1 .\" Copyright 2008, Linux Foundation, written by Michael Kerrisk
2 .\" <mtk.manpages@gmail.com>
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13 .\" Since the Linux kernel and libraries are constantly changing, this
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18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
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24 .\" Japanese Version Copyright (c) 2008 Akihiro MOTOKI
25 .\" all rights reserved.
26 .\" Translated 2008-09-15, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
28 .\"WORD: subnormal 非正規化の
30 .TH ERFC 3 2010-09-20 "GNU" "Linux Programmer's Manual"
33 .\"O erfc, erfcf, erfcl \- complementary error function
34 erfc, erfcf, erfcl \- 相補誤差関数
40 .BI "double erfc(double " x );
41 .BI "float erfcf(float " x );
42 .BI "long double erfcl(long double " x );
45 .\"O Link with \fI\-lm\fP.
49 .\"O Feature Test Macro Requirements for glibc (see
50 .\"O .BR feature_test_macros (7)):
52 .RB ( feature_test_macros (7)
59 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE ||
60 _POSIX_C_SOURCE\ >=\ 200112L;
69 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
70 _POSIX_C_SOURCE\ >=\ 200112L;
80 .\"O function returns the complementary error function of
82 .\"O that is, 1.0 \- erf(x).
86 の相補誤差関数、つまり 1.0 \- erf(x) を返す。
89 .\"O On success, these functions return the complementary error function of
91 .\"O a value in the range [0,2].
99 .\"O is a NaN, a NaN is returned.
105 .\"O is +0 or \-0, 1 is returned.
107 が +0 か \-0 の場合、1 が返される。
111 .\"O is positive infinity,
118 .\"O is negative infinity,
123 .\"O If the function result underflows and produces an unrepresentable value,
124 .\"O the return value is 0.0.
125 関数の結果がアンダーフローし、表現できない値となる場合は、
128 .\"O If the function result underflows but produces a representable
129 .\"O (i.e., subnormal) value,
130 .\"O .\" e.g., erfc(27) on x86-32
131 .\"O that value is returned, and
132 .\"O a range error occurs.
134 表現できる値 (つまり非正規化数 (subnormal)) となる場合は、
135 .\" 例えば x86-32 での erfc(27)
136 その値が返され、範囲エラー (range error) が発生する。
140 .\"O .BR math_error (7)
141 .\"O for information on how to determine whether an error has occurred
142 .\"O when calling these functions.
143 これらの関数を呼び出した際にエラーが発生したかの判定方法についての情報は
147 .\"O The following errors can occur:
150 .\"O Range error: result underflow (result is subnormal)
151 範囲エラー: 結果のアンダーフロー (結果が非正規化数)
155 .\"O An underflow floating-point exception
156 .\"O .RB ( FE_UNDERFLOW )
162 .\"O These functions do not set
167 .\" FIXME . Is it intentional that these functions do not set errno?
168 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6785
169 .\"O .SH "CONFORMING TO"
172 .\"O The variant returning
174 .\"O also conforms to
177 版の関数は SVr4, 4.3BSD にも準拠している。
182 .\"O functions are provided to avoid the loss accuracy that
183 .\"O would occur for the calculation 1-erf(x) for large values of
185 .\"O (for which the value of erf(x) approaches 1).
189 が大きな値の場合に (erf(x) の値は 1 に近付いていくことで)
190 1-erf(x) の計算において精度が失われるのを避けるためである。