# Undefined variable error in Julia: UndefVarError:castnot defined
**URL:** https://discourse.julialang.org/t/undefined-variable-error-in-julia-undefvarerror-castnot-defined/108190
**Category:** New to Julia
**Tags:** question, cuda, flux
**Created:** [December 30, 2023, 1:55pm UTC](https://discourse.julialang.org/t/undefined-variable-error-in-julia-undefvarerror-castnot-defined/108190 "2023-12-30T13:55:26Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Mallikarjuna\_G\_B](https://discourse.julialang.org/u/Mallikarjuna_G_B)
#### Post date: [December 30, 2023, 1:55pm UTC](https://discourse.julialang.org/t/undefined-variable-error-in-julia-undefvarerror-castnot-defined/108190/1 "2023-12-30T13:55:26Z")
**Description:**
I’m trying to build a transformer-based classifier model in Julia using the TransformersLite package, but I’m encountering an error that says `UndefVarError:`cast`not defined`. I’ve updated all of the packages in my environment, but the error persists.
UndefVarError: `cast` not defined
1. (::Main.var"workspace#5".var"#1#2")(::Int64)@_none:0_
2. **iterate** @_generator.jl:47_ [inlined]
3. **collect** (::Base.Generator{UnitRange{Int64}, Main.var"workspace#5".var"#1#2"})@_array.jl:782_
4. **top-level scope** @_[Local: 11](http://localhost:1234/edit?id=db9fdbee-a716-11ee-2d19-fd32ebd263d9#)_
“”"
begin
```
dim_embedding = hyperparameters["dim_embedding"]
pdrop = hyperparameters["pdrop"]
n_heads = hyperparameters["n_heads"]
dim_feedforward = hyperparameters["dim_feedforward"]
embed = Embed(dim_embedding, length(indexer))
pos_enc = PositionEncoding(dim_embedding)
dropout = Dropout(pdrop)
transformer_blocks = [
TransformerEncoderBlock(n_heads, dim_embedding, dim_feedforward, pdrop=pdrop, act=relu) |>
cast(TransformersLite.TransformerEncoderBlock)
for _ in 1:n_heads]
flatten_layer = FlattenLayer()
final_dense = Dense(dim_embedding * max_length, nlabels)
# Construct the model
model = TransformersLite.TransformerClassifier(embed, pos_enc, dropout,
transformer_blocks, flatten_layer, final_dense)
display(model)
println("")
# Adjust for GPU or CPU
device = CUDA.has_cuda() && CUDA.functional() ? gpu : cpu
model = device(model)
hyperparameters["model"] = "$(typeof(model).name. Wrapper)"
hyperparameters["trainable parameters"] = sum(length, Flux.params(model))
# Define loss and accuracy functions
if nlabels == 1
loss(x, y) = Flux.logitbinarycrossentropy(x, y)
accuracy(ŷ, y) = mean((Flux.sigmoid.(ŷ) .> 0.5) .== y)
else
loss = Flux.logitcrossentropy
accuracy(ŷ, y) = mean(Flux.onecold(ŷ) .== Flux.onecold(y))
end
end
```
“”"
**Steps taken to troubleshoot:**
1. I updated all of the packages in my Julia environment using `Pkg.update()`.
2. I cleared the Julia cache using `Pkg.reset()`.
3. I checked for conflicting packages using `Pkg.conflicts()`.
4. I verified package versions using `Pkg.status()`.
5. I inspected the code carefully for any potential errors or inconsistencies.
**I have also tried reinstalling the `Pkg` package, restarting Julia, and updating Julia to the latest version, but the error persists.**
I would be grateful for any help you can provide in resolving this issue.
**Thank you!**
---
### Author:  [@nsajko](https://discourse.julialang.org/u/nsajko)
#### Post date: [December 30, 2023, 2:10pm UTC](https://discourse.julialang.org/t/undefined-variable-error-in-julia-undefvarerror-castnot-defined/108190/2 "2023-12-30T14:10:22Z")
Please read this topic:
> [@Please read: make it easier to help you](https://discourse.julialang.org/t/please-read-make-it-easier-to-help-you/14757):
>
> Welcome to the Julia Discourse! We are enthusiastic about helping Julia programmers, both beginner and experienced. This public service announcement (PSA) outlines best practices when asking for help. Following these points makes it easier for us to help you and more likely you’ll get a prompt, useful answer. Keywords are highlighted to make it easier to refer to specific points. Choose a descriptive title that captures the key part of your question, eg “plots with multiple axes” instead of …
In particular, format your code properly.
---
### Author:  [@Jeff\_Emanuel](https://discourse.julialang.org/u/Jeff_Emanuel)
#### Post date: [December 30, 2023, 4:17pm UTC](https://discourse.julialang.org/t/undefined-variable-error-in-julia-undefvarerror-castnot-defined/108190/3 "2023-12-30T16:17:36Z")
You are trying to call a function nameed `cast`. Julia `Base` does not have a function named `cast`. Are you expecting it from one of the packages you are using? Did you derive your code from an example? If so, perhaps the example is based on older packages. HTH
Your post would probably get more attention in the New to Julia or a specific domain category.