[Bug fortran/36305] New: real and imaginary part of complex exponential

[Bug fortran/36305] New: real and imaginary part of complex exponential

[rbustos76 at yahoo dot com dot ar]

the following program does not work properly. The value of "y2" should be equal
to the value of "y2". The real and the imaginary part of y2 are inverted!!!

        program riemann
        implicit none
        complex (KIND=8) y,y2,imag
        real (KIND=8) theta,dtheta,thetamax,Pi
        integer i,Ntheta
C******************************
        imag=cmplx(0.0d0,1.0d0)
        Pi=dacos(-1.d0)
        Ntheta=100
        thetamax=2.0d0*Pi
        dtheta=thetamax/real(Ntheta)
        do i=1,Ntheta
        theta=i*dtheta
        y=cdexp(imag*theta)**0.5
        y2=cdexp(imag*theta/2.0d0)
C******************************************
        write(10,1000)real(y),aimag(y)
     &,real(y2),aimag(y2)
        end do
        stop
1000    format(10E16.8)
        end program


-- 
           Summary: real and imaginary part of complex exponential
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rbustos76 at yahoo dot com dot ar


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36305

[Bug fortran/36305] real and imaginary part of complex exponential

[kargl at gcc dot gnu dot org]

------- Comment #1 from kargl at gcc dot gnu dot org  2008-05-23 03:02 -------
Upgrade your compiler.  4.1.2 is extremely old, and the 4.1.x branch
is no longer maintained.  With 4.2.3, the first four values are

  0.99950656E+00  0.31410759E-01  0.99950656E+00  0.31410759E-01
  0.99802673E+00  0.62790520E-01  0.99802673E+00  0.62790520E-01
  0.99556196E+00  0.94108313E-01  0.99556196E+00  0.94108313E-01
  0.99211470E+00  0.12533323E+00  0.99211470E+00  0.12533323E+00

With 4.4.0, the first four values are

  0.99950656E+00  0.31410759E-01  0.99950656E+00  0.31410759E-01
  0.99802673E+00  0.62790520E-01  0.99802673E+00  0.62790520E-01
  0.99556196E+00  0.94108313E-01  0.99556196E+00  0.94108313E-01
  0.99211470E+00  0.12533323E+00  0.99211470E+00  0.12533323E+00

This PR should be closed with a WONTFIX.


-- 

kargl at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|major                       |normal
      Known to work|                            |4.2.3 4.4.0
           Priority|P3                          |P4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36305

[Bug fortran/36305] real and imaginary part of complex exponential

[tkoenig at gcc dot gnu dot org]

------- Comment #2 from tkoenig at gcc dot gnu dot org  2008-05-25 20:08 -------
This works for me down to 4.1.3:

$ gfortran-4.1 -static foo.f
$ ./a.out
$ head -4 fort.10
  0.99950656E+00  0.31410759E-01  0.99950656E+00  0.31410759E-01
  0.99802673E+00  0.62790520E-01  0.99802673E+00  0.62790520E-01
  0.99556196E+00  0.94108313E-01  0.99556196E+00  0.94108313E-01
  0.99211470E+00  0.12533323E+00  0.99211470E+00  0.12533323E+00
$ gfortran-4.1 -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--with-gxx-include-dir=/usr/include/c++/4.1.3 --program-suffix=-4.1
--enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug
--enable-mpfr --enable-checking=release i486-linux-gnu
Thread model: posix
gcc version 4.1.3 20080114 (prerelease) (Debian 4.1.2-19)

This must have been fixed a long time ago.

I'd like to echo Steve's advice: You should upgrade to 4.3.0 at least,
or wait another week for the 4.3.1 release.


-- 

tkoenig at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
      Known to work|4.2.3 4.4.0                 |4.2.3 4.4.0 4.1.2
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36305