From: Jarkko Hietaniemi <jhi@iki.fi>
Date: Fri, 25 Aug 2000 23:54:34 +0000 (+0000)
Subject: Support preserving extremely big/small angles.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=9db5a202456c4160bf9108553745252960c7c050;p=p5sagit%2Fp5-mst-13.2.git

Support preserving extremely big/small angles.

p4raw-id: //depot/perl@6827
---

diff --git a/lib/Math/Trig.pm b/lib/Math/Trig.pm
index 492706c..b28f150 100644
--- a/lib/Math/Trig.pm
+++ b/lib/Math/Trig.pm
@@ -36,14 +36,15 @@ my @rdlcnv = qw(cartesian_to_cylindrical
 
 %EXPORT_TAGS = ('radial' => [ @rdlcnv ]);
 
-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;
-use constant GD   => 360/400;
-use constant RG   => 400/pi2;
-use constant GR   => pi2/400;
+sub pi2  () { 2 * pi }
+sub pip2 () { pi / 2 }
+
+sub DR  () { pi2/360 }
+sub RD  () { 360/pi2 }
+sub DG  () { 400/360 }
+sub GD  () { 360/400 }
+sub RG  () { 400/pi2 }
+sub GR  () { pi2/400 }
 
 #
 # Truncating remainder.
@@ -58,17 +59,23 @@ sub remt ($$) {
 # Angle conversions.
 #
 
-sub rad2deg ($)  { remt(RD * $_[0], 360) }
+sub rad2rad($)     { remt($_[0], pi2) }
+
+sub deg2deg($)     { remt($_[0], 360) }
+
+sub grad2grad($)   { remt($_[0], 400) }
 
-sub deg2rad ($)  { remt(DR * $_[0], pi2) }
+sub rad2deg ($;$)  { my $d = RD * $_[0]; $_[1] ? $d : deg2deg($d) }
 
-sub grad2deg ($) { remt(GD * $_[0], 360) }
+sub deg2rad ($;$)  { my $d = DR * $_[0]; $_[1] ? $d : rad2rad($d) }
 
-sub deg2grad ($) { remt(DG * $_[0], 400) }
+sub grad2deg ($;$) { my $d = GD * $_[0]; $_[1] ? $d : deg2deg($d) }
 
-sub rad2grad ($) { remt(RG * $_[0], 400) }
+sub deg2grad ($;$) { my $d = DG * $_[0]; $_[1] ? $d : grad2grad($d) }
 
-sub grad2rad ($) { remt(GR * $_[0], pi2) }
+sub rad2grad ($;$) { my $d = RG * $_[0]; $_[1] ? $d : grad2grad($d) }
+
+sub grad2rad ($;$) { my $d = GR * $_[0]; $_[1] ? $d : rad2rad($d) }
 
 sub cartesian_to_spherical {
     my ( $x, $y, $z ) = @_;
@@ -280,6 +287,14 @@ and the imaginary part of approximately C<-1.317>.
 	$gradians = rad2grad($radians);
 
 The full circle is 2 I<pi> radians or I<360> degrees or I<400> gradians.
+The result is by default wrapped to be inside the [0, {2pi,360,400}[ circle.
+If you don't want this, supply a true second argument:
+
+	$zillions_of_radians  = deg2rad($zillions_of_degrees, 1);
+	$negative_degrees     = rad2deg($negative_radians, 1);
+
+You can also do the wrapping explicitly by rad2rad(), deg2deg(), and
+grad2grad().
 
 =head1 RADIAL COORDINATE CONVERSIONS
 
diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index c496caf..e1d7b18 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -155,8 +155,9 @@ the podlators bundle, Pod::LaTeX, Pod::Parser, Term::ANSIColor, Test.
 =item *
 
 Bug fixes and minor enhancements have been applied to B::Deparse,
-Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat, Math::Complex,
-re, SelfLoader, Sys::SysLog, Test::Harness, Text::Wrap, UNIVERSAL.
+Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat,
+Math::Complex, Math::Trig, re, SelfLoader, Sys::SysLog, Test::Harness,
+Text::Wrap, UNIVERSAL.
 
 =item *
 
diff --git a/t/lib/trig.t b/t/lib/trig.t
index 20669f0..b68eb02 100755
--- a/t/lib/trig.t
+++ b/t/lib/trig.t
@@ -29,7 +29,7 @@ sub near ($$;$) {
     abs($_[0] - $_[1]) < (defined $_[2] ? $_[2] : $eps);
 }
 
-print "1..20\n";
+print "1..23\n";
 
 $x = 0.9;
 print 'not ' unless (near(tan($x), sin($x) / cos($x)));
@@ -137,24 +137,44 @@ use Math::Trig ':radial';
 }
 
 {
-        use Math::Trig 'great_circle_distance';
+    use Math::Trig 'great_circle_distance';
 
-	print 'not '
-	    unless (near(great_circle_distance(0, 0, 0, pi/2), pi/2));
-	print "ok 18\n";
+    print 'not '
+	unless (near(great_circle_distance(0, 0, 0, pi/2), pi/2));
+    print "ok 18\n";
 
-	print 'not '
-	    unless (near(great_circle_distance(0, 0, pi, pi), pi));
-	print "ok 19\n";
+    print 'not '
+	unless (near(great_circle_distance(0, 0, pi, pi), pi));
+    print "ok 19\n";
 
-	# London to Tokyo.
-	my @L = (deg2rad(-0.5), deg2rad(90 - 51.3));
-        my @T = (deg2rad(139.8),deg2rad(90 - 35.7));
+    # London to Tokyo.
+    my @L = (deg2rad(-0.5), deg2rad(90 - 51.3));
+    my @T = (deg2rad(139.8),deg2rad(90 - 35.7));
 
-	my $km = great_circle_distance(@L, @T, 6378);
+    my $km = great_circle_distance(@L, @T, 6378);
 
-        print 'not ' unless (near($km, 9605.26637021388));
-	print "ok 20\n";
+    print 'not ' unless (near($km, 9605.26637021388));
+    print "ok 20\n";
+}
+
+{
+    my $lotta_radians = deg2rad(1E+20, 1);
+    print "not " unless near($lotta_radians,  1E+20/57.29577951308232087721);
+    print "ok 21\n";
+
+    my $negat_degrees = rad2deg(-1E20, 1);
+    print "not " unless near($negat_degrees, -1E+20*57.29577951308232087721);
+    print "ok 22\n";
+
+    my $posit_degrees = rad2deg(-10000, 1);
+    print "not " unless near($posit_degrees, -10000*57.29577951308232087721);
+
+    print "ok 23\n";
+
+    my $posiu_degrees = rad2deg(-10000, 0);
+    print "not " unless near($posiu_degrees, -197.795130823273);
+
+    print "ok 24\n";
 }
 
 # eof