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man:erfc

ERFC(3) Linux Programmer's Manual ERFC(3)

NAME

     erfc, erfcf, erfcl - complementary error function

SYNOPSIS

     #include <math.h>
     double erfc(double x);
     float erfcf(float x);
     long double erfcl(long double x);
     Link with -lm.
 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
     erfc():
         _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE
             || /* Since glibc 2.19: */ _DEFAULT_SOURCE
             || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
     erfcf(), erfcl():
         _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
             || /* Since glibc 2.19: */ _DEFAULT_SOURCE
             || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

     These  functions return the complementary error function of x, that is,
     1.0 - erf(x).

RETURN VALUE

     On success, these functions return the complementary error function  of
     x, a value in the range [0,2].
     If x is a NaN, a NaN is returned.
     If x is +0 or -0, 1 is returned.
     If x is positive infinity, +0 is returned.
     If x is negative infinity, +2 is returned.
     If  the  function  result  underflows  and  produces an unrepresentable
     value, the return value is 0.0.
     If the function result underflows but produces a  representable  (i.e.,
     subnormal) value, that value is returned, and a range error occurs.

ERRORS

     See  math_error(7) for information on how to determine whether an error
     has occurred when calling these functions.
     The following errors can occur:
     Range error: result underflow (result is subnormal)
            An underflow floating-point exception (FE_UNDERFLOW) is  raised.
     These functions do not set errno.

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).
     +-------------------------+---------------+---------+
     |Interface                | Attribute     | Value   |
     +-------------------------+---------------+---------+
     |erfc(), erfcf(), erfcl() | Thread safety | MT-Safe |
     +-------------------------+---------------+---------+

CONFORMING TO

     C99, POSIX.1-2001, POSIX.1-2008.
     The variant returning double also conforms to SVr4, 4.3BSD.

NOTES

     The  erfc(),  erfcf(),  and erfcl() functions are provided to avoid the
     loss accuracy that would occur for the calculation 1-erf(x)  for  large
     values of x (for which the value of erf(x) approaches 1).

SEE ALSO

     cerf(3), erf(3), exp(3)

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 ERFC(3)

/data/webs/external/dokuwiki/data/pages/man/erfc.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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