p
;
kwargs
...
)
dropout_mask
(
rng
,
x
::
CuArray
,
p
;
kwargs
...
)
=
throw
(
ArgumentError
(
"
x isa CuArray, but rng isa
$
(
typeof
(
rng
)
)
. dropout_mask only support CUDA.RNG for CuArrays.
"
)
)
dropout_mask
(
rng
,
x
,
p
;
kwargs
...
)
=
_dropout_mask
(
rng
,
x
,
p
;
kwargs
...
)
function
_dropout_mask
(
rng
,
x
,
p
;
dims
=
:
)
realfptype
=
float
(
real
(
eltype
(
x
)
)
)
y
=
rand!
(
rng
,
similar
(
x
,
realfptype
,
_dropout_shape
(
x
,
dims
)
)
)
y
.=
_dropout_kernel
.
(
y
,
p
,
1
-
p
)
return
y
endTODO move this to NNlib
ChainRulesCore
.
@
non_differentiable
dropout_mask
(
::
Any
,
::
Any
,
::
Any
)
"""
Dropout(p; dims=:, rng = default_rng_value())
Dropout layer.
While training, for each input, this layer either sets that input to `0` (with probability
`p`) or scales it by `1 / (1 - p)`. To apply dropout along certain dimension(s), specify the
`dims` keyword. e.g. `Dropout(p; dims = 3)` will randomly zero out entire channels on WHCN input
(also called 2D dropout). This is used as a regularisation, i.e. it reduces overfitting during
training.
In the forward pass, this layer applies the [`Flux.dropout`](@ref) function. See that for more
details.
Specify `rng` to use a custom RNG instead of the default.
Custom RNGs are only supported on the CPU.
Does nothing to the input once [`Flux.testmode!`](@ref) is `true`.
# Examples
```jldoctest
julia> m = Chain(Dense(1 => 1), Dropout(1));
julia> Flux.trainmode!(m);
julia> y = m([1]);
julia> y == [0]
true
julia> m = Chain(Dense(1000 => 1000), Dropout(0.5));
julia> Flux.trainmode!(m);
julia> y = m(ones(1000));
julia> isapprox(count(==(0), y) / length(y), 0.5, atol=0.1)
true
```
"""
mutable
struct
Dropout
{
F
,
D
,
R
<:
AbstractRNG
}
p
::
F
dims
::
D
active
::
Union
{
Bool
,
Nothing
}
rng
::
R
end
Dropout
(
p
,
dims
,
active
)
=
Dropout
(
p
,
dims
,
active
,
default_rng_value
(
)
)
function
Dropout
(
p
;
dims
=
:
,
rng
=
default_rng_value
(
)
)
@
assert
0
≤
p
≤
1
Dropout
(
p
,
dims
,
nothing
,
rng
)
end
@
functor
Dropout
trainable
(
a
::
Dropout
)
=
(
;
)
function
(
a
::
Dropout
)
(
x
)
_isactive
(
a
)
||
return
x
return
dropout
(
a
.
rng
,
x
,
a
.
p
;
dims
=
a
.
dims
,
active
=
true
)
end
testmode!
(
m
::
Dropout
,
mode
=
true
)
=
(
m
.
active
=
(
isnothing
(
mode
)
||
mode
==
:
auto
)
?
nothing
:
!
mode
;
m
)
function
Base
.
show
(
io
::
IO
,
d
::
Dropout
)
print
(
io
,
"
Dropout(
"
,
d
.
p
)
d
.
dims
!=
(
:
)
&&
print
(
io
,
"
, dims =
$
(
repr
(
d
.
dims
)
)
"
)
print
(
io
,
"
)
"
)
end
"""
AlphaDropout(p; rng = default_rng_value())
A dropout layer. Used in
[Self-Normalizing Neural Networks](https://arxiv.org/abs/1706.02515).
The AlphaDropout layer ensures that mean and variance of activations
remain the same as before.
Does nothing to the input once [`testmode!`](@ref) is true.
# Examples
```jldoctest
julia> using Statistics
julia> x = randn(1000,1);
julia> m = Chain(Dense(1000 => 1000, selu), AlphaDropout(0.2));
julia> Flux.trainmode!(m);
julia> y = m(x);
julia> isapprox(std(x), std(y), atol=0.2)
true
```
"""
mutable
struct
AlphaDropout
{
F
,
R
<:
AbstractRNG
}
p
::
F
active
::
Union
{
Bool
,
Nothing
}
rng
::
R
function
AlphaDropout
(
p
,
active
,
rng
)
@
assert
0
≤
p
≤
1
new
{
typeof
(
p
)
,
typeof
(
rng
)
}
(
p
,
active
,
rng
)
end
end
AlphaDropout
(
p
,
active
)
=
AlphaDropout
(
p
,
active
,
default_rng_value
(
)
)
AlphaDropout
(
p
;
rng
=
default_rng_value
(
)
)
=
AlphaDropout
(
p
,
nothing
,
rng
)
@
functor
AlphaDropout
trainable
(
a
::
AlphaDropout
)
=
(
;
)
function
(
a
::
AlphaDropout
)
(
x
::
AbstractArray
{
T
}
)
where
T
_isactive
(
a
)
||
return
x
p
=
a
.
p
iszero
(
p
)
&&
return
x
isone
(
p
)
&&
return
sign
.
(
x
)
.*
T
(
0
)
α′
=
T
(
-1.7580993408473766
)
# selu(-Inf) == -λα
A
=
T
(
inv
(
sqrt
(
(
1
-
p
)
*
(
1
+
p
*
α′
^
2
)
)
)
)
B
=
T
(
-
A
*
α′
*
p
)
noise
=
rand!
(
a
.
rng
,
similar
(
x
)
)
return
A
.*
ifelse
.
(
noise
.>
p
,
x
,
α′
)
.+
B
end
testmode!
(
m
::
AlphaDropout
,
mode
=
true
)
=
(
m
.
active
=
(
isnothing
(
mode
)
||
mode
==
:
auto
)
?
nothing
:
!
mode
;
m
)
"""
LayerNorm(size..., λ=identity; affine=true, ϵ=1fe-5)
A [normalisation layer](https://arxiv.org/abs/1607.06450) designed to be
used with recurrent hidden states.
The argument `size` should be an integer or a tuple of integers.
In the forward pass, the layer normalises the mean and standard
deviation of the input, then applies the elementwise activation `λ`.
The input is normalised along the first `length(size)` dimensions
for tuple `size`, and along the first dimension for integer `size`.
The input is expected to have first dimensions' size equal to `size`.
If `affine=true`, it also applies a learnable shift and rescaling
using the [`Scale`](@ref) layer.
See also [`BatchNorm`](@ref), [`InstanceNorm`](@ref), [`GroupNorm`](@ref), and [`normalise`](@ref).
# Examples
```jldoctest
julia> using Statistics
julia> xs = rand(3, 3, 3, 2); # a batch of 2 images, each having 3 channels
julia> m = LayerNorm(3);
julia> y = m(xs);
julia> isapprox(std(y, dims=1:3), ones(1, 1, 1, 2), atol=0.1) && std(y, dims=1:3) != std(xs, dims=1:3)
true
```
"""
struct
LayerNorm
{
F
,
D
,
T
,
N
}
λ
::
F
diag
::
D
ϵ
::
T
size
::
NTuple
{
N
,
Int
}
affine
::
Bool
end
function
LayerNorm
(
size
::
Tuple
{
Vararg
{
Int
}
}
,
λ
=
identity
;
affine
::
Bool
=
true
,
ϵ
::
Real
=
1f-5
)
diag
=
affine
?
Scale
(
size
...
,
λ
)
:
λ
!=
identity
?
Base
.
Fix1
(
broadcast
,
λ
)
:
identity
return
LayerNorm
(
λ
,
diag
,
ϵ
,
size
,
affine
)
end
LayerNorm
(
size
::
Integer
...
;
kw
...
)
=
LayerNorm
(
Int
.
(
size
)
;
kw
...
)
LayerNorm
(
size_act
...
;
kw
...
)
=
LayerNorm
(
Int
.
(
size_act
[
1
:
end
-
1
]
)
,
size_act
[
end
]
;
kw
...
)
@
functor
LayerNorm
(
a
::
LayerNorm
)
(
x
)
=
a
.
diag
(
normalise
(
x
,
dims
=
1
:
length
(
a
.
size
)
,
ϵ
=
a
.
ϵ
)
)
function
Base
.
show
(
io
::
IO
,
l
::
LayerNorm
)
print
(
io
,
"
LayerNorm(
"
,
join
(
l
.
size
,
"
,
"
)
)
l
.
λ
===
identity
||
print
(
io
,
"
,
"
,
l
.
λ
)
hasaffine
(
l
)
||
print
(
io
,
"
, affine=false
"
)
print
(
io
,
"
)
"
)
endFor InstanceNorm, GroupNorm, and BatchNorm. Compute the statistics on the slices specified by reduce_dims. reduce_dims=[1,...,N-2,N] for BatchNorm reduce_dims=[1,...,N-2] for InstanceNorm and GroupNorm
function
_norm_layer_forward
(
l
,
x
::
AbstractArray
{
T
,
N
}
;
reduce_dims
,
affine_shape
,
)
where
{
T
,
N
}
if
!
_isactive
(
l
)
&&
l
.
track_stats
# testmode with tracked stats
stats_shape
=
ntuple
(
i
->
i
==
N
-
1
?
size
(
x
,
N
-
1
)
:
1
,
N
)
μ
=
reshape
(
l
.
μ
,
stats_shape
)
σ²
=
reshape
(
l
.
σ²
,
stats_shape
)
else
# trainmode or testmode without tracked stats
μ
=
mean
(
x
;
dims
=
reduce_dims
)
σ²
=
var
(
x
;
mean
=
μ
,
dims
=
reduce_dims
,
corrected
=
false
)
if
l
.
track_stats
_track_stats!
(
l
,
x
,
μ
,
σ²
,
reduce_dims
)
# update moving mean/std
end
end
o
=
_norm_layer_forward
(
x
,
μ
,
σ²
,
l
.
ϵ
)
hasaffine
(
l
)
||
return
l
.
λ
.
(
o
)
γ
=
reshape
(
l
.
γ
,
affine_shape
)
β
=
reshape
(
l
.
β
,
affine_shape
)
return
l
.
λ
.
(
γ
.*
o
.+
β
)
end
@
inline
_norm_layer_forward
(
x
,
μ
,
σ²
,
ϵ
)
=
(
x
.-
μ
)
./
sqrt
.
(
σ²
.+
ϵ
)
function
_track_stats!
(
bn
,
x
::
AbstractArray
{
T
,
N
}
,
μ
,
σ²
,
reduce_dims
,
)
where
{
T
,
N
}
V
=
eltype
(
bn
.
σ²
)
mtm
=
bn
.
momentum
res_mtm
=
one
(
V
)
-
mtm
m
=
prod
(
size
(
x
,
i
)
for
i
in
reduce_dims
)
μnew
=
vec
(
N
∈
reduce_dims
?
μ
:
mean
(
μ
,
dims
=
N
)
)
σ²new
=
vec
(
N
∈
reduce_dims
?
σ²
:
mean
(
σ²
,
dims
=
N
)
)
# ForwardDiff.value removes Dual, was an error, issue #2122
bn
.
μ
.=
value
.
(
res_mtm
.*
bn
.
μ
.+
mtm
.*
μnew
)
bn
.
σ²
.=
value
.
(
res_mtm
.*
bn
.
σ²
.+
mtm
.*
(
m
/
(
m
-
one
(
V
)
)
)
.*
σ²new
)
return
nothing
end
ChainRulesCore
.
@
non_differentiable
_track_stats!
(
::
Any
...
)
"""
BatchNorm(channels::Integer, λ=identity;
initβ=zeros32, initγ=ones32,
affine = true, track_stats = true,
ϵ=1f-5, momentum= 0.1f0)
[Batch Normalization](https://arxiv.org/abs/1502.03167) layer.
`channels` should be the size of the channel dimension in your data (see below).
Given an array with `N` dimensions, call the `N-1`th the channel dimension. For
a batch of feature vectors this is just the data dimension, for `WHCN` images
it's the usual channel dimension.
`BatchNorm` computes the mean and variance for each `D_1×...×D_{N-2}×1×D_N`
input slice and normalises the input accordingly.
If `affine=true`, it also applies a shift and a rescale to the input
through to learnable per-channel bias β and scale γ parameters.
After normalisation, elementwise activation `λ` is applied.
If `track_stats=true`, accumulates mean and var statistics in training phase
that will be used to renormalize the input in test phase.
Use [`testmode!`](@ref) during inference.
# Examples
```julia
julia> using Statistics
julia> xs = rand(3, 3, 3, 2); # a batch of 2 images, each having 3 channels
julia> m = BatchNorm(3);
julia> Flux.trainmode!(m);
julia> isapprox(std(m(xs)), 1, atol=0.1) && std(xs) != std(m(xs))
true
```
"""
mutable
struct
BatchNorm
{
F
,
V
,
N
,
W
}
λ
::
F
# activation function
β
::
V
# bias
γ
::
V
# scale
μ
::
W
# moving mean
σ²
::
W
# moving var
ϵ
::
N
momentum
::
N
affine
::
Bool
track_stats
::
Bool
active
::
Union
{
Bool
,
Nothing
}
chs
::
Int
# number of channels
end
function
BatchNorm
(
chs
::
Int
,
λ
=
identity
;
initβ
=
zeros32
,
initγ
=
ones32
,
affine
=
true
,
track_stats
=
true
,
ϵ
=
1f-5
,
momentum
=
0.1f0
)
β
=
affine
?
initβ
(
chs
)
:
nothing
γ
=
affine
?
initγ
(
chs
)
:
nothing
μ
=
track_stats
?
zeros32
(
chs
)
:
nothing
σ²
=
track_stats
?
ones32
(
chs
)
:
nothing
return
BatchNorm
(
λ
,
β
,
γ
,
μ
,
σ²
,
ϵ
,
momentum
,
affine
,
track_stats
,
nothing
,
chs
)
end
@
functor
BatchNorm
trainable
(
bn
::
BatchNorm
)
=
hasaffine
(
bn
)
?
(
β
=
bn
.
β
,
γ
=
bn
.
γ
)
:
(
;
)
function
(
BN
::
BatchNorm
)
(
x
)
@
assert
size
(
x
,
ndims
(
x
)
-
1
)
==
BN
.
chs
N
=
ndims
(
x
)
reduce_dims
=
[
1
:
N
-
2
;
N
]
affine_shape
=
ntuple
(
i
->
i
==
N
-
1
?
size
(
x
,
N
-
1
)
:
1
,
N
)
return
_norm_layer_forward
(
BN
,
x
;
reduce_dims
,
affine_shape
)
end
testmode!
(
m
::
BatchNorm
,
mode
=
true
)
=
(
m
.
active
=
(
isnothing
(
mode
)
||
mode
==
:
auto
)
?
nothing
:
!
mode
;
m
)
function
Base
.
show
(
io
::
IO
,
l
::
BatchNorm
)
print
(
io
,
"
BatchNorm(
$
(
l
.
chs
)
"
)
(
l
.
λ
==
identity
)
||
print
(
io
,
"
,
$
(
l
.
λ
)
"
)
hasaffine
(
l
)
||
print
(
io
,
"
, affine=false
"
)
print
(
io
,
"
)
"
)
end
"""
InstanceNorm(channels::Integer, λ=identity;
initβ=zeros32, initγ=ones32,
affine=false, track_stats=false,
ϵ=1f-5, momentum=0.1f0)
[Instance Normalization](https://arxiv.org/abs/1607.08022) layer.
`channels` should be the size of the channel dimension in your data (see below).
Given an array with `N > 2` dimensions, call the `N-1`th the channel dimension.
For `WHCN` images it's the usual channel dimension.
`InstanceNorm` computes the mean and variance for each `D_1×...×D_{N-2}×1×1`
input slice and normalises the input accordingly.
If `affine=true`, it also applies a shift and a rescale to the input
through to learnable per-channel bias `β` and scale `γ` parameters.
If `track_stats=true`, accumulates mean and var statistics in training phase
that will be used to renormalize the input in test phase.
**Warning**: the defaults for `affine` and `track_stats` used to be `true`
in previous Flux versions (< v0.12).
# Examples
```jldoctest
julia> using Statistics
julia> xs = rand(3, 3, 3, 2); # a batch of 2 images, each having 3 channels
julia> m = InstanceNorm(3);
julia> y = m(xs);
julia> isapprox(std(y, dims=1:2), ones(1, 1, 3, 2), atol=0.2) && std(y, dims=1:2) != std(xs, dims=1:2)
true
```
"""
mutable
struct
InstanceNorm
{
F
,
V
,
N
,
W
}
λ
::
F
# activation function
β
::
V
# bias
γ
::
V
# scale
μ
::
W
# moving mean
σ²
::
W
# moving var
ϵ
::
N
momentum
::
N
affine
::
Bool
track_stats
::
Bool
active
::
Union
{
Bool
,
Nothing
}
chs
::
Int
# number of channels
end
function
InstanceNorm
(
chs
::
Int
,
λ
=
identity
;
initβ
=
zeros32
,
initγ
=
ones32
,
affine
=
false
,
track_stats
=
false
,
ϵ
=
1f-5
,
momentum
=
0.1f0
)
if
track_stats
Base
.
depwarn
(
"
`track_stats=true` will be removed from InstanceNorm in Flux 0.14. The default value is `track_stats=false`, which will work as before.
"
,
:
InstanceNorm
)
end
β
=
affine
?
initβ
(
chs
)
:
nothing
γ
=
affine
?
initγ
(
chs
)
:
nothing
μ
=
track_stats
?
zeros32
(
chs
)
:
nothing
σ²
=
track_stats
?
ones32
(
chs
)
:
nothing
return
InstanceNorm
(
λ
,
β
,
γ
,
μ
,
σ²
,
ϵ
,
momentum
,
affine
,
track_stats
,
nothing
,
chs
)
end
@
functor
InstanceNorm
trainable
(
in
::
InstanceNorm
)
=
hasaffine
(
in
)
?
(
β
=
in
.
β
,
γ
=
in
.
γ
)
:
(
;
)
function
(
l
::
InstanceNorm
)
(
x
)
@
assert
ndims
(
x
)
>
2
@
assert
size
(
x
,
ndims
(
x
)
-
1
)
==
l
.
chs
N
=
ndims
(
x
)
reduce_dims
=
1
:
N
-
2
affine_shape
=
ntuple
(
i
->
i
==
N
-
1
?
size
(
x
,
N
-
1
)
:
1
,
N
)
return
_norm_layer_forward
(
l
,
x
;
reduce_dims
,
affine_shape
)
end
testmode!
(
m
::
InstanceNorm
,
mode
=
true
)
=
(
m
.
active
=
(
isnothing
(
mode
)
||
mode
==
:
auto
)
?
nothing
:
!
mode
;
m
)
function
Base
.
show
(
io
::
IO
,
l
::
InstanceNorm
)
print
(
io
,
"
InstanceNorm(
$
(
l
.
chs
)
"
)
l
.
λ
==
identity
||
print
(
io
,
"
,
$
(
l
.
λ
)
"
)
hasaffine
(
l
)
||
print
(
io
,
"
, affine=false
"
)
print
(
io
,
"
)
"
)
end
"""
GroupNorm(channels::Integer, G::Integer, λ=identity;
initβ=zeros32, initγ=ones32,
affine=true, track_stats=false,
ϵ=1f-5, momentum=0.1f0)
[Group Normalization](https://arxiv.org/abs/1803.08494) layer.
`chs` is the number of channels, the channel dimension of your input.
For an array of N dimensions, the `N-1`th index is the channel dimension.
`G` is the number of groups along which the statistics are computed.
The number of channels must be an integer multiple of the number of groups.
`channels` should be the size of the channel dimension in your data (see below).
Given an array with `N > 2` dimensions, call the `N-1`th the channel dimension.
For `WHCN` images it's the usual channel dimension.
If `affine=true`, it also applies a shift and a rescale to the input
through to learnable per-channel bias `β` and scale `γ` parameters.
If `track_stats=true`, accumulates mean and var statistics in training phase
that will be used to renormalize the input in test phase.
# Examples
```jldoctest
julia> using Statistics
julia> xs = rand(3, 3, 4, 2); # a batch of 2 images, each having 4 channels
julia> m = GroupNorm(4, 2);
julia> y = m(xs);
julia> isapprox(std(y[:, :, 1:2, 1]), 1, atol=0.1) && std(xs[:, :, 1:2, 1]) != std(y[:, :, 1:2, 1])
true
julia> isapprox(std(y[:, :, 3:4, 2]), 1, atol=0.1) && std(xs[:, :, 3:4, 2]) != std(y[:, :, 3:4, 2])
true
```
"""
mutable
struct
GroupNorm
{
F
,
V
,
N
,
W
}
G
::
Int
# number of groups
λ
::
F
# activation function
β
::
V
# bias
γ
::
V
# scale
μ
::
W
# moving mean
σ²
::
W
# moving std
ϵ
::
N
momentum
::
N
affine
::
Bool
track_stats
::
Bool
active
::
Union
{
Bool
,
Nothing
}
chs
::
Int
# number of channels
end
@
functor
GroupNorm
trainable
(
gn
::
GroupNorm
)
=
hasaffine
(
gn
)
?
(
β
=
gn
.
β
,
γ
=
gn
.
γ
)
:
(
;
)
function
GroupNorm
(
chs
::
Int
,
G
::
Int
,
λ
=
identity
;
initβ
=
zeros32
,
initγ
=
ones32
,
affine
=
true
,
track_stats
=
false
,
ϵ
=
1f-5
,
momentum
=
0.1f0
)
if
track_stats
Base
.
depwarn
(
"
`track_stats=true` will be removed from GroupNorm in Flux 0.14. The default value is `track_stats=false`, which will work as before.
"
,
:
GroupNorm
)
end
chs
%
G
==
0
||
error
(
"
The number of groups (
$
(
G
)
) must divide the number of channels (
$
chs
)
"
)
β
=
affine
?
initβ
(
chs
)
:
nothing
γ
=
affine
?
initγ
(
chs
)
:
nothing
μ
=
track_stats
?
zeros32
(
G
)
:
nothing
σ²
=
track_stats
?
ones32
(
G
)
:
nothing
return
GroupNorm
(
G
,
λ
,
β
,
γ
,
μ
,
σ²
,
ϵ
,
momentum
,
affine
,
track_stats
,
nothing
,
chs
)
end
function
(
gn
::
GroupNorm
)
(
x
)
@
assert
ndims
(
x
)
>
2
@
assert
size
(
x
,
ndims
(
x
)
-
1
)
==
gn
.
chs
N
=
ndims
(
x
)
sz
=
size
(
x
)
x
=
reshape
(
x
,
sz
[
1
:
N
-
2
]
...
,
sz
[
N
-
1
]
÷
gn
.
G
,
gn
.
G
,
sz
[
N
]
)
N
=
ndims
(
x
)
reduce_dims
=
1
:
N
-
2
affine_shape
=
ntuple
(
i
->
i
∈
(
N
-
1
,
N
-
2
)
?
size
(
x
,
i
)
:
1
,
N
)
x
=
_norm_layer_forward
(
gn
,
x
;
reduce_dims
,
affine_shape
)
return
reshape
(
x
,
sz
)
end
testmode!
(
m
::
GroupNorm
,
mode
=
true
)
=
(
m
.
active
=
(
isnothing
(
mode
)
||
mode
==
:
auto
)
?
nothing
:
!
mode
;
m
)
function
Base
.
show
(
io
::
IO
,
l
::
GroupNorm
)
# print(io, "GroupNorm($(join(size(l.β), ", "))", ", ", l.G)
print
(
io
,
"
GroupNorm(
$
(
l
.
chs
)
,
$
(
l
.
G
)
"
)
l
.
λ
==
identity
||
print
(
io
,
"
,
"
,
l
.
λ
)
hasaffine
(
l
)
||
print
(
io
,
"
, affine=false
"
)
print
(
io
,
"
)
"
)
end
"""
hasaffine(l)
Return `true` if a normalisation layer has trainable shift and
scale parameters, `false` otherwise.
See [`BatchNorm`](@ref), [`InstanceNorm`](@ref), [`GroupNorm`](@ref), and [`LayerNorm`](@ref).
"""
hasaffine
(
l
::
Union
{
BatchNorm
,
InstanceNorm
,
LayerNorm
,
GroupNorm
}
)
=
l
.
affine