Class Table

java.lang.Object

algorithm.Table

public class Table
extends Object

A very minimal transposition table implementation for df-B*.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	Table.Metrics

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BYTES_PER_ENTRY

Constructor Summary

Constructors

Constructor	Description
Table(int keySize)	Creates a transposition table with a specified size.

Method Summary

Modifier and Type	Method	Description
static int	byteSizeOfTable(int keySize)
void	clear()
void	countRetrieval()
int	getKey(long hash)
Table.Metrics	getMetrics()
static Table	getTable()
static Table	getTable(int keySize)
static Table	getTable(SearchAlgorithm.Limits space_limit)
boolean	hasEntry(int key)
long	hash(int key)
boolean	isPresent(long hash)
int	keySize()
static int	keySizeForByteLimit(long byteLimit)
static int	keySizeForLimit(int entryLimit)
static int	log2fast(int x)
double	lower(int key)
double	lower(long hash)
void	putInTable(long hash, double lower, double upper)
void	setExperimentalBoundsSaving(boolean set_value)	Whether to save the tightest bounds among both entries when a collision leads to the same node.
static int	sizeOfTable(int keySize)
double	upper(int key)
double	upper(long hash)

Methods inherited from class java.lang.Object

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

Field Details

BYTES_PER_ENTRY

public static final int BYTES_PER_ENTRY

See Also:

• Constant Field Values

Constructor Details

Table

public Table(int keySize)

Creates a transposition table with a specified size.

Parameters:

keySize - Determines the size of this table. Typically good between 18 and 25, depending on available memory. For practical reasons, this is capped at 30 and can not be less than 0.

Method Details

getTable

public static Table getTable(SearchAlgorithm.Limits space_limit)

getTable

public static Table getTable()

getTable

public static Table getTable(int keySize)

clear

public void clear()

getKey

public int getKey(long hash)

isPresent

public boolean isPresent(long hash)

Parameters:

hash -

Returns:

true if there is a value present with the same hash as the provided hash, false otherwise

hasEntry

public boolean hasEntry(int key)

Parameters:

key -

Returns:

true if there is a value present at the specified key, false otherwise

lower

public double lower(long hash)

lower

public double lower(int key)

upper

public double upper(long hash)

upper

public double upper(int key)

hash

public long hash(int key)

countRetrieval

public void countRetrieval()

getMetrics

public Table.Metrics getMetrics()

putInTable

public void putInTable(long hash,
 double lower,
 double upper)

setExperimentalBoundsSaving

public void setExperimentalBoundsSaving(boolean set_value)

Whether to save the tightest bounds among both entries when a collision leads to the same node. If false, we instead just save the entry with the smallest range.

Parameters:

set_value - defaults to false

keySize

public int keySize()

sizeOfTable

public static int sizeOfTable(int keySize)

byteSizeOfTable

public static int byteSizeOfTable(int keySize)

keySizeForLimit

public static int keySizeForLimit(int entryLimit)

keySizeForByteLimit

public static int keySizeForByteLimit(long byteLimit)

log2fast

public static int log2fast(int x)

Parameters:

x - a positive number

Returns:

The integer logarithm of x (rounded down), or 0 if x < 1