SgFastLog Class Reference

Fast logarithm. More...

#include <SgFastLog.h>

List of all members.

Classes
union	IntFloat
Public Member Functions
	SgFastLog (int mantissaBits)
	~SgFastLog ()
float	Log (float val) const
	Get natural logarithm.
Private Member Functions
	SgFastLog (const SgFastLog &)
	Not implemented.
SgFastLog &	operator= (const SgFastLog &)
	Not implemented.
Private Attributes
const int	m_mantissaBitsDiff
float *	m_lookupTable
Static Private Attributes
static const int	MAX_MANTISSA_BITS = 23

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Detailed Description

Fast logarithm.

Computes a fast single precision logarithm based on a lookup table.

O. Vinyals, G. Friedland, N. Mirghafori: Revisiting a basic function on current CPUs: A fast logarithm implementation with adjustable accuracy. http://www.icsi.berkeley.edu/pubs/techreports/TR-07-002.pdf

The implementation assumes that the platform uses IEEE 754 floats.

Definition at line 19 of file SgFastLog.h.

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Constructor & Destructor Documentation

SgFastLog::SgFastLog

(

int

mantissaBits

)

Definition at line 28 of file SgFastLog.cpp.

References SgFastLog::IntFloat::m_float, SgFastLog::IntFloat::m_int, m_lookupTable, and m_mantissaBitsDiff.

SgFastLog::~SgFastLog

(

)

Definition at line 44 of file SgFastLog.cpp.

References m_lookupTable.

SgFastLog::SgFastLog

(

const SgFastLog &

)

[private]

Not implemented.

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Member Function Documentation

float SgFastLog::Log

(

float

val

)

const

Get natural logarithm.

Definition at line 50 of file SgFastLog.h.

References SgFastLog::IntFloat::m_float, SgFastLog::IntFloat::m_int, m_lookupTable, m_mantissaBitsDiff, and MAX_MANTISSA_BITS.

Referenced by SgUctSearch::Log().

SgFastLog& SgFastLog::operator=

(

const SgFastLog &

)

[private]

Not implemented.

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Member Data Documentation

float* SgFastLog::m_lookupTable [private]

Definition at line 41 of file SgFastLog.h.

Referenced by Log(), SgFastLog(), and ~SgFastLog().

const int SgFastLog::m_mantissaBitsDiff [private]

Definition at line 39 of file SgFastLog.h.

Referenced by Log(), and SgFastLog().

const int SgFastLog::MAX_MANTISSA_BITS = 23 [static, private]

Definition at line 37 of file SgFastLog.h.

Referenced by Log().

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The documentation for this class was generated from the following files:

• SgFastLog.h
• SgFastLog.cpp