[Rd] Problem with function in fortran 95

Göran Broström gb at stat.umu.se
Wed Aug 12 16:59:52 CEST 2009


Fabio Mathias Corrêa skrev:
> I am writing a function in fortran 95, but the intrinsic function MATMUL is not working properly. Here's an example.
> 
> 	SUBROUTINE mymult(x,y,res,m,n)
>         IMPLICIT NONE
>         INTEGER :: m,n
> 	REAL :: x, y, res

Is REAL in Fortran 95 the same as "double precision" in Fortran 77? It 
should be for this to work.

Göran

>         DIMENSION :: x(m,n), y(n,m), res(m,m)
>         res = MATMUL(x,y)
>         END SUBROUTINE mymult
> 
> R CMD SHLIB mat.f95
> 
> In R:
> 
> dyn.load("mat.so")
> x   <- matrix(1:20,5)
> l   <- nrow(x)
> c   <- ncol(x)
> y   <- matrix(20:1,c)
> res <- matrix(0,l,l)
> dim(x)
> dim(y)
> dim(res)
> l
> c
> .Fortran("mymult", x,y,res,l,c)
> 
> [[1]]
>      [,1] [,2] [,3] [,4]
> [1,]    1    6   11   16
> [2,]    2    7   12   17
> [3,]    3    8   13   18
> [4,]    4    9   14   19
> [5,]    5   10   15   20
> 
> [[2]]
>      [,1] [,2] [,3] [,4] [,5]
> [1,]   20   16   12    8    4
> [2,]   19   15   11    7    3
> [3,]   18   14   10    6    2
> [4,]   17   13    9    5    1
> 
> [[3]]
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    0    0    0    0    0
> [2,]    0    0    0    0    0
> [3,]    0    0    0    0    0
> [4,]    0    0    0    0    0
> [5,]    0    0    0    0    0
> 
> [[4]]
> [1] 5
> 
> [[5]]
> [1] 4
> 
> 
> Linux Ubuntu 8.04 and use compiler gfortran 4.2.
> The problem is the compiler?
> 
> Thanks!
> 
>                Fábio Mathias Corrêa
> Estatística e Experimentação Agropecuária/UFLA
>                       Brazil
> 
> 
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