[Bug libstdc++/13450] New: std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[Bug libstdc++/13450] New: std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[pkienzle at nist dot gov]

In gcc/libstdc++-v3/std/std_complex.h between revision 1.5 and 1.6, the
definition of pow(cplx,real) was changed from:

  return exp(__y * log(__x));

to:

   if (__x.imag() == _Tp())
      return pow(__x.real(), __y);
 	 
   complex<_Tp> __t = log(__x);
   return polar(exp(__y * __t.real()), __y * __t.imag());

It should be testing for negative numbers as well:

   if (__x.imag() == _Tp() && __x.real() >= _Tp())
      ...


Similarly, pow(real,cplx) should also test for real<0.  

Instead of:

   return __x == _Tp()
      ? _Tp()
      : polar(pow(__x, __y.real()), __y.imag() * log(__x));

use something like:

   if (__x == _Tp()) 
      return _Tp();
   else if (__x > _Tp()) 
      return polar(pow(__x, __y.real()), __y.imag() * log(__x));
   else
      return pow(complex<_Tp>(__x,_Tp()), __y);


The following program demonstrates the problem:

#include <cmath>
#include <iostream>
#include <complex>

using namespace std;

typedef double _Tp;

complex<_Tp> mypow(complex<_Tp> __x, _Tp __y)
{
   if (__x.imag() == _Tp() && __x.real() >= _Tp())
      return pow(__x.real(), __y);
 	 
   complex<_Tp> __t = log(__x);
   return polar(exp(__y * __t.real()), __y * __t.imag());
}

complex<_Tp> mypow(_Tp __x, complex<_Tp> __y)
{
  if (__x == _Tp()) 
    return _Tp();
  else if (__x > _Tp())
    return polar(pow(__x, __y.real()), __y.imag() * log(__x));
  else
    return pow(complex<_Tp>(__x,_Tp()),__y);
}

typedef complex<double> cplx;
void test(double a, double b)
{
  cout << "a=" << a << ", b=" << b << endl;
  cout << "pow(-cplx,cplx)   =" << pow(cplx(a,0),cplx(b,0)) << endl;
  cout << "pow(-real,cplx)   =" << pow(a,cplx(b,0)) << endl;
  cout << "pow(-cplx,real)   =" << pow(cplx(a,0),b) << endl;
  cout << "mypow(-real,cplx) =" << mypow(a,cplx(b,0)) << endl;
  cout << "mypow(-cplx,real) =" << mypow(cplx(a,0),b) << endl;
}

int main(int argc, char *argv[])
{
  test(0,0.5);
  test(-1,0.5);
  test(-3.2,1.4);
  test(3.2,1.4);
  return 0;
}

-- 
           Summary: std::pow(std::complex<double>(-1.,0.),0.5) yields
                    (NaN,0)
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pkienzle at nist dot gov
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[paolo at gcc dot gnu dot org]

------- Additional Comments From paolo at gcc dot gnu dot org  2003-12-19 18:08 -------
Gaby, could you please have a look?
Thanks!

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |gdr at gcc dot gnu dot org
                   |dot org                     |
             Status|UNCONFIRMED                 |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2003-12-20 03:26 -------
Subject: Re:  std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

"paolo at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Gaby, could you please have a look?

Yes.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-01-11 04:42 -------
Subject: Re:  New: std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)


I'm not sure I see precisely what your problem is.  
Can you describe it from the mathematical abstract point of view --
ignoring implementation details?
The branch cut for the first parameter is precisely the negative real
axis. 


-- Gaby



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[paolo at gcc dot gnu dot org]

------- Additional Comments From paolo at gcc dot gnu dot org  2004-01-11 10:07 -------
Hi everyone, hi Gaby. I'm attaching what I get with current mainline and
icc8 on x86. There are some differences:

9,10c9,10
< pow(-real,cplx)   =(nan,nan)
< pow(-cplx,real)   =(nan,0)
---
> pow(-real,cplx)   =(nan,0)
> pow(-cplx,real)   =(6.12303e-17,1)
15,16c15,16
< pow(-real,cplx)   =(nan,nan)
< pow(-cplx,real)   =(nan,0)
---
> pow(-real,cplx)   =(nan,0)
> pow(-cplx,real)   =(-1.57468,-4.84637)

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-01-11 15:16 -------
Subject: Re:  std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

"paolo at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Hi everyone, hi Gaby. I'm attaching what I get with current mainline and
| icc8 on x86. There are some differences:

Thanks.

What I'm asking for is what the actual problem is.  As I understand
it, the branch cut is on the negative real axis.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[paolo at gcc dot gnu dot org]

------- Additional Comments From paolo at gcc dot gnu dot org  2004-01-11 16:41 -------
Well, after some years, my basic understanding of complex analysis is not so
good anymore... branch cuts... discontinuity... many values... Riemann sheets...
What's that? ;)

But, I must say, my friend Maple9.03 gives the same numbers of submitter's mypow,
for the concerned cases, that is (0, 1), (-1.57*, -4.84*)...

So...

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-01-11 18:14 -------
Subject: Re:  std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)


  OK, I see what is going wrong.  But the submitter's patch is not right
either. To properly implement the branch cut, we need to test whether
the imaginary part is a positive or negative zero (on IEEE-754
plateform).  Yes that is a crazy notion -- but we got it.
Therefore we need a primitive that tells the sign of a real number.
I just looked at the GCC built-ins and there does not seem to be one.
You can't just test for > or < 0.  And == 0 tells whether it is zero,
it does not tell whether it is negative or positive zero.
Furthermore, this is a template code, so we need to come up with a
design that scales to templates.  This probably means we ought to
compute the log() unconditionally -- but then, I don't recall why I
made the previous change in the first place. 

-- Gaby
 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[paolo at gcc dot gnu dot org]

------- Additional Comments From paolo at gcc dot gnu dot org  2004-01-11 18:57 -------
>                                but then, I don't recall why I
> made the previous change in the first place. 

;)

2003-05-20  Gabriel Dos Reis <gdr@integrable-solutions.net>

	PR libstdc++/10689
	* include/std/std_complex.h (pow): Tidy.


Paolo.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-01-11 19:38 -------
Subject: Re:  std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

"paolo at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| >                                but then, I don't recall why I
| > made the previous change in the first place. 
| 
| ;)
| 
| 2003-05-20  Gabriel Dos Reis <gdr@integrable-solutions.net>
| 
| 	PR libstdc++/10689
| 	* include/std/std_complex.h (pow): Tidy.
| 

The joy of working in team; at least, one will have its brain in good
shape in order to keep the damaged ones working :-)

Thanks, Paolo.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[pkienzle at nist dot gov]

------- Additional Comments From pkienzle at nist dot gov  2004-01-12 16:06 -------
(In reply to comment #9)
>   OK, I see what is going wrong.  But the submitter's patch is not right
> either. To properly implement the branch cut, we need to test whether
> the imaginary part is a positive or negative zero (on IEEE-754
> plateform).  Yes that is a crazy notion -- but we got it.

For example, the following is calculated by Matlab on IRIX:

  >> (-1+realmin*1i)^0.5
     0.0000 + 1.0000i

  >> (-1-realmin*1i)^0.5
     0.0000 - 1.0000i

> Therefore we need a primitive that tells the sign of a real number.

C99 has signbit and copysign.  I was able to access them as follows:

#include <iostream>
#include <cmath>
int main(int argc, char *argv[])
{
   double x=1.0, y=-1.0, z;

   std::cout << "1.0/HUGE_VAL=" << x/HUGE_VAL << std::endl;
   std::cout << "signbit(1.0/HUGE_VAL)="
           << __gnu_cxx::signbit(x/HUGE_VAL) << std::endl;

   std::cout << "-1.0/HUGE_VAL=" << y/HUGE_VAL << std::endl;
   std::cout << "signbit(-1.0/HUGE_VAL)="
           << __gnu_cxx::signbit(y/HUGE_VAL) << std::endl;

   return 0;
}

[prog]$ ./a.out 
1.0/HUGE_VAL=0
signbit(1.0/HUGE_VAL)=0
-1.0/HUGE_VAL=-0
signbit(-1.0/HUGE_VAL)=-2147483648

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-01-12 20:23 -------
Subject: Re:  std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

"pkienzle at nist dot gov" <gcc-bugzilla@gcc.gnu.org> writes:

| > Therefore we need a primitive that tells the sign of a real number.
| 
| C99 has signbit and copysign.  I was able to access them as follows:

Yes, I know C99 has signbit and copysign, but that helps hardly for
this template code for C++.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4/3.5 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-03-03 02:20 -------
This looks like a regression.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.3.3 3.4.0 3.5.0
      Known to work|                            |3.2.3
            Summary|std::pow(std::complex<double|[3.3/3.4/3.5 Regression]
                   |>(-1.,0.),0.5) yields       |std::pow(std::complex<double
                   |(NaN,0)                     |>(-1.,0.),0.5) yields
                   |                            |(NaN,0)
   Target Milestone|---                         |3.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4/3.5 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-03-10 09:16 -------
Subject: Bug 13450

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	paolo@gcc.gnu.org	2004-03-10 09:16:12

Modified files:
	libstdc++-v3   : ChangeLog 
	libstdc++-v3/include/std: std_complex.h 
Added files:
	libstdc++-v3/testsuite/26_numerics/complex: 13450.cc pow.cc 
	libstdc++-v3/testsuite/26_numerics/cmath: overloads.cc 
Removed files:
	libstdc++-v3/testsuite/26_numerics/complex: pow.C 
	libstdc++-v3/testsuite/26_numerics/cmath: overloads.C 

Log message:
	2004-03-10  Paul Kienzle  <pkienzle@nist.gov>
	Paolo Carlini  <pcarlini@suse.de>
	
	PR libstdc++/13450
	* include/std/std_complex.h (pow(const complex&, const _Tp&),
	pow(const _Tp&, const complex&)): Use cmath pow only when safe.
	* testsuite/26_numerics/complex/13450.cc: New.
	
	* testsuite/26_numerics/cmath/overloads.C: Rename to overloads.cc.
	* testsuite/26_numerics/complex/pow.C: Rename to pow.cc and fix.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/ChangeLog.diff?cvsroot=gcc&r1=1.2392&r2=1.2393
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/include/std/std_complex.h.diff?cvsroot=gcc&r1=1.12&r2=1.13
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/13450.cc.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/pow.cc.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/pow.C.diff?cvsroot=gcc&r1=1.2&r2=NONE
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/cmath/overloads.cc.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/cmath/overloads.C.diff?cvsroot=gcc&r1=1.1&r2=NONE



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[andreas dot meier_ at gmx dot de]

------- Additional Comments From andreas dot meier_ at gmx dot de  2004-03-10 20:47 -------
What to do in the 3.4 branch?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mark at codesourcery dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-03-10 21:16 -------
Apply the same patch to GCC 3.4 if the V3 people believe it to be safe.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[pcarlini at suse dot de]

------- Additional Comments From pcarlini at suse dot de  2004-03-10 22:21 -------
We believe so, but, to be 100% safe, we want to wait another 12 hr or so for a
full set of testresults on various platforms.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3/3.4 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-03-11 18:33 -------
Subject: Bug 13450

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	paolo@gcc.gnu.org	2004-03-11 18:33:36

Modified files:
	libstdc++-v3   : ChangeLog 
	libstdc++-v3/include/std: std_complex.h 
Added files:
	libstdc++-v3/testsuite/26_numerics/complex: 13450.cc pow.cc 
	libstdc++-v3/testsuite/26_numerics/cmath: overloads.cc 
Removed files:
	libstdc++-v3/testsuite/26_numerics/complex: pow.C 
	libstdc++-v3/testsuite/26_numerics/cmath: overloads.C 

Log message:
	2004-03-11  Paul Kienzle  <pkienzle@nist.gov>
	Paolo Carlini  <pcarlini@suse.de>
	
	PR libstdc++/13450
	* include/std/std_complex.h (pow(const complex&, const _Tp&),
	pow(const _Tp&, const complex&)): Use cmath pow only when safe.
	* testsuite/26_numerics/complex/13450.cc: New.
	
	* testsuite/26_numerics/cmath/overloads.C: Rename to overloads.cc.
	* testsuite/26_numerics/complex/pow.C: Rename to pow.cc and fix.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.2224.2.60&r2=1.2224.2.61
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/include/std/std_complex.h.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.11.4.1&r2=1.11.4.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/13450.cc.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/pow.cc.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/complex/pow.C.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.2&r2=NONE
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/cmath/overloads.cc.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/testsuite/26_numerics/cmath/overloads.C.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.1&r2=NONE



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[jlquinn at gcc dot gnu dot org]

------- Additional Comments From jlquinn at gcc dot gnu dot org  2004-04-08 03:15 -------
There's a record of a patch here.  Is it safe to close this bug?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pcarlini at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[andreas dot meier_ at gmx dot de]

------- Additional Comments From andreas dot meier_ at gmx dot de  2004-05-18 05:30 -------
Can this patch go into 3.3.4?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gdr at integrable-solutions
                   |                            |dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.3.4                       |3.3.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-08-08 19:45 -------
Subject: Bug 13450

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	hammer-3_3-branch
Changes by:	paolo@gcc.gnu.org	2004-08-08 19:45:56

Modified files:
	libstdc++-v3   : ChangeLog.hammer 
	libstdc++-v3/include/std: std_complex.h 

Log message:
	2004-08-08  Paul Kienzle  <pkienzle@nist.gov>
	Paolo Carlini  <pcarlini@suse.de>
	
	PR libstdc++/13450
	* include/std/std_complex.h (pow(const complex&, const _Tp&),
	pow(const _Tp&, const complex&)): Use cmath pow only when safe.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/ChangeLog.hammer.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.1.2.36&r2=1.1.2.37
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/include/std/std_complex.h.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.2.34.3&r2=1.2.34.4



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-09-28 13:24 -------
Fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|3.3.5                       |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450

[Bug libstdc++/13450] [3.3 Regression] std::pow(std::complex<double>(-1.,0.),0.5) yields (NaN,0)

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.0.0                       |3.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13450