Loading Model Code

Once the name of a model, and the package providing that model, have been identified (see Model Search) one can either import the model type interactively with @iload, as shown under Installation, or use @load as shown below. The @load macro works from within a module, a package or a function, provided the relevant package providing the MLJ interface has been added to your package environment.

In general, the code providing core functionality for the model (living in a packge you should consult for documentation) may be different from the package providing the MLJ interface. Since the core package is a dependency of the interface package, only the interface package needs to be added to your environment.

For instance, suppose you have activated a Julia package environment my_env that you wish to use for your MLJ project; for example you have run:

using Pkg
Pkg.activate("my_env", shared=true)

And, furthermore, suppose you want to use DecisionTreeClassifier, provided by the DecisionTree.jl package. Then, to determine which package provides the MLJ interface you call load_path:

julia> load_path("DecisionTreeClassifier", pkg="DecisionTree")

In this case we see that the package required is MLJDecisionTreeInterface.jl. If this package is not in my_env (do Pkg.status() to check) you add it by running

julia> Pkg.add("MLJDecisionTreeInterface");

So long as my_env is the active environment, this action need never be repeated (unless you run Pkg.rm("MLJDecisionTreeInterface")). You are now ready to instantiate a decision tree classifier:

julia> Tree = @load DecisionTree pkg=DecisionTree
julia> tree = Tree()

which is equivalent to

julia> import MLJDecisionTreeInterface.DecisionTreeClassifier
julia> Tree = MLJDecisionTreeInterface.DecisionTreeClassifier()
julia> tree = Tree()

Tip. The specification pkg=... above can be dropped for the many models that are provided by only a single package.


load_path(model::String, pkg=nothing)

Return the load path for model type with name model, specifying the package name pkg to resolve name conflicts if necessary.


Return the load path of a model instance or type. Usually requires necessary model code to have been separately loaded. Supply a string as above if code is not loaded.

@load ModelName pkg=nothing verbosity=0 add=false

Import the model type the model named in the first argument into the calling module, specfying pkg in the case of an ambiguous name (to packages providing a model type with the same name). Returns the model type.

Warning In older versions of MLJ/MLJModels, @load returned an instance instead.

To automatically add required interface packages to the current environment, specify add=true. For interactive loading, use @iload instead.


Tree = @load DecisionTreeRegressor
tree = Tree()
tree2 = Tree(min_samples_split=6)

SVM = @load SVC pkg=LIBSVM
svm = SVM()

See also @iload

@iload ModelName

Interactive alternative to @load. Provides user with an optioin to install (add) the required interface package to the current environment, and to choose the relevant model-providing package in ambiguous cases. See @load