ca.pfv.spmf.algorithms.sequentialpatterns.prefixSpan_AGP.items

Class PseudoSequence

java.lang.Object

ca.pfv.spmf.algorithms.sequentialpatterns.prefixSpan_AGP.items.PseudoSequence

public class PseudoSequence
extends java.lang.Object

This class represents a sequence from a projected database (as based in PrefixSpan). Since it is a projected sequence, it makes reference to the original sequence. This class is inspired in SPMF PrefixSpan implementation. Copyright Antonio Gomariz Peñalver 2013 This file is part of the SPMF DATA MINING SOFTWARE (http://www.philippe-fournier-viger.com/spmf). SPMF is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. SPMF is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with SPMF. If not, see .

Constructor Summary

Constructors

Constructor and Description
PseudoSequence(long timeShift, PseudoSequence pseudosequence, int itemsetIndex, int itemIndex, int firstItemset) It make a pseudosequence from a previous pseudosequence.
PseudoSequence(long timeShift, Sequence sequence, int itemsetIndex, int itemIndex) PseudoSequence made from a starndard sequence.

Method Summary

Modifier and Type	Method and Description
void	addProjectionPoint(int firstItemset, long timeShift, PseudoSequence pseudosequence, int itemsetIndex, int itemIndex) Method to make a projection in a pseudosequence already projected.
long	getAbsoluteTimeStamp(int itemsetIndex, int firstItemset) It obtains the original timestamp for that itemset
int	getBeginningOfItemset(int firstItem, int itemsetIndex) It returns the first item of the first itemset of the specified projection
int	getFirstItemset(int index) It returns the first itemset of the projection, in absolute terms
int	getId() Get the pseudosequence ID
Item	getItemAtInItemsetAt(int firstItem, int itemIndex, int itemsetIndex) Get a given item of an itemset
Itemset	getItemset(int itemsetIndex, int firstitemset) It gets the itemset in the original sequence.
long	getRelativeTimeStamp(int itemsetIndex, int firstItemset) It obtains the relative timestamp
int	getSizeOfItemsetAt(int firstItemset, int index) It returns the size of the itemset in a specified projection of the sequence
long	getTimeShift(int firstItemset) It gets the timeShift for a specified projection of the pseudosequence
int	indexOf(int firstItemset, int itemsetIndex, Item item) It returns the index where an item appears in the specified itemset of the specified projection of the current pseudosequence.
boolean	isFirstItemset(int index) To know if an itemset is the first one
boolean	isPostfix(int firstItem, int itemsetIndex) It informs if a projection it starts in the midle of an itemset
int	numberOfProjectionsIncluded() It returns the number of projections included in this pseudosequence
int	size(int i) It returns the size for the current pseudosequence
java.lang.String	toString() Get the string representation of this pseudosequence

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PseudoSequence

public PseudoSequence(long timeShift,
                      PseudoSequence pseudosequence,
                      int itemsetIndex,
                      int itemIndex,
                      int firstItemset)

It make a pseudosequence from a previous pseudosequence. Therefore, we are making a projection in a previous projection and we have to take into account the previous index of that projection to establish the ours.

Parameters:

timeShift - The time shift of the new pseudosequence

pseudosequence - The pseudosequence where we make another projection

itemsetIndex - The itemset index where our new projection is starting

itemIndex - The item index where our new projection is starting

firstItemset - An index that indicates in which projection of the previous pseudoseuqence we are making the new pseudosequence

PseudoSequence

public PseudoSequence(long timeShift,
                      Sequence sequence,
                      int itemsetIndex,
                      int itemIndex)

PseudoSequence made from a starndard sequence. Its purpose is make possible the later projections

Parameters:

timeShift - The original timeshift (Normally, it will be 0)

sequence - The original standard sequence

itemsetIndex - The itemset index where the projection it starts

itemIndex - The item index where the projection it starts

Method Detail

addProjectionPoint

public void addProjectionPoint(int firstItemset,
                               long timeShift,
                               PseudoSequence pseudosequence,
                               int itemsetIndex,
                               int itemIndex)

Method to make a projection in a pseudosequence already projected. In this way, for a same pseudosequence, we can have several projections. For example, let us think in a sequence A = (a) (a b) (a b c). If we project by item a, we obtain three different projections: 1) (a b) (a b c) 2) (*b) (a b c) 3) (*b c) That we do is to put all the three projections in the same pseudoseuqence, and we refers each projection with an index. We call to every projection, projection point.

Parameters:

firstItemset - The projection point of the given pseudosequence where we are making our new projection

timeShift - The given timeshift for our projection

pseudosequence - The given pseudosequence where we are making our projection

itemsetIndex - The itemset index where our projection it starts

itemIndex - The item index where our projection it starts

getFirstItemset

public int getFirstItemset(int index)

It returns the first itemset of the projection, in absolute terms

Parameters:

index - the ith projection in which we want to know the first itemset

Returns:

the item at position index in the first itemset

size

public int size(int i)

It returns the size for the current pseudosequence

Parameters:

i - the ith projection in which we want to know the size

Returns:

the size

numberOfProjectionsIncluded

public int numberOfProjectionsIncluded()

It returns the number of projections included in this pseudosequence

Returns:

the number of projections

getSizeOfItemsetAt

public int getSizeOfItemsetAt(int firstItemset,
                              int index)

It returns the size of the itemset in a specified projection of the sequence

Parameters:

firstItemset - the ith projection in which we are interested

index - The ith itemset of the current pseudosequence

Returns:

the size

getBeginningOfItemset

public int getBeginningOfItemset(int firstItem,
                                 int itemsetIndex)

It returns the first item of the first itemset of the specified projection

Parameters:

firstItem - the specified projection in which we are interested

itemsetIndex - the itemset of the pseudosequence in which we are interested

Returns:

the item

isPostfix

public boolean isPostfix(int firstItem,
                         int itemsetIndex)

It informs if a projection it starts in the midle of an itemset

Parameters:

firstItem - The projection in which we are interested

itemsetIndex - The itemset to study

Returns:

true if it does. otherwise, false.

isFirstItemset

public boolean isFirstItemset(int index)

To know if an itemset is the first one

Parameters:

index - the position of the itemset

Returns:

true if it is the first one, otherwise false

getItemAtInItemsetAt

public Item getItemAtInItemsetAt(int firstItem,
                                 int itemIndex,
                                 int itemsetIndex)

Get a given item of an itemset

Parameters:

firstItem - The projection in which are interested

itemIndex - The item index

itemsetIndex - The itemset index

Returns:

the item

getAbsoluteTimeStamp

public long getAbsoluteTimeStamp(int itemsetIndex,
                                 int firstItemset)

It obtains the original timestamp for that itemset

Parameters:

itemsetIndex - the itemset index for the pseudosequence

firstItemset - the projection in which we are interested

Returns:

the timestamp

getRelativeTimeStamp

public long getRelativeTimeStamp(int itemsetIndex,
                                 int firstItemset)

It obtains the relative timestamp

Parameters:

itemsetIndex - the itemset index

firstItemset - the projection in which we are interested

Returns:

the timestamp

getItemset

public Itemset getItemset(int itemsetIndex,
                          int firstitemset)

It gets the itemset in the original sequence.

Parameters:

itemsetIndex - the itemset index

firstitemset - the projection in which we are interested

Returns:

the itemset

getId

public int getId()

Get the pseudosequence ID

Returns:

the ID

toString

public java.lang.String toString()

Get the string representation of this pseudosequence

Overrides:

toString in class java.lang.Object

Returns:

the string representation

indexOf

public int indexOf(int firstItemset,
                   int itemsetIndex,
                   Item item)

It returns the index where an item appears in the specified itemset of the specified projection of the current pseudosequence. If the item does not appear, it returns -1.

Parameters:

firstItemset - the index of the firstItemset to search

itemsetIndex - the current itemset index

item - the item

Returns:

the index or -1 if the item does not appear

getTimeShift

public long getTimeShift(int firstItemset)

It gets the timeShift for a specified projection of the pseudosequence

Parameters:

firstItemset - the projection in which we are interested

Returns:

the timeshift