erfd64.3m (2010 09)

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erfd64(3M) erfd64(3M)
(HP Integrity Server Only)
NAME
erfd64(), erfd128(), erfd32(), erfcd64(), erfcd128(), erfcd32() - error functions and complementary error
functions
SYNOPSIS
#define __STDC_WANT_DEC_FP__
#include <math.h>
_Decimal64 erfd64(_Decimal64 x);
_Decimal128 erfd128(_Decimal128 x);
_Decimal32 erfd32(_Decimal32 x);
_Decimal64 erfcd64(_Decimal64 x);
_Decimal128 erfcd128(_Decimal128 x);
_Decimal32 erfcd32(_Decimal32 x);
DESCRIPTION
erfd64() returns the error function of x, defined as:
(2/
sqrt(pi)) * (integral with respect to t from 0 to x of (
exp(pow(-t,2))))
erfcd64() returns the complementary value, 1 −
erfd64(x). It prevents the extreme loss of relative
accuracy if
erfd64(x) is called for a large x and the result is subtracted from 1. (For example, for x=5,
eleven decimal places are lost.)
erfd128() and erfcd128() are _Decimal128 versions of erfd64() and erfcd64(); they take
a _Decimal128 argument and return a _Decimal128 result.
erfd32() and erfcd32() are _Decimal32 versions of erfd64() and erfcd64(); they take a
_Decimal32 argument and return a _Decimal32 result.
These math functions are supported for HP-UX 11i Version 3 September 2008 Update and forward.
USAGE
To use any of these functions, compile with the
+decfp option.
Make sure your program defines
__STDC_WANT_DEC_FP__
and then includes <math.h>.
Link in the math library by specifying
-lm or -l:libm.a on the linking command line.
For more information, see the HP-UX floating-point guide for HP Integrity servers at the following site:
http://www.hp.com/go/fp
.
RETURN VALUE
erfd64(±0) returns ±0.
erfcd64(±0) returns 1.
If x is ±infinity,
erfd64() returns ±1 respectively.
If x is +infinity,
erfc64() returns +0.
If x is −infinity,
erfcd64() returns 2.
If x is NaN, these functions return NaN.
These functions raise the underflow exception whenever a result is tiny (essentially subnormal or zero)
and inexact.
These functions raise the inexact exception whenever a rounded result does not equal the mathematical
result.
ERRORS
No errors are defined.
SEE ALSO
expd64(3M), powd64(3M), sqrtd64(3M), math(5).
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1