Hi all,

first time I’m trying to use PINNs with Julia, as I’m reading the docs there are some parts that I’m missing.

In this example :

I see that the lines used for the predictions are:

```
phi = discretization.phi
u_predict = reshape([first(phi([x,y],res.u)) for x in xs for y in ys],(length(xs),length(ys)))
```

However, in this example, the predictions are calculated like this:

```
phi = discretization.phi
depvars = [:u,:w]
minimizers_ = [res.u.depvar[depvars[i]] for i in 1:length(chain)]
u_predict = [[phi[i]([t,x], minimizers_[i])[1] for t in ts for x in xs] for i in 1:2]
```

Can someone explain to me the difference between the two `u_predict`

lines? I’m not sure I’m following just by reading the docs.

My other question is about the `phi`

object, what does it contain exactly? Is it the trained network?