/*
* Copyright 2016 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
module.exports = function(kernelP) {
return (function() {
var Utils = require('../../utils.js');
var PipelineStage = require('../PipelineStage.js')();
var gKernelP = kernelP;
/**
* @classdesc
* Class for indexing categorical feature columns in a dataset of {@link Vector}.
*
* This has 2 usage modes:
* - Automatically identify categorical features (default behavior)
* - This helps process a dataset of unknown vectors into a dataset with some continuous
* features and some categorical features. The choice between continuous and categorical
* is based upon a maxCategories parameter.
* - Set maxCategories to the maximum number of categorical any categorical feature should have.
* - E.g.: Feature 0 has unique values {-1.0, 0.0}, and feature 1 values {1.0, 3.0, 5.0}.
* If maxCategories = 2, then feature 0 will be declared categorical and use indices {0, 1},
* and feature 1 will be declared continuous.
* - Index all features, if all features are categorical
* - If maxCategories is set to be very large, then this will build an index of unique
* values for all features.
* - Warning: This can cause problems if features are continuous since this will collect ALL
* unique values to the driver.
* - E.g.: Feature 0 has unique values {-1.0, 0.0}, and feature 1 values {1.0, 3.0, 5.0}.
* If maxCategories >= 3, then both features will be declared categorical.
*
* This returns a model which can transform categorical features to use 0-based indices.
*
* Index stability:
* - This is not guaranteed to choose the same category index across multiple runs.
* - If a categorical feature includes value 0, then this is guaranteed to map value 0 to index 0.
* This maintains vector sparsity.
* - More stability may be added in the future.
*
* TODO: Future extensions: The following functionality is planned for the future:
* - Preserve metadata in transform; if a feature's metadata is already present, do not recompute.
* - Specify certain features to not index, either via a parameter or via existing metadata.
* - Add warning if a categorical feature has only 1 category.
* - Add option for allowing unknown categories.
* @class
* @extends module:eclairjs/ml.PipelineStage
* @memberof module:eclairjs/ml/feature
* @param {string} [uid]
*/
function VectorIndexer() {
Utils.handleConstructor(this, arguments, gKernelP);
}
VectorIndexer.prototype = Object.create(PipelineStage.prototype);
VectorIndexer.prototype.constructor = VectorIndexer;
/**
* An immutable unique ID for the object and its derivatives.
* @returns {Promise.<string>}
*/
VectorIndexer.prototype.uid = function () {
var args = {
target: this,
method: 'uid',
args: Utils.wrapArguments(arguments),
returnType: String
};
return Utils.generate(args);
};
/**
* @param {number} value
* @returns {module:eclairjs/ml/feature.VectorIndexer}
*/
VectorIndexer.prototype.setMaxCategories = function(value) {
var args = {
target: this,
method: 'setMaxCategories',
args: Utils.wrapArguments(arguments),
returnType: VectorIndexer
};
return Utils.generate(args);
};
/**
* @param {string} value
* @returns {module:eclairjs/ml/feature.VectorIndexer}
*/
VectorIndexer.prototype.setInputCol = function(value) {
var args = {
target: this,
method: 'setInputCol',
args: Utils.wrapArguments(arguments),
returnType: VectorIndexer
};
return Utils.generate(args);
};
/**
* @param {string} value
* @returns {module:eclairjs/ml/feature.VectorIndexer}
*/
VectorIndexer.prototype.setOutputCol = function(value) {
var args = {
target: this,
method: 'setOutputCol',
args: Utils.wrapArguments(arguments),
returnType: VectorIndexer
};
return Utils.generate(args);
};
/**
* @param {module:eclairjs/sql.Dataset} dataset
* @returns {module:eclairjs/ml/feature.VectorIndexerModel}
*/
VectorIndexer.prototype.fit = function(dataset) {
var VectorIndexerModel = require('./VectorIndexerModel')();
var args = {
target: this,
method: 'fit',
args: Utils.wrapArguments(arguments),
returnType: VectorIndexerModel
};
return Utils.generate(args);
};
/**
* @param {module:eclairjs/sql/types.StructType} schema
* @returns {module:eclairjs/sql/types.StructType}
*/
VectorIndexer.prototype.transformSchema = function(schema) {
var StructType = require('../../sql/types/StructType.js')();
var args = {
target: this,
method: 'transformSchema',
args: Utils.wrapArguments(arguments),
returnType: StructType
};
return Utils.generate(args);
};
/**
* @param {module:eclairjs/ml/param.ParamMap} extra
* @returns {module:eclairjs/ml/feature.VectorIndexer}
*/
VectorIndexer.prototype.copy = function(extra) {
var args = {
target: this,
method: 'transformSchema',
args: Utils.wrapArguments(arguments),
returnType: VectorIndexer
};
return Utils.generate(args);
};
//
// static methods
//
/**
* @param {string} path
* @returns {module:eclairjs/ml/feature.VectorIndexer}
*/
VectorIndexer.load = function(path) {
var args = {
target: VectorIndexerModel,
method: 'load',
kernelP: gKernelP,
static: true,
args: Utils.wrapArguments(arguments),
returnType: VectorIndexer
};
return Utils.generate(args);
};
VectorIndexer.moduleLocation = '/ml/feature/VectorIndexer';
return VectorIndexer;
})();
};