Add Serde to CountVectorizer, to export and import it about linfa

[YuhanLiin]

I don't think CountVectorizer has serde support but it should be pretty easy to add. Can you post your code snippet just to be sure?

[Bastian1110]

Sure !
This is the code Im using to "export" a model using ciborium, this method has worked successfully with linfa-svm .

// In the winequality SVM example after "fiting" the SVM model

let model_value = cbor!(model).unwrap();
let mut vec_model = Vec::new();
let _cebor_writer = ciborium::ser::into_writer(&model_value, &mut vec_model);

//Esporting it to a .cbor file
let path: &Path = Path::new("./model.cbor");
fs::write(path, vec_model).unwrap();

Then, you can import the model and use it, like this :

//Reading the .cbor file and converting it to a ciborium value
let mut file = File::open("./model.cbor").unwrap();
let mut data: Vec<u8> = Vec::new();
file.read_to_end(&mut data).unwrap();
let model_value = ciborium::de::from_reader::<Value, _>(&data[..]).unwrap();

//Creating again the model, but its already trained 
let model: Svm<f64, bool> = model_value.deserialized().unwrap();
println!("{}", model);

This really works with ease (with the SVM-model), but the way I find out that a model doesn't support serde serialization is by trying to pass it to the cbor! macro, when a model does not support serialization, the following error appears:

the trait bound `<MODELNAME>: serde::ser::Serialize` is not satisfied
the following other types implement trait `serde::ser::Serialize`:
  &'a T
  &'a mut T
  ()
  (T0, T1)
  . . .

[Bastian1110]

I just cloned your repository with the addition of serde support, thank you very much!
I tried to test it inside the extra-serde branch, my test was the same as described in the other comment, I tried to pass the CountVectorizer through the cbor! macro but I get the same error:

//In the countvectorization.rs example of linfa-preprocessing (inside the extra-serve branch)

let vectorizer_value = cbor!(vectorizer).unwrap();

But the following error occurs :

the trait bound `CountVectorizer: serde::ser::Serialize` is not satisfied
the following other types implement trait `serde::ser::Serialize`:
  &'a T
  &'a mut T
  ()
  (T0, T1)

Maybe Im testing it wrong? If so, any other idea on how to test it without merging to the master branch?

[YuhanLiin]

Did you enable the serde feature on the crate?

[YuhanLiin]

I just tested with the serde feature enabled and I asserted that CountVectorizer: Serialize holds. I'm going to merge the PR into master and you can test it from there.

[Bastian1110]

I just tested adding the serde to the features in Cargo.toml and it works!
Thanks a lot!