log1pf4

NAME

log1pf4 - return the base-e (natural) logarithms of one more than float elements

SYNOPSIS

Procedure call syntax:

#include <simdmath.h>

vector float log1pf4(vector float x);

Link with -lsimdmath

Inline call syntax:

#include <simdmath.h>

#include <log1pf4.h>

vector float _log1pf4(vector float x);

Parameters
x	input vector

DESCRIPTION

The log1pf4 function returns a vector of the natural logarithms of (1+x) for the corresponding element of x.

This function returns mathematically accurate values even when the corresponding element of x is near 0 because it uses a different algorithm from the log function in the open interval (-0.5, 0.5). Outside this range the function defaults to the standard log routine.

RETURN VALUE

The function log1pf4 returns a float vector in which each element is defined as:

the natural logarithm of the corresponding element of (1+x), if the element is not 0, or
-HUGE_VALF if the value of the corresponding element of x is 0.
If an element of x is less than 1, the corresponding element of the result is undefined.

ENVIRONMENT

SPU and PPU

CONFORMING TO

SIMD Math library specification for the Cell Broadband Engine™ Architecture.

NOTES

Basis

ISO9899 (C99) log1p functions.