Package org.apache.sysds.utils

Class MemoryEstimates

java.lang.Object

org.apache.sysds.utils.MemoryEstimates

public class MemoryEstimates
extends Object

Memory Estimates is a helper class containing static classes that estimate the memory requirements of different types of objects in java. All estimates are worst case JVM x86-64bit uncompressed object pointers. This in practice means that the objects are most commonly smaller, for instance the object references are often time. If the memory pressure is low (there is a low number of allocated objects) then object pointers are 4 bits.

Constructor Summary

Constructors

Constructor	Description
MemoryEstimates()

Method Summary

Modifier and Type	Method	Description
static long	bitSetCost(int length)	Get the worst case memory usage of an java.util.BitSet java object.
static long	byteArrayCost(int length)	Get the worst case memory usage of an array of bytes.
static long	charArrayCost(int length)	Get the worst case memory usage of an array of chars.
static double	doubleArrayCost(long length)	Get the worst case memory usage of an array of doubles.
static double	intArrayCost(long length)	Get the worst case memory usage of an array of integers.
static double	longArrayCost(int length)	Get the worst case memory usage for an array of longs
static double	objectArrayCost(long length)	Get the worst case memory usage for an array of objects.

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryEstimates

public MemoryEstimates()

Method Detail

bitSetCost

public static long bitSetCost(int length)

Get the worst case memory usage of an java.util.BitSet java object.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

byteArrayCost

public static long byteArrayCost(int length)

Get the worst case memory usage of an array of bytes.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

charArrayCost

public static long charArrayCost(int length)

Get the worst case memory usage of an array of chars.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

intArrayCost

public static double intArrayCost(long length)

Get the worst case memory usage of an array of integers.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

doubleArrayCost

public static double doubleArrayCost(long length)

Get the worst case memory usage of an array of doubles.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

objectArrayCost

public static double objectArrayCost(long length)

Get the worst case memory usage for an array of objects.

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes

longArrayCost

public static double longArrayCost(int length)

Get the worst case memory usage for an array of longs

Parameters:

length - The length of the array.

Returns:

The memory estimate in bytes