Flux -- decompose layers + parameters?

[ToucheSir]

@BLI

In the old system, I could pick out layer no. i by md.layers[i] .
→ Am I right in that this has been replaced by md[i] ?

Nope, you can still do md.layers[i] if md is a Chain. md[i] is definitely preferred though.

@BLI

In the old system, I could pick bias vector b and weight matrix W by md.b.data and md.W.data .
→ Am I right in that now, I do par = params(md) and then par[i]
for i in 1:2:end gives the bias vectors b , while par[i] for i in 2:2:end gives the weight matrices W ?

Because Flux no longer uses Tracker, you can just reference md.b and md.W directly. params is mostly useful as a way around listing every single parameter array in a model when calling gradient.

@BLI

In the old version of Flux , it was a little tricky to specify the data type of the bias vectors and weight matrices.
→ Is this simpler, now?

Do you mean e.g. Float64 vs Float32? Flux now has helper functions that will allow you to convert a layer or an entire model’s weights between both (f64 and f32 respectively).