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author | 2003-06-02 10:42:43 +0000 | |
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committer | 2003-06-02 10:42:43 +0000 | |
commit | 9eb52f1ba6df13cf97931ba8546fa1841f647147 (patch) | |
tree | 5dd43b50d2050fd6f9e92e22d078a977cab72536 /lib/libm/man/exp.3 | |
parent | section reorder; (diff) | |
download | wireguard-openbsd-9eb52f1ba6df13cf97931ba8546fa1841f647147.tar.xz wireguard-openbsd-9eb52f1ba6df13cf97931ba8546fa1841f647147.zip |
section reorder;
Diffstat (limited to 'lib/libm/man/exp.3')
-rw-r--r-- | lib/libm/man/exp.3 | 92 |
1 files changed, 46 insertions, 46 deletions
diff --git a/lib/libm/man/exp.3 b/lib/libm/man/exp.3 index 025f30b3e4d..a136d4d98b8 100644 --- a/lib/libm/man/exp.3 +++ b/lib/libm/man/exp.3 @@ -1,4 +1,4 @@ -.\" $OpenBSD: exp.3,v 1.14 2003/05/20 09:17:51 jmc Exp $ +.\" $OpenBSD: exp.3,v 1.15 2003/06/02 10:42:43 jmc Exp $ .\" .\" Copyright (c) 1985, 1991 Regents of the University of California. .\" All rights reserved. @@ -134,51 +134,6 @@ The .Fn powf function is a single precision version of .Fn pow . -.Sh ERRORS (due to Roundoff etc.) -exp(x), log(x), expm1(x) and log1p(x) are accurate to within -an -.Em ulp , -and log10(x) to within about 2 -.Em ulps ; -an -.Em ulp -is one -.Em Unit -in the -.Em Last -.Em Place . -The error in -.Fn pow x y -is below about 2 -.Em ulps -when its -magnitude is moderate, but increases as -.Fn pow x y -approaches -the over/underflow thresholds until almost as many bits could be -lost as are occupied by the floating\-point format's exponent -field; that is 8 bits for -.Tn "VAX D" -and 11 bits for IEEE 754 Double. -No such drastic loss has been exposed by testing; the worst -errors observed have been below 20 -.Em ulps -for -.Tn "VAX D" , -300 -.Em ulps -for -.Tn IEEE -754 Double. -Moderate values of -.Fn pow -are accurate enough that -.Fn pow integer integer -is exact until it is bigger than 2**56 on a -.Tn VAX , -2**53 for -.Tn IEEE -754. .Sh RETURN VALUES These functions will return the appropriate computation unless an error occurs or an argument is out of range. @@ -227,6 +182,51 @@ by log unless unless .Fa x > \-1. +.Sh ERRORS (due to Roundoff etc.) +exp(x), log(x), expm1(x) and log1p(x) are accurate to within +an +.Em ulp , +and log10(x) to within about 2 +.Em ulps ; +an +.Em ulp +is one +.Em Unit +in the +.Em Last +.Em Place . +The error in +.Fn pow x y +is below about 2 +.Em ulps +when its +magnitude is moderate, but increases as +.Fn pow x y +approaches +the over/underflow thresholds until almost as many bits could be +lost as are occupied by the floating\-point format's exponent +field; that is 8 bits for +.Tn "VAX D" +and 11 bits for IEEE 754 Double. +No such drastic loss has been exposed by testing; the worst +errors observed have been below 20 +.Em ulps +for +.Tn "VAX D" , +300 +.Em ulps +for +.Tn IEEE +754 Double. +Moderate values of +.Fn pow +are accurate enough that +.Fn pow integer integer +is exact until it is bigger than 2**56 on a +.Tn VAX , +2**53 for +.Tn IEEE +754. .Sh NOTES The functions exp(x)\-1 and log(1+x) are called expm1 and logp1 in |