diff options
Diffstat (limited to 'contrib/perl5/lib/Math/Trig.pm')
| -rw-r--r-- | contrib/perl5/lib/Math/Trig.pm | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/contrib/perl5/lib/Math/Trig.pm b/contrib/perl5/lib/Math/Trig.pm index 924286d..492706c 100644 --- a/contrib/perl5/lib/Math/Trig.pm +++ b/contrib/perl5/lib/Math/Trig.pm @@ -7,13 +7,12 @@ require Exporter; package Math::Trig; +use 5.005_64; use strict; use Math::Complex qw(:trig); -use vars qw($VERSION $PACKAGE - @ISA - @EXPORT @EXPORT_OK %EXPORT_TAGS); +our($VERSION, $PACKAGE, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS); @ISA = qw(Exporter); @@ -37,8 +36,8 @@ my @rdlcnv = qw(cartesian_to_cylindrical %EXPORT_TAGS = ('radial' => [ @rdlcnv ]); -use constant pi2 => 2 * pi; -use constant pip2 => pi / 2; +sub pi2 () { 2 * pi } # use constant generates warning +sub pip2 () { pi / 2 } # use constant generates warning use constant DR => pi2/360; use constant RD => 360/pi2; use constant DG => 400/360; @@ -133,11 +132,11 @@ Math::Trig - trigonometric functions =head1 SYNOPSIS use Math::Trig; - + $x = tan(0.9); $y = acos(3.7); $z = asin(2.4); - + $halfpi = pi/2; $rad = deg2rad(120); @@ -259,7 +258,7 @@ complex numbers as results because the C<Math::Complex> takes care of details like for example how to display complex numbers. For example: print asin(2), "\n"; - + should produce something like this (take or leave few last decimals): 1.5707963267949-1.31695789692482i @@ -273,10 +272,10 @@ and the imaginary part of approximately C<-1.317>. $radians = deg2rad($degrees); $radians = grad2rad($gradians); - + $degrees = rad2deg($radians); $degrees = grad2deg($gradians); - + $gradians = deg2grad($degrees); $gradians = rad2grad($radians); @@ -409,7 +408,16 @@ To calculate the distance between London (51.3N 0.5W) and Tokyo (35.7N $km = great_circle_distance(@L, @T, 6378); The answer may be off by few percentages because of the irregular -(slightly aspherical) form of the Earth. +(slightly aspherical) form of the Earth. The used formula + + lat0 = 90 degrees - phi0 + lat1 = 90 degrees - phi1 + d = R * arccos(cos(lat0) * cos(lat1) * cos(lon1 - lon01) + + sin(lat0) * sin(lat1)) + +is also somewhat unreliable for small distances (for locations +separated less than about five degrees) because it uses arc cosine +which is rather ill-conditioned for values close to zero. =head1 BUGS @@ -426,7 +434,7 @@ an answer instead of giving a fatal runtime error. =head1 AUTHORS Jarkko Hietaniemi <F<jhi@iki.fi>> and -Raphael Manfredi <F<Raphael_Manfredi@grenoble.hp.com>>. +Raphael Manfredi <F<Raphael_Manfredi@pobox.com>>. =cut |
