# References for network construction via symbolic\_discretize

**URL:** <https://discourse.julialang.org/t/references-for-network-construction-via-symbolic-discretize/102541>\
**Category:** General Usage\
**Tags:** question, neural-network, lux\
**Created:** [August 6, 2023, 10:43pm UTC](https://discourse.julialang.org/t/references-for-network-construction-via-symbolic-discretize/102541 "2023-08-06T22:43:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Ethan\_Tran](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ethan_tran/32/49198_2.png) [@Ethan\_Tran](https://discourse.julialang.org/u/Ethan_Tran)\
**Post date:** [August 6, 2023, 10:43pm UTC](https://discourse.julialang.org/t/references-for-network-construction-via-symbolic-discretize/102541/1 "2023-08-06T22:43:53Z")

</div>

I used the NeuralPDE to solve the ODE system by following the tutorial at [NeuralPDE.jl](https://neuralpde.sciml.ai/stable/). I used the construction with the Lux.jl package, which is presented at [Defining Systems of PDEs for Physics-Informed Neural Networks (PINNs)](https://neuralpde.sciml.ai/stable/tutorials/systems/).  
In the Direct Construction via symbolic\_discretize section, the loss function can take apart the pieces and reassemble them using the `symbolic_discretize` interface, and there is a difference between the construction of Lux and Flux packages. I would like to understand the network construction of two of them, but the tutorial just provides the following information: **" Notice here that the solution is represented in the `OptimizationSolution` with `u` as the parameters for the trained neural network. But, for the case where the neural network is from Lux.jl, it’s given as a `ComponentArray` where `res.u.depvar.x` corresponds to the result for the neural network corresponding to the dependent variable `x` , i.e. `res.u.depvar.u1` are the trained parameters for `phi[1]` in our example. For simpler indexing, you can use `res.u.depvar[:u1]` or `res.u.depvar[Symbol(:u,1)]` as shown here."**. Would you please provide me the references for these two packages when using the `symbolic_discretize` interface?  
Thank you all.