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view build-scripts/mkinstalldirs @ 2752:edd2839b36f7
http://sources.redhat.com/ml/newlib/2002/msg00230.html
Stephen L Moshier wrote:
>
> pow(x,y) returns 0 when x is very close to -1.0 and y is very large.
> The following test program prints
>
> pow(1.0000000000000002e+00 4.5035996273704970e+15) = 2.7182818284590455e+00
> pow(-1.0000000000000002e+00 4.5035996273704970e+15) =0.0000000000000000e+00
> pow(9.9999999999999978e-01 4.5035996273704970e+15) = 3.6787944117144222e-01
> pow(-9.9999999999999978e-01 4.5035996273704970e+15) = 0.0000000000000000e+00
>
> which is incorrect for the negative arguments raised to an odd integer
> power.
>
> -----
> double pow (double, double);
>
> int
> main ()
> {
> double x, y, z;
>
> x = 1.0 + pow (2.0, -52.0);
> y = 1.0 + pow (2.0, 52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = 1.0 - pow (2.0, -52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> }
> -----
>
> Here is a patch for newlib/libm/math/epow.c:
Patch checked in and duplicated for ef_pow.c. Thanks.
-- Jeff J.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 15 Sep 2008 04:31:30 +0000 |
parents | 19418e4422cb |
children |
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#! /bin/sh # mkinstalldirs --- make directory hierarchy # Author: Noah Friedman <friedman@prep.ai.mit.edu> # Created: 1993-05-16 # Public domain errstatus=0 dirmode="" usage="\ Usage: mkinstalldirs [-h] [--help] [-m mode] dir ..." # process command line arguments while test $# -gt 0 ; do case "${1}" in -h | --help | --h* ) # -h for help echo "${usage}" 1>&2; exit 0 ;; -m ) # -m PERM arg shift test $# -eq 0 && { echo "${usage}" 1>&2; exit 1; } dirmode="${1}" shift ;; -- ) shift; break ;; # stop option processing -* ) echo "${usage}" 1>&2; exit 1 ;; # unknown option * ) break ;; # first non-opt arg esac done for file do if test -d "$file"; then shift else break fi done case $# in 0) exit 0 ;; esac case $dirmode in '') if mkdir -p -- . 2>/dev/null; then echo "mkdir -p -- $*" exec mkdir -p -- "$@" fi ;; *) if mkdir -m "$dirmode" -p -- . 2>/dev/null; then echo "mkdir -m $dirmode -p -- $*" exec mkdir -m "$dirmode" -p -- "$@" fi ;; esac for file do set fnord `echo ":$file" | sed -ne 's/^:\//#/;s/^://;s/\// /g;s/^#/\//;p'` shift pathcomp= for d do pathcomp="$pathcomp$d" case "$pathcomp" in -* ) pathcomp=./$pathcomp ;; esac if test ! -d "$pathcomp"; then echo "mkdir $pathcomp" mkdir "$pathcomp" || lasterr=$? if test ! -d "$pathcomp"; then errstatus=$lasterr else if test ! -z "$dirmode"; then echo "chmod $dirmode $pathcomp" lasterr="" chmod "$dirmode" "$pathcomp" || lasterr=$? if test ! -z "$lasterr"; then errstatus=$lasterr fi fi fi fi pathcomp="$pathcomp/" done done exit $errstatus # Local Variables: # mode: shell-script # sh-indentation: 3 # End: # mkinstalldirs ends here