# AssertionError GCNConv FeaturedGraph GeometricFlux

**URL:** <https://discourse.julialang.org/t/assertionerror-gcnconv-featuredgraph-geometricflux/66061>\
**Category:** Machine Learning\
**Tags:** question, package, flux\
**Created:** [August 9, 2021, 7:33am UTC](https://discourse.julialang.org/t/assertionerror-gcnconv-featuredgraph-geometricflux/66061 "2021-08-09T07:33:53Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![riegel\_gestr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/riegel_gestr/32/20431_2.png) [@riegel\_gestr](https://discourse.julialang.org/u/riegel_gestr)\
**Post date:** [August 9, 2021, 7:33am UTC](https://discourse.julialang.org/t/assertionerror-gcnconv-featuredgraph-geometricflux/66061/1 "2021-08-09T07:33:53Z")

</div>

I am trying the GeometricFlux library by doing some test (coming from torch\_geometric).  
So test that I am doing is a simple graphs classification and I have considered very simple input:

```julia
N = 100
k = 10
g = erdos_renyi(N,float(k)/N)
a = Matrix{Float32}(adjacency_matrix(g))
features = Matrix{Float32}(1.0*I,(N,N))
train_data = (FeaturedGraph(a,features), labels)

```

and `labels` is a `OneHotVector` from Flux, keeping track that this is a Erdos-graph (just an example).  
Clearly here train\_data is just a `Tuple` but in the following code will be a list of tuple (many graphs).  
The following code is the graph-classification, just the train part:

```julia
num_nodes = 100
num_features = 100
hidden = 50
hidden_second = 15
epochs = 100
@load "data/train_data.jld2" train_data
model = Chain(
            GCNConv(num_features => hidden),
            GCNConv(hidden => hidden_second),
            )
loss(x,y) = logitcrossentropy(model(x),y)
ps = Flux.params(model)
opt = ADAM(0.01)
@showprogress for epoch in 1:epochs
    for (x,y) in train_data
        gs = Flux.gradient(ps) do
            j = model(x)
            ŷ = mean(j.nf,dims = 2)
            loss(ŷ, y)
        end
    end
    Flux.Optimise.update!(opt, ps, gs)
end

```

This code give me back the following `AssertionError`:

```julia
ERROR: AssertionError: A GCNConv created without a graph must be given a FeaturedGraph as an input.
Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0 [inlined]
  [2] _pullback(ctx::Zygote.Context, f::typeof(throw), args::AssertionError)
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:9
  [3] _pullback
    @ ~/.julia/packages/GeometricFlux/kwwxb/src/layers/conv.jl:60 [inlined]
  [4] _pullback(ctx::Zygote.Context, f::GCNConv{Float32, typeof(identity), NullGraph}, args::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0
  [5] _pullback
    @ ~/.julia/packages/Flux/qp1gc/src/layers/basic.jl:36 [inlined]
  [6] _pullback(::Zygote.Context, ::typeof(Flux.applychain), ::Tuple{GCNConv{Float32, typeof(identity), NullGraph}, GCNConv{Float32, typeof(identity), NullGraph}}, ::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0
  [7] _pullback
    @ ~/.julia/packages/Flux/qp1gc/src/layers/basic.jl:38 [inlined]
  [8] _pullback(ctx::Zygote.Context, f::Chain{Tuple{GCNConv{Float32, typeof(identity), NullGraph}, GCNConv{Float32, typeof(identity), NullGraph}}}, args::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0
  [9] _pullback
    @ ./REPL[16]:1 [inlined]
 [10] _pullback(::Zygote.Context, ::typeof(loss), ::Matrix{Float32}, ::Flux.OneHotArray{UInt32, 11, 0, 1, UInt32})
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0
 [11] _pullback
    @ ./REPL[20]:6 [inlined]
 [12] _pullback(::Zygote.Context, ::var"#3#4"{Flux.OneHotArray{UInt32, 11, 0, 1, UInt32}, FeaturedGraph{Matrix{Float32}, Matrix{Float32}, FillArrays.Fill{Float32, 2, Tuple{Base.OneTo{Int64}, Base.OneTo{Int64}}}, FillArrays.Fill{Float32, 1, Tuple{Base.OneTo{Int64}}}}})
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface2.jl:0
 [13] pullback(f::Function, ps::Zygote.Params)
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface.jl:343
 [14] gradient(f::Function, args::Zygote.Params)
    @ Zygote ~/.julia/packages/Zygote/TaBlo/src/compiler/interface.jl:75
 [15] macro expansion
    @ REPL[20]:3 [inlined]
 [16] top-level scope
    @ ~/.julia/packages/ProgressMeter/Vf8un/src/ProgressMeter.jl:940

```

I don’t understand if I have to add something in the middle, because if I do `model(train_data[1][1])` for example I get no error

---

<div class="post-metadata">

**Author:** ![riegel\_gestr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/riegel_gestr/32/20431_2.png) [@riegel\_gestr](https://discourse.julialang.org/u/riegel_gestr)\
**Post date:** [August 13, 2021, 7:09am UTC](https://discourse.julialang.org/t/assertionerror-gcnconv-featuredgraph-geometricflux/66061/2 "2021-08-13T07:09:24Z")

</div>

Solved.  
Wrong typo in the loss function.

```julia
loss(x,y) = logitcrossentropy(model(x),y)

```

into:

```julia
loss(x,y) = logitcrossentropy(mean(model(x).nf, dims = 2),y)

```