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authornobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2014-05-04 01:23:01 (GMT)
committernobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2014-05-04 01:23:01 (GMT)
commit7a6ebecf9ea5d00ccde2d78d45d35aaff3866845 (patch)
treee13381d3405b3685d7f1826debf75fe3106bb855 /math.c
parent6e34259271c705b3d8bb300b5374addb51dce5a0 (diff)
math.c: C99-like atan2
* math.c (math_atan2): return values like as expected by C99 if both two arguments are infinity. based on the patch by cremno phobia <cremno AT mail.ru> in [ruby-core:62310]. [Feature #9799] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45805 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'math.c')
-rw-r--r--math.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/math.c b/math.c
index 70cd26c..b042e7d 100644
--- a/math.c
+++ b/math.c
@@ -55,6 +55,10 @@ VALUE rb_eMathDomainError;
* Math.atan2(1.0, 0.0) #=> 1.5707963267948966
* Math.atan2(1.0, -1.0) #=> 2.356194490192345
* Math.atan2(0.0, -1.0) #=> 3.141592653589793
+ * Math.atan2(INFINITY, INFINITY) #=> 0.7853981633974483
+ * Math.atan2(INFINITY, -INFINITY) #=> 2.356194490192345
+ * Math.atan2(-INFINITY, INFINITY) #=> -0.7853981633974483
+ * Math.atan2(-INFINITY, -INFINITY) #=> -2.356194490192345
*
*/
@@ -75,7 +79,20 @@ math_atan2(VALUE obj, VALUE y, VALUE x)
return DBL2NUM(M_PI);
return DBL2NUM(-M_PI);
}
- if (isinf(dx) && isinf(dy)) domain_error("atan2");
+#if !(defined(HAVE_ATAN2L) && defined(HAVE_ATAN2F)) || 1
+ /* assume atan2() doesn't handle Inf as C99 */
+ if (isinf(dx) && isinf(dy)) {
+ /* optimization for FLONUM */
+ if (dx < 0.0) {
+ const double dz = (3.0 * M_PI / 4.0);
+ return (dy < 0.0) ? DBL2NUM(-dz) : DBL2NUM(dz);
+ }
+ else {
+ const double dz = (M_PI / 4.0);
+ return (dy < 0.0) ? DBL2NUM(-dz) : DBL2NUM(dz);
+ }
+ }
+#endif
return DBL2NUM(atan2(dy, dx));
}