SmallFloat (Lucene 2.4.1 API)
Keywords: org.apache.lucene.util.SmallFloat class

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## org.apache.lucene.util
Class SmallFloat

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

    public class SmallFloat

extends Object

Floating point numbers smaller than 32 bits.

Version:
  $Id$

Constructor Summary
`SmallFloat()`

Method Summary
`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

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### SmallFloat

    public SmallFloat()

Method Detail

### floatToByte

    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

### byteToFloat

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

  Converts an 8 bit float to a 32 bit float.

### floatToByte315

    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

### byte315ToFloat

    public static float byte315ToFloat(byte b)

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

### floatToByte52

    public static byte floatToByte52(float f)

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

### byte52ToFloat

    public static float byte52ToFloat(byte b)

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

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