public class

SmallFloat

extends Object
java.lang.Object
   ↳ org.apache.lucene.util.SmallFloat

Class Overview

Floating point numbers smaller than 32 bits.

Summary

Public Constructors
SmallFloat()
Public Methods
static float byte315ToFloat(byte b)
byteToFloat(b, mantissaBits=3, zeroExponent=15)
static float byte52ToFloat(byte b)
byteToFloat(b, mantissaBits=5, zeroExponent=2)
static float byteToFloat(byte b, int numMantissaBits, int zeroExp)
Converts an 8 bit float to a 32 bit float.
static byte floatToByte(float f, int numMantissaBits, int zeroExp)
Converts a 32 bit float to an 8 bit float.
static byte floatToByte315(float f)
floatToByte(b, mantissaBits=3, zeroExponent=15)
smallest non-zero value = 5.820766E-10
largest value = 7.5161928E9
epsilon = 0.125
static byte floatToByte52(float f)
floatToByte(b, mantissaBits=5, zeroExponent=2)
smallest nonzero value = 0.033203125
largest value = 1984.0
epsilon = 0.03125
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public SmallFloat ()

Public Methods

public static float byte315ToFloat (byte b)

byteToFloat(b, mantissaBits=3, zeroExponent=15)

public static float byte52ToFloat (byte b)

byteToFloat(b, mantissaBits=5, zeroExponent=2)

public static float byteToFloat (byte b, int numMantissaBits, int zeroExp)

Converts an 8 bit float to a 32 bit float.

public static byte floatToByte (float f, int numMantissaBits, int zeroExp)

Converts a 32 bit float to an 8 bit float.
Values less than zero are all mapped to zero.
Values are truncated (rounded down) to the nearest 8 bit value.
Values between zero and the smallest representable value are rounded up.

Parameters
f the 32 bit float to be converted to an 8 bit float (byte)
numMantissaBits the number of mantissa bits to use in the byte, with the remainder to be used in the exponent
zeroExp the zero-point in the range of exponent values
Returns
  • the 8 bit float representation

public static byte floatToByte315 (float f)

floatToByte(b, mantissaBits=3, zeroExponent=15)
smallest non-zero value = 5.820766E-10
largest value = 7.5161928E9
epsilon = 0.125

public static byte floatToByte52 (float f)

floatToByte(b, mantissaBits=5, zeroExponent=2)
smallest nonzero value = 0.033203125
largest value = 1984.0
epsilon = 0.03125