scicloj.ml.core — scicloj/scicloj.ml 0.1.0-beta2

Core functions for machine learninig and pipeline execution.

Functions are re-exported from:

• scicloj.metamorph.ml.*
• scicloj.metamorph.core

->pipeline clj

(->pipeline ops)

(->pipeline config ops)

Create pipeline from declarative description.

categorical clj

(categorical value-vec)

Given a vector a categorical values create a gridsearch definition.

classification-accuracy clj

(classification-accuracy lhs rhs)

correct/total. Model output is a sequence of probability distributions. label-seq is a sequence of values. The answer is considered correct if the key highest probability in the model output entry matches that label.

classification-loss clj

(classification-loss lhs rhs)

1.0 - classification-accuracy.

confusion-map clj

(confusion-map predicted-labels labels)

(confusion-map predicted-labels labels normalize)

confusion-map->ds clj

(confusion-map->ds conf-matrix-map)

(confusion-map->ds conf-matrix-map normalize)

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-seq clj

define-model! clj

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

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.

evaluate-pipelines clj

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

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

Evaluates performance of a seq of metamorph pipelines, which are suposed to have a model as last step, which behaves correctly in mode :fit and :transform It calculates the loss, given as loss-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.

• pipe-fn-seq need to be sequence of functions which follow the metamorph approach. They should take as input the metamorph context map, which has the dataset under key :metamorph/data, manipulate it as needed for the transformation pipeline and read and write only to the context as needed. These type of functions get produced typically by calling scicloj.metamorph/pipeline

• 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. tableclot.api/split->seq produces such splits.

• metric-fn Metric function to use. Typically comming from tech.v3.ml.loss loss-or-accuracy If the metric-fn is a loss or accuracy calculation. Can be :loss or :accuracy.

• options map controls some mainly performance related parameters, which are:

  • :result-dissoc-in-seq - Controls how much information is returned for each cross validation. We call dissoc-in on every seq of this for the fit-ctx and transform-ctx before returning them. Default is

  [[:fit-ctx :metamorph/data]
   [:fit-ctx :scicloj.metamorph.ml/target-ds]
   [:transform-ctx :metamorph/data]
   [:transform-ctx :scicloj.metamorph.ml/target-ds]
   [:transform-ctx :scicloj.metamorph.ml/feature-ds]]
  

  • :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) or pmap (:pmap) to map over different pipelines. Default :pmap
  • :evaluation-handler-fn - Gets called once with the complete result of an evluation step. Its return alue is ignre ande default i a noop.

This function expects as well the ground truth of the target variable into a specific key in the context :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

hyperparameters clj

(hyperparameters model-kwd)

Get the hyperparameters for this model definition

lift clj

(lift op & params)

Create context aware version of the given op function. :metamorph/data will be used as a first parameter.

Result of the op function will be stored under :metamorph/data

linear clj

(linear start end)

(linear start end n-steps)

(linear start end n-steps res-dtype-or-space)

Create a gridsearch definition which does a linear search.

• res-dtype-or-space map be either a datatype keyword or a vector of categorical values.

mae clj

(mae predictions labels)

mean absolute error

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

mse clj

(mse predictions labels)

mean squared error

options->model-def clj

(options->model-def options)

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

pipeline clj

(pipeline & ops)

probability-distributions->labels clj

(probability-distributions->labels prob-dists)

rmse clj

(rmse predictions labels)

root mean squared error

sobol-gridsearch clj

(sobol-gridsearch opt-map)

(sobol-gridsearch opt-map start-idx)

Given an map of key->values where some of the values are gridsearch definitions produce a sequence of fully defined maps.

user> (require '[tech.v3.ml.gridsearch :as ml-gs])
nil
user> (def opt-map  {:a (ml-gs/categorical [:a :b :c])
                     :b (ml-gs/linear 0.01 1 10)
                     :c :not-searched})
user> opt-map
{:a
 {:tech.v3.ml.gridsearch/type :linear,
  :start 0.0,
  :end 2.0,
  :n-steps 3,
  :result-space [:a :b :c]}
  ...

user> (ml-gs/sobol-gridsearch opt-map)
({:a :b, :b 0.56, :c :not-searched}
 {:a :c, :b 0.22999999999999998, :c :not-searched}
 {:a :b, :b 0.78, :c :not-searched}
...

thaw-model clj

(thaw-model model)

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

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 preduct 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.