gfortran matmul 
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 gfortran matmul

Error in gfortran matmul ?

~$ cat tmatmul.f90
program tmatmul
   implicit none
   integer, parameter         ::  nmax = 3
   integer                    ::  n = 2
   real, dimension(nmax,nmax) ::  B=0.0, C=1.0, X=0.0

   B(1,1) = 1.0
   B(1,2) = 2.0
   B(2,1) = 3.0
   B(2,2) = 5.0

   X(1:n,1) = matmul( B(2,1:n),C(1:n,1:n) )
   print *, X(:,1)
   print *, "  Should be: 8.0  8.0  0.0"

end program tmatmul

~$ ifort-8.1 -o tmatmul-intel81 tmatmul.f90
~$ g95 -o tmatmul-g95 tmatmul.f90
~$ gfortran -o tmatmul-gfortran tmatmul.f90
~$
~$ ./tmatmul-intel81
    8.000000       8.000000      0.0000000E+00
    Should be: 8.0  8.0  0.0
~$
~$ ./tmatmul-g95
  8. 8. 0.
    Should be: 8.0  8.0  0.0
~$
~$ ./tmatmul-gfortran
    3.000000       3.000000       0.000000
    Should be: 8.0  8.0  0.0
~$
~$ gfortran --version
GNU Fortran 95 (GCC) 4.2.0 20060610 (experimental)
....
~$ uname -a
Linux debegil 2.6.15.6 #1 Fri Mar 10 20:51:55 CET 2006 i686 GNU/Linux
also observed in previous versions of gfortran and on x86_64

Regards Egil



Wed, 26 Nov 2008 17:30:44 GMT  
 gfortran matmul

Quote:
> Error in gfortran matmul ?

> ~$ cat tmatmul.f90
> program tmatmul
>    implicit none
>    integer, parameter         ::  nmax = 3
>    integer                    ::  n = 2
>    real, dimension(nmax,nmax) ::  B=0.0, C=1.0, X=0.0

>    B(1,1) = 1.0
>    B(1,2) = 2.0
>    B(2,1) = 3.0
>    B(2,2) = 5.0

>    X(1:n,1) = matmul( B(2,1:n),C(1:n,1:n) )
>    print *, X(:,1)
>    print *, "  Should be: 8.0  8.0  0.0"

> end program tmatmul

> ~$ ifort-8.1 -o tmatmul-intel81 tmatmul.f90
> ~$ g95 -o tmatmul-g95 tmatmul.f90
> ~$ gfortran -o tmatmul-gfortran tmatmul.f90
> ~$
> ~$ ./tmatmul-intel81
>     8.000000       8.000000      0.0000000E+00
>     Should be: 8.0  8.0  0.0
> ~$
> ~$ ./tmatmul-g95
>   8. 8. 0.
>     Should be: 8.0  8.0  0.0
> ~$
> ~$ ./tmatmul-gfortran
>     3.000000       3.000000       0.000000
>     Should be: 8.0  8.0  0.0
> ~$
> ~$ gfortran --version
> GNU Fortran 95 (GCC) 4.2.0 20060610 (experimental)
> ....
> ~$ uname -a
> Linux debegil 2.6.15.6 #1 Fri Mar 10 20:51:55 CET 2006 i686
GNU/Linux
> also observed in previous versions of gfortran and on x86_64

> Regards Egil

I confirm this bug on May 31 windows version of gfortran.

Ian

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Thu, 27 Nov 2008 00:05:45 GMT  
 
 [ 2 post ] 

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