de.lmu.ifi.dbs.elki.persistent
Class OnDiskUpperTriangleMatrix

java.lang.Object
  de.lmu.ifi.dbs.elki.persistent.OnDiskUpperTriangleMatrix

public class OnDiskUpperTriangleMatrix
extends Object

Class representing an upper triangle matrix backed by an on-disk array of O((n+1)*n/2) size

Author:

Erich Schubert

Field Summary

private OnDiskArray	array Data storage
private int	matrixsize Size of the matrix
private static long	serialVersionUID Serial number, also used for generating a magic
private static int	TRIANGLE_HEADER_SIZE Size of this class' header

Constructor Summary

OnDiskUpperTriangleMatrix(File filename, int magicseed, int extraheadersize, int recordsize, boolean writable)
Constructor to access an existing array.

OnDiskUpperTriangleMatrix(File filename, int magicseed, int extraheadersize, int recordsize, int matrixsize)
Constructor to access a new array.

Method Summary

private static int	arraysize(int matrixsize) Compute the size of the needed backing array from the matrix dimensions.
void	close() Close the matrix file.
private int	computeOffset(int x, int y) Compute the offset within the file.
int	getMatrixSize() Query the size of the matrix.
byte[]	readRecord(int x, int y) Get data from the matrix
void	resizeMatrix(int newsize) Resize the matrix to cover newsize x newsize.
void	writeRecord(int x, int y, byte[] data) Put data into the matrix

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

Serial number, also used for generating a magic

See Also:

Constant Field Values

TRIANGLE_HEADER_SIZE

private static final int TRIANGLE_HEADER_SIZE

Size of this class' header

See Also:

Constant Field Values

matrixsize

private int matrixsize

Size of the matrix

array

private OnDiskArray array

Data storage

Constructor Detail

OnDiskUpperTriangleMatrix

public OnDiskUpperTriangleMatrix(File filename,
                                 int magicseed,
                                 int extraheadersize,
                                 int recordsize,
                                 boolean writable)
                          throws IOException

Constructor to access an existing array.

Parameters:

filename - File name

magicseed - Magic number

extraheadersize - Size of extra header data

recordsize - Record size

writable - flag to open writable

Throws:

IOException

OnDiskUpperTriangleMatrix

public OnDiskUpperTriangleMatrix(File filename,
                                 int magicseed,
                                 int extraheadersize,
                                 int recordsize,
                                 int matrixsize)
                          throws IOException

Constructor to access a new array.

Parameters:

filename - File name

magicseed - Magic number

extraheadersize - Size of extra header data

recordsize - Record size

matrixsize - Size of matrix to store

Throws:

IOException

Method Detail

resizeMatrix

public void resizeMatrix(int newsize)
                  throws IOException

Resize the matrix to cover newsize x newsize.

Parameters:

newsize - New matrix size.

Throws:

IOException

arraysize

private static int arraysize(int matrixsize)

Compute the size of the needed backing array from the matrix dimensions.

Parameters:

matrixsize - size of the matrix

Returns:

size of the array

computeOffset

private int computeOffset(int x,
                          int y)

Compute the offset within the file.

Parameters:

x - First coordinate

y - Second coordinate

Returns:

Linear offset

readRecord

public byte[] readRecord(int x,
                         int y)
                  throws IOException

Get data from the matrix

Parameters:

x - First coordinate

y - Second coordinate

Returns:

record raw data

Throws:

IOException

writeRecord

public void writeRecord(int x,
                        int y,
                        byte[] data)
                 throws IOException

Put data into the matrix

Parameters:

x - First coordinate

y - Second coordinate

data - Data

Throws:

IOException

close

public void close()
           throws IOException

Close the matrix file.

Throws:

IOException

getMatrixSize

public int getMatrixSize()

Query the size of the matrix.

Returns:

size of the matrix