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math.c: C99-like atan2

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* 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
This commit is contained in:
nobu 2014-05-04 01:23:01 +00:00
parent 6e34259271
commit 7a6ebecf9e
5 changed files with 36 additions and 5 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
Sun May 4 10:22:59 2014 Nobuyoshi Nakada <nobu@ruby-lang.org>
* 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]
Sun May 4 03:46:42 2014 Tanaka Akira <akr@fsij.org> Sun May 4 03:46:42 2014 Tanaka Akira <akr@fsij.org>
* lib/time.rb (Time.httpdate): Always return a UTC Time object. * lib/time.rb (Time.httpdate): Always return a UTC Time object.

2
NEWS
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@ -54,6 +54,8 @@ with all sufficient information, see the ChangeLog file.
* Math.log now raises Math::DomainError instead of returning NaN if the * Math.log now raises Math::DomainError instead of returning NaN if the
base is less than 0, and returns NaN instead of -infinity if both of base is less than 0, and returns NaN instead of -infinity if both of
two arguments are 0. two arguments are 0.
* Math.atan2 now returns values like as expected by C99 if both two
arguments are infinity.
* Proc * Proc
* incompatible changes: * incompatible changes:

1
configure.in
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@ -1941,6 +1941,7 @@ AC_CHECK_FUNCS(__syscall)
AC_CHECK_FUNCS(_longjmp) # used for AC_ARG_WITH(setjmp-type) AC_CHECK_FUNCS(_longjmp) # used for AC_ARG_WITH(setjmp-type)
AC_CHECK_FUNCS(_setjmp) # used for AC_ARG_WITH(setjmp-type) AC_CHECK_FUNCS(_setjmp) # used for AC_ARG_WITH(setjmp-type)
AC_CHECK_FUNCS(_setjmpex) # used for AC_ARG_WITH(setjmp-type) AC_CHECK_FUNCS(_setjmpex) # used for AC_ARG_WITH(setjmp-type)
AC_CHECK_FUNCS(atan2l atan2f)
AC_CHECK_FUNCS(chroot) AC_CHECK_FUNCS(chroot)
AC_CHECK_FUNCS(chsize) AC_CHECK_FUNCS(chsize)
AC_CHECK_FUNCS(clock_gettime) AC_CHECK_FUNCS(clock_gettime)

19
math.c
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@ -55,6 +55,10 @@ VALUE rb_eMathDomainError;
* Math.atan2(1.0, 0.0) #=> 1.5707963267948966 * Math.atan2(1.0, 0.0) #=> 1.5707963267948966
* Math.atan2(1.0, -1.0) #=> 2.356194490192345 * Math.atan2(1.0, -1.0) #=> 2.356194490192345
* Math.atan2(0.0, -1.0) #=> 3.141592653589793 * 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);
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)); return DBL2NUM(atan2(dy, dx));
} }

13
test/ruby/test_math.rb
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@ -22,10 +22,15 @@ class TestMath < Test::Unit::TestCase
check(-0.0, Math.atan2(-0.0, +0.0)) check(-0.0, Math.atan2(-0.0, +0.0))
check(+Math::PI, Math.atan2(+0.0, -0.0)) check(+Math::PI, Math.atan2(+0.0, -0.0))
check(-Math::PI, Math.atan2(-0.0, -0.0)) check(-Math::PI, Math.atan2(-0.0, -0.0))
assert_raise(Math::DomainError) { Math.atan2(Float::INFINITY, Float::INFINITY) }
assert_raise(Math::DomainError) { Math.atan2(Float::INFINITY, -Float::INFINITY) } inf = Float::INFINITY
assert_raise(Math::DomainError) { Math.atan2(-Float::INFINITY, Float::INFINITY) } expected = 3.0 * Math::PI / 4.0
assert_raise(Math::DomainError) { Math.atan2(-Float::INFINITY, -Float::INFINITY) } assert_nothing_raised { check(+expected, Math.atan2(+inf, -inf)) }
assert_nothing_raised { check(-expected, Math.atan2(-inf, -inf)) }
expected = Math::PI / 4.0
assert_nothing_raised { check(+expected, Math.atan2(+inf, +inf)) }
assert_nothing_raised { check(-expected, Math.atan2(-inf, +inf)) }
check(0, Math.atan2(0, 1)) check(0, Math.atan2(0, 1))
check(Math::PI / 4, Math.atan2(1, 1)) check(Math::PI / 4, Math.atan2(1, 1))
check(Math::PI / 2, Math.atan2(1, 0)) check(Math::PI / 2, Math.atan2(1, 0))