org.datavec.api.transform.reduce.impl

Class GeographicMidpointReduction

java.lang.Object

org.datavec.api.transform.reduce.impl.GeographicMidpointReduction

All Implemented Interfaces:

Serializable, ColumnOp, AggregableColumnReduction

public class GeographicMidpointReduction
extends Object
implements AggregableColumnReduction

Given a set of latitude/longitude coordinates, encoded in Text writables with format "lat,long" (the 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

Author:

Alex Black

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GeographicMidpointReduction.AverageCoordinateReduceOp

Field Summary

Fields

Modifier and Type	Field and Description
static double	EDGE_CASE_EPS

Constructor Summary

Constructors

Constructor and Description
GeographicMidpointReduction(String delim)
GeographicMidpointReduction(String delim, String newColumnName)

Method Summary

Modifier and Type	Method and Description
String	columnName() Returns a singular column name this op is meant to run on
String[]	columnNames() Returns column names this op is meant to run on
List<ColumnMetaData>	getColumnOutputMetaData(List<String> newColumnName, ColumnMetaData columnInputMeta) Post-reduce: what is the metadata (type, etc) for this column? For example: a "count unique" operation on a String (StringMetaData) column would return an Integer (IntegerMetaData) column
List<String>	getColumnsOutputName(String columnInputName) Post-reduce: what is the name of the column? For example, "myColumn" -> "mean(myColumn)"
Schema	getInputSchema() Getter for input schema
String	outputColumnName() The output column name after the operation has been applied
String[]	outputColumnNames() The output column names This will often be the same as the input
IAggregableReduceOp<Writable,List<Writable>>	reduceOp() Reduce a single column.
void	setInputSchema(Schema inputSchema) Set the input schema.
Schema	transform(Schema inputSchema) Get the output schema for this transformation, given an input schema

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EDGE_CASE_EPS

public static final double EDGE_CASE_EPS

See Also:

Constant Field Values

Constructor Detail

GeographicMidpointReduction

public GeographicMidpointReduction(String delim)

Parameters:

delim - Delimiter for the coordinates in text format. For example, if format is "lat,long" use ","

GeographicMidpointReduction

public GeographicMidpointReduction(String delim,
                                   String newColumnName)

Method Detail

reduceOp

public IAggregableReduceOp<Writable,List<Writable>> reduceOp()

Description copied from interface: AggregableColumnReduction

Reduce a single column. Note: The List<Writable> here is a single column in a reduction window, and NOT the single row (as is usually the case for List<Writable> instances

Specified by:

reduceOp in interface AggregableColumnReduction

Returns:

Writable containing the reduced data

getColumnsOutputName

public List<String> getColumnsOutputName(String columnInputName)

Description copied from interface: AggregableColumnReduction

Post-reduce: what is the name of the column? For example, "myColumn" -> "mean(myColumn)"

Specified by:

getColumnsOutputName in interface AggregableColumnReduction

Parameters:

columnInputName - Name of the column before reduction

Returns:

Name of the column after the reduction

getColumnOutputMetaData

public List<ColumnMetaData> getColumnOutputMetaData(List<String> newColumnName,
                                                    ColumnMetaData columnInputMeta)

Description copied from interface: AggregableColumnReduction

Post-reduce: what is the metadata (type, etc) for this column? For example: a "count unique" operation on a String (StringMetaData) column would return an Integer (IntegerMetaData) column

Specified by:

getColumnOutputMetaData in interface AggregableColumnReduction

columnInputMeta - Metadata for the column, before reduce

Returns:

Metadata for the column, after the reduction

transform

public Schema transform(Schema inputSchema)

Description copied from interface: ColumnOp

Get the output schema for this transformation, given an input schema

Specified by:

transform in interface ColumnOp

setInputSchema

public void setInputSchema(Schema inputSchema)

Description copied from interface: ColumnOp

Set the input schema.

Specified by:

setInputSchema in interface ColumnOp

getInputSchema

public Schema getInputSchema()

Description copied from interface: ColumnOp

Getter for input schema

Specified by:

getInputSchema in interface ColumnOp

Returns:

outputColumnName

public String outputColumnName()

Description copied from interface: ColumnOp

The output column name after the operation has been applied

Specified by:

outputColumnName in interface ColumnOp

Returns:

the output column name

outputColumnNames

public String[] outputColumnNames()

Description copied from interface: ColumnOp

The output column names This will often be the same as the input

Specified by:

outputColumnNames in interface ColumnOp

Returns:

the output column names

columnNames

public String[] columnNames()

Description copied from interface: ColumnOp

Returns column names this op is meant to run on

Specified by:

columnNames in interface ColumnOp

Returns:

columnName

public String columnName()

Description copied from interface: ColumnOp

Returns a singular column name this op is meant to run on

Specified by:

columnName in interface ColumnOp

Returns: