scicloj.metamorph.ml — scicloj/metamorph.ml 0.7.8

default-loss-fn clj

(default-loss-fn dataset)

Given a datset which must have exactly 1 inference target column return a default loss fn. If column is categorical, loss is tech.v3.ml.loss/classification-loss, else the loss is tech.v3.ml.loss/mae (mean average error).

default-result-dissoc-in-fn clj

(default-result-dissoc-in-fn result)

default-result-dissoc-in-seq clj

define-model! clj

(define-model! model-kwd
               train-fn
               predict-fn
               {:keys [hyperparameters thaw-fn explain-fn options documentation
                       unsupervised?]
                :as opts})

Create a model definition. An ml model is a function that takes a dataset and an options map and returns a model. A model is something that, combined with a dataset, produces a inferred dataset.

ensemble-pipe clj

(ensemble-pipe pipes)

Creates an ensemble pipeline function out of various pipelines. The different predictions get combined via majority voting. Can be used in the same way as any other pipeline.

evaluate-pipelines clj

(evaluate-pipelines pipe-fn-seq train-test-split-seq metric-fn loss-or-accuracy)

(evaluate-pipelines pipe-fn-or-decl-seq
                    train-test-split-seq
                    metric-fn
                    loss-or-accuracy
                    options)

Evaluates the performance of a seq of metamorph pipelines, which are suposed to have a model as last step under key :model, which behaves correctly in mode :fit and :transform. The function scicloj.metamorph.ml/model is such function behaving correctly.

This function calculates the accuracy or loss, given as metric-fn of each pipeline in pipeline-fn-seq using all the train-test splits given in train-test-split-seq.

It runs the pipelines in mode :fit and in mode :transform for each pipeline-fn in pipe-fn-seq for each split in train-test-split-seq.

The function returns a seq of seqs of evaluation results per pipe-fn per train-test split. Each of the evaluation results is a context map, which is specified in the malli schema attached to this function.

• pipe-fn-or-decl-seq need to be sequence of pipeline functions or pipline declarations which follow the metamorph approach. These type of functions get produced typically by calling scicloj.metamorph/pipeline. Documentation is here:

• train-test-split-seq need to be a sequence of maps containing the train and test dataset (being tech.ml.dataset) at keys :train and :test. tablecloth.api/split->seq produces such splits. Supervised models require both keys (:train and :test), while unsupervised models only use :train

• metric-fn Metric function to use. Typically comming from tech.v3.ml.loss. For supervised models the metric-fn receives the trueth and predicted values and should return a single double number. For unsupervised models the function receives the fitted ctx and should return a singel double number as well. This metric will be used to sort and eventualy filter the result, depending on the options (:return-best-pipeline-only and :return-best-crossvalidation-only). The notion of best comes from metric-fn combined with loss-and-accuracy

• loss-or-accuracy If the metric-fn is a loss or accuracy calculation. Can be :loss or :accuracy. Decided the notion of best model. In case of :loss pipelines with lower metric are better, in case of :accuracy pipelines with higher value are better.

• options map controls some mainly performance related parameters. These function can potentialy result in a large ammount of data, able to bring the JVM into out-of-memory. We can control how many details the function returns by the following parameter: The default are quite aggresive in removing details, and this can be tweaked further into more or less details via:

  • :return-best-pipeline-only - Only return information of the best performing pipeline. Default is true.

  • :return-best-crossvalidation-only - Only return information of the best crossvalidation (per pipeline returned). Default is true.

  • :map-fn - Controls parallelism, so if we use map (:map) , pmap (:pmap) or :mapv to map over different pipelines. Default :pmap

  • :evaluation-handler-fn - Gets called once with the complete result of an individual pipeline evaluation. It can be used to adapt the data returned for each evaluation and / or to make side effects using the evaluatio data. The result of this function is taken as evaluation result. It need to contain as a minumum this 2 key paths: [:train-transform :metric] [:test-transform :metric] All other evalution data can be removed, if desired.

    It can be used for side effects as well, like experiment tracking on disk. The passed in evaluation result is a map with all information on the current evaluation, including the datasets used.

    The default handler function is: scicloj.metamorph.ml/default-result-dissoc--in-fn which removes the often large model object and the training data. identity can be use to get all evaluation data. scicloj.metamorph.ml/result-dissoc-in-seq--all reduces even more agressively.

  • :other-metrices Specifies other metrices to be calculated during evaluation

This function expects as well the ground truth of the target variable into a specific key in the context at key :model :scicloj.metamorph.ml/target-ds See here for the simplest way to set this up: https://github.com/behrica/metamorph.ml/blob/main/README.md The function [[scicloj.ml.metamorph/model]] does this correctly.

explain clj

(explain model & [options])

Explain (if possible) an ml model. A model explanation is a model-specific map of data that usually indicates some level of mapping between features and importance

get-categorical-maps clj

(get-categorical-maps ds)

hyperparameters clj

(hyperparameters model-kwd)

Get the hyperparameters for this model definition

model clj

(model options)

Executes a machine learning model in train/predict (depending on :mode) from the metamorph.ml model registry.

The model is passed between both invocation via the shared context ctx in a key (a step indentifier) which is passed in key :metamorph/id and guarantied to be unique for each pipeline step.

The function writes and reads into this common context key.

Options:

• :model-type - Keyword for the model to use

Further options get passed to train functions and are model specific.

See here for an overview for the models build into scicloj.ml:

https://scicloj.github.io/scicloj.ml-tutorials/userguide-models.html

Other libraries might contribute other models, which are documented as part of the library.

metamorph	.
Behaviour in mode :fit	Calls scicloj.metamorph.ml/train using data in :metamorph/data and optionsand stores trained model in ctx under key in :metamorph/id
Behaviour in mode :transform	Reads trained model from ctx and calls scicloj.metamorph.ml/predict with the model in $id and data in :metamorph/data
Reads keys from ctx	In mode :transform : Reads trained model to use for prediction from key in :metamorph/id.
Writes keys to ctx	In mode :fit : Stores trained model in key $id and writes feature-ds and target-ds before prediction into ctx at :scicloj.metamorph.ml/feature-ds /:scicloj.metamorph.ml/target-ds

See as well:

• scicloj.metamorph.ml/train
• scicloj.metamorph.ml/predict

model-definition-names clj

(model-definition-names)

Return a list of all registered model defintion names.

model-definitions* clj

Map of model kwd to model definition

options->model-def clj

(options->model-def options)

Return the model definition that corresponse to the :model-type option

predict clj

(predict dataset model)

Predict returns a dataset with only the predictions in it.

• For regression, a single column dataset is returned with the column named after the target
• For classification, a dataset is returned with a float64 column for each target value and values that describe the probability distribution.

result-dissoc-in-seq--all clj

result-dissoc-in-seq--all-fn clj

(result-dissoc-in-seq--all-fn result)

result-dissoc-in-seq--ctxs clj

result-dissoc-in-seq-ctx-fn clj

(result-dissoc-in-seq-ctx-fn result)

score clj

(score predictions-ds trueth-ds target-column-name metric-fn other-metrices)

thaw-model clj

(thaw-model model)

(thaw-model model {:keys [thaw-fn] :as opts})

Thaw a model. Model's returned from train may be 'frozen' meaning a 'thaw' operation is needed in order to use the model. This happens for you during predict but you may also cached the 'thawed' model on the model map under the ':thawed-model' keyword in order to do fast predictions on small datasets.

train clj

(train dataset options)

Given a dataset and an options map produce a model. The model-type keyword in the options map selects which model definition to use to train the model. Returns a map containing at least:

• :model-data - the result of that definitions's train-fn.
• :options - the options passed in.
• :id - new randomly generated UUID.
• :feature-columns - vector of column names.
• :target-columns - vector of column names.