tech.ml.dataset

Dataset and ETL pipeline for machine learning. Datasets are currently in-memory columnwise databases. The backing store behind tech.ml.dataset is tablesaw. Further support is intended in the near future for Apache Arrow.

An example of using the dataset for advanced regression techniques.

Dataset Pipeline Processing

Dataset ETL is a repeatable processing that stores data so that doing inference later is automatic.

1. Build your ETL pipeline.
2. Apply to training dataset. Result is a new pipeline with things that min,max per column stored or even trained models.
3. Train, gridsearch, get a model.
4. Use ETL pipeline returned from (2) with no modification to apply to new inference samples.
5. Infer.

Example

user> (require '[tech.ml.dataset.etl :as etl])
nil
user> (require '[tech.ml.dataset :as dataset])
nil
user> (require '[clojure.edn :as edn])
nil
user> (require '[clojure.java.io :as io])
nil
user> (require '[camel-snake-kebab.core :refer [->kebab-case]])
nil
user> (require '[clojure.string :as s])
nil

user> (def mapseq-fruit-dataset
  (memoize
   (fn []
     (let [fruit-ds (slurp (io/resource "fruit_data_with_colors.txt"))
           dataset (->> (s/split fruit-ds #"\n")
                        (mapv #(s/split % #"\s+")))
           ds-keys (->> (first dataset)
                        (mapv (comp keyword ->kebab-case)))]
       (->> (rest dataset)
            (map (fn [ds-line]
                   (->> ds-line
                        (map (fn [ds-val]
                               (try
                                 (Double/parseDouble ^String ds-val)
                                 (catch Throwable e
                                   (-> (->kebab-case ds-val)
                                       keyword)))))
                        (zipmap ds-keys)))))))))
#'user/mapseq-fruit-dataset
user> (take 3 (mapseq-fruit-dataset))
({:color-score 0.55,
  :fruit-label 1.0,
  :fruit-name :apple,
  :fruit-subtype :granny-smith,
  :height 7.3,
  :mass 192.0,
  :width 8.4}
 {:color-score 0.59,
  :fruit-label 1.0,
  :fruit-name :apple,
  :fruit-subtype :granny-smith,
  :height 6.8,
  :mass 180.0,
  :width 8.0}
 {:color-score 0.6,
  :fruit-label 1.0,
  :fruit-name :apple,
  :fruit-subtype :granny-smith,
  :height 7.2,
  :mass 176.0,
  :width 7.4})
...


user> (def etl-source-pipeline '[[remove [:fruit-subtype :fruit-label]]
                                 [string->number string?]
                                 ;;Range numeric data to -1 1
                                 [range-scaler (not categorical?)]])
#'user/etl-source-pipeline
user> (def pipeline-result (etl/apply-pipeline (mapseq-fruit-dataset)
                                               etl-source-pipeline
                                               {:target :fruit-name}))
#'user/pipeline-result
user> (:options pipeline-result)

user> (:options pipeline-result)
{:dataset-column-metadata {:post-pipeline [{:categorical? true,
                                            :datatype :float64,
                                            :name :fruit-name,
                                            :size 59,
                                            :target? true}
                                           {:datatype :float64, :name :mass, :size 59}
                                           {:datatype :float64, :name :width, :size 59}
                                           {:datatype :float64, :name :height, :size 59}
                                           {:datatype :float64,
                                            :name :color-score,
                                            :size 59}],
                           :pre-pipeline [{:datatype :float32,
                                           :name :fruit-label,
                                           :size 59}
                                          {:categorical? true,
                                           :datatype :string,
                                           :name :fruit-name,
                                           :size 59}
                                          {:categorical? true,
                                           :datatype :string,
                                           :name :fruit-subtype,
                                           :size 59}
                                          {:datatype :float32, :name :mass, :size 59}
                                          {:datatype :float32, :name :width, :size 59}
                                          {:datatype :float32, :name :height, :size 59}
                                          {:datatype :float32,
                                           :name :color-score,
                                           :size 59}]},
 :feature-columns [:color-score :height :mass :width],
 :label-columns [:fruit-name],
 :label-map {:fruit-name {"apple" 0, "lemon" 2, "mandarin" 3, "orange" 1}},
 :target :fruit-name}
user> (:pipeline pipeline-result)
[{:context {}, :operation [remove [:fruit-subtype :fruit-label]]}
 {:context {:label-map {:fruit-name {"apple" 0, "lemon" 2, "mandarin" 3, "orange" 1}}},
  :operation [string->number (:fruit-name)]}
 {:context {:color-score {:max 0.9300000071525574, :min 0.550000011920929},
            :height {:max 10.5, :min 4.0},
            :mass {:max 362.0, :min 76.0},
            :width {:max 9.600000381469727, :min 5.800000190734863}},
  :operation [range-scaler #{:color-score :height :mass :width}]}]
user> (clojure.pprint/print-table (->> (dataset/->flyweight (:dataset pipeline-result))
                                       (take 10)))

| :fruit-name |                :mass |               :width |               :height |        :color-score |
|-------------+----------------------+----------------------+-----------------------+---------------------|
|         0.0 | -0.18881118881118886 |  0.36842068278560225 |  0.015384674072265625 |                -1.0 |
|         0.0 |  -0.2727272727272727 |  0.15789457833668674 |  -0.13846147977388823 |  -0.789473882342312 |
|         0.0 | -0.30069930069930073 | -0.15789482930359944 | -0.015384674072265625 | -0.7368420392192294 |
|         3.0 |  -0.9300699300699301 |  -0.7894738955510845 |   -0.7846154433030348 | 0.31578949019519276 |
|         3.0 |  -0.9440559440559441 |  -0.8947369477755422 |   -0.8153846447284405 |  0.2631579607807706 |
|         3.0 |   -0.972027972027972 |                 -1.0 |   -0.9076922490046575 | 0.15789458824326608 |
|         3.0 |   -0.972027972027972 |  -0.9473684738877711 |   -0.9076922490046575 |  0.3684210196096147 |
|         3.0 |                 -1.0 |                 -1.0 |                  -1.0 |  0.3684210196096147 |
|         0.0 | -0.28671328671328666 |  -0.3157896586071989 |   0.16923082791841937 |   0.947368470585578 |
|         0.0 | -0.32867132867132864 | -0.15789482930359944 |  -0.07692307692307687 |  0.7894735686336514 |
nil

ETL Language Design

The ETL language is currently an implicit piping of a list of dataset->dataset transformations.

Each operator involves a column selection and then an operation, thus there are three sub-languages defined:

• Column Selection - column-filters.md.
• Math Operations - math-ops.md.
• Pipeline Operators - pipeline-operators.md.

Extension

There is an extensive protocol hierarchy for supporting different data stores. You can buy into the hierarchy at several levels:

• dataset.
• column and then use the generic table
• implementation.

The current system is built on top of support for the tech.datatype subsystem which is described on our blog. You can see the datatype-level bindings to fastutil and tablesaw. These bindings enable generic and highly optimized simple transformations as well as enabling the tensor subsystem to operate on the base data in-place efficiently.

Thanks to the integration of datatype, tech.compute, and jna, most operations are optimized. Especially math and transformations.

The tablesaw column-level bindings are here. They use the generic table support and as such they do not use the actual tablesaw 'table' datatype.

License

Copyright © 2019 Complements of TechAscent, LLC

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.