DataVec Reductions

Available reductions


GeographicMidpointReduction

[source]

delimiter is configurable), determine the geographic midpoint. See “geographic midpoint” at: http://www.geomidpoint.com/methods.html For implementation algorithm, see: http://www.geomidpoint.com/calculation.html

transform
public Schema transform(Schema inputSchema) 
  • param delim Delimiter for the coordinates in text format. For example, if format is “lat,long” use “,”

StringReducer

[source]

A StringReducer is used to take a set of examples and reduce them. The idea: suppose you have a large number of columns, and you want to combine/reduce the values in each column.
StringReducer allows you to specify different reductions for differently for different columns: min, max, sum, mean etc.

Uses are: (1) Reducing examples by a key (2) Reduction operations in time series (windowing ops, etc)

transform
public Schema transform(Schema schema) 

Get the output schema, given the input schema

outputColumnName
public Builder outputColumnName(String outputColumnName) 

Create a StringReducer builder, and set the default column reduction operation. For any columns that aren’t specified explicitly, they will use the default reduction operation. If a column does have a reduction operation explicitly specified, then it will override the default specified here.

  • param defaultOp Default reduction operation to perform
appendColumns
public Builder appendColumns(String... columns) 

Reduce the specified columns by taking the minimum value

prependColumns
public Builder prependColumns(String... columns) 

Reduce the specified columns by taking the maximum value

mergeColumns
public Builder mergeColumns(String... columns) 

Reduce the specified columns by taking the sum of values

replaceColumn
public Builder replaceColumn(String... columns) 

Reduce the specified columns by taking the mean of the values

customReduction
public Builder customReduction(String column, ColumnReduction columnReduction) 

Reduce the specified column using a custom column reduction functionality.

  • param column Column to execute the custom reduction functionality on
  • param columnReduction Column reduction to execute on that column
setIgnoreInvalid
public Builder setIgnoreInvalid(String... columns) 

When doing the reduction: set the specified columns to ignore any invalid values. Invalid: defined as being not valid according to the ColumnMetaData: {- link ColumnMetaData#isValid(Writable)}. For numerical columns, this typically means being unable to parse the Writable. For example, Writable.toLong() failing for a Long column. If the column has any restrictions (min/max values, regex for Strings etc) these will also be taken into account.

  • param columns Columns to set ‘ignore invalid’ for

API Reference

API Reference

Detailed API docs for all libraries including DL4J, ND4J, DataVec, and Arbiter.

Examples

Examples

Explore sample projects and demos for DL4J, ND4J, and DataVec in multiple languages including Java and Kotlin.

Tutorials

Tutorials

Step-by-step tutorials for learning concepts in deep learning while using the DL4J API.

Guide

Guide

In-depth documentation on different scenarios including import, distributed training, early stopping, and GPU setup.

Deploying models? There's a tool for that.