it.uniroma2.sag.kelp.kernel.cache

Class DynamicIndexKernelCache

java.lang.Object

it.uniroma2.sag.kelp.kernel.cache.KernelCache

it.uniroma2.sag.kelp.kernel.cache.DynamicIndexKernelCache

All Implemented Interfaces:

Serializable

public class DynamicIndexKernelCache
extends KernelCache
implements Serializable

Cache for kernel computations. It can stores all the pairwise kernel computations among any set of examples with cardinality not exceeding the exampleToStore parameter. It is the optimal solution when all the pairwise kernel computations between all the examples in the datasets can be simultaneously stored in cache, but examples IDs are not consecutive making FixIndexKernelCache not working. Given a number of examples to store m, the memory occupation is about m*(m+1)/2 floats = m*(m+1)*2B it uses a Least Recently Used policy when free space is required

Author:

Simone Filice

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DynamicIndexKernelCache()
DynamicIndexKernelCache(int examplesToStore) Initializes a DynamicIndexKernelCache that can contain all the possible pairwise kernel computations between up to examplesToStore examples

Method Summary

Methods

Modifier and Type	Method and Description
void	flushCache() Empties the cache
int	getExamplesToStore() Returns the maximum number of examples whose pairwise kernel computations can be simultaneously stored
protected Float	getStoredKernelValue(Example exA, Example exB) Retrieves in the cache the kernel operation between two examples
void	setExamplesToStore(int examplesToStore) Sets the maximum number of examples whose pairwise kernel computations can be simultaneously stored
void	setKernelValue(Example exA, Example exB, float value) Stores a kernel computation in cache

Methods inherited from class it.uniroma2.sag.kelp.kernel.cache.KernelCache

getCacheHits, getCacheMisses, getKernelValue, resetCacheStats

Methods inherited from class java.lang.Object

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

Constructor Detail

DynamicIndexKernelCache

public DynamicIndexKernelCache(int examplesToStore)

Initializes a DynamicIndexKernelCache that can contain all the possible pairwise kernel computations between up to examplesToStore examples

Parameters:

examplesToStore - the maximum number of examples whose pairwise kernel computations can be simultaneously stored

DynamicIndexKernelCache

public DynamicIndexKernelCache()

Method Detail

getExamplesToStore

public int getExamplesToStore()

Returns the maximum number of examples whose pairwise kernel computations can be simultaneously stored

Returns:

the examplesToStore

setExamplesToStore

public void setExamplesToStore(int examplesToStore)

Sets the maximum number of examples whose pairwise kernel computations can be simultaneously stored

Parameters:

examplesToStore - the examplesToStore to set

NOTE: all the already stored kernel computations will be lost

getStoredKernelValue

protected Float getStoredKernelValue(Example exA,
                         Example exB)

Description copied from class: KernelCache

Retrieves in the cache the kernel operation between two examples

Specified by:

getStoredKernelValue in class KernelCache

Parameters:

exA - the first example

exB - the second example

Returns:

the kernel similarity, null<\code> if a cache miss occurs

setKernelValue

public void setKernelValue(Example exA,
                  Example exB,
                  float value)

Description copied from class: KernelCache

Stores a kernel computation in cache

Specified by:

setKernelValue in class KernelCache

Parameters:

exA - the first example

exB - the second example

value - the kernel value to be stored in cache

flushCache

public void flushCache()

Description copied from class: KernelCache

Empties the cache

Specified by:

flushCache in class KernelCache