Re: [f2py] incompatible parameter transfer between python and fortran?

Hi Xavier,

Your information is very useful, I checked it and it worked, thank you!

Following your arguments, I checked the detailed doc for the generated
module. I seem to reach some very surprising conclusion that the positions
of the variables given in python when calling the module function do not
need to match the variables defined in the fortran subroutines?! For
example, what is defined in fortran as

     subroutine optimize(maxi,n0,inarr0,mu,sig,ret)
      implicit none
      integer,intent(in) :: maxi,n0
      real*8, intent(in) ::  mu,sig,inarr0(n0)
      real*8, intent(out) :: ret(3)

but the optim.optimize.__doc__ gives

optimize - Function signature:
  ret = optimize(maxi,inarr0,mu,sig,[n0])
Required arguments:
  maxi : input int
  inarr0 : input rank-1 array('d') with bounds (n0)
  mu : input float
  sig : input float
Optional arguments:
  n0 := len(inarr0) input int
Return objects:
  ret : rank-1 array('d') with bounds (3)

which means I have to leave n0 at the end of the argument list when calling
optimize from optim module, even n0 is defined on the 2nd place in the
fortran code. I checked the code and it seems my interpretation works.

Please confirm me of this, and please **comment** on how to return several
variables of different types from the fortran code.

Thanks again,

Sincerely,
Jon

On Sun, Oct 31, 2010 at 5:24 PM, Xavier Barthelemy <[email protected]> wrote:

> Hi Jon
>
> I think it's because you are mixing fortran declaration and f2py
> variable declaration.
>
> first you have to tell f2py what you really wants to do:
>
>     subroutine hello(n,m)
>      implicit none
> !f2py integer, intent(in) :: n
> !f2py integer, intent(out) :: m
>       integer n,m
>      print*,'hello world ',n
>      m = n + 5
>      end
>
> and then, the intend(out) has automatically the hidden attribute: That
> means the correct call in python will be
>
> import optim
> n=10
> m=10
> m=optim.hello(n)
>
> you can confirm this with the autodocumentation
> import optim
> print optim.__doc__
>
> hope it helps
> Xavier
>
>
>
> 2010/11/1 Jon <[email protected]>:
> > Hello,
> >
> > I have the following code, compiled by f2py,
> >
> >       subroutine hello(n,m)
> >       implicit none
> > !      integer, intent(in) :: n
> > !      integer, intent(out) :: m
> >       integer n,m
> >       print*,'hello world ',n
> >       m = n + 5
> >       end
> >
> > and called by python code as
> >
> > import optim
> > n=10
> > m=10
> > optim.hello(n,m)
> >
> > The execution result is: the parameter m is not changed, as if only a
> formal
> > parameter is transferred to hello,
> >
> > if I comment out
> >
> > integer n,m
> >
> > and restore the two commented statements,
> >
> >       integer, intent(in) :: n
> >       integer, intent(out) :: m
> >
> > then, python complains
> >
> > TypeError: optim.hello() takes exactly 1 argument (2 given)
> >
> > It seems that f2py does not recognize the intent(out) parameters in the
> > fortran code?!
> >
> > Any idea towards these issues? Thanks a lot!
> >
> > Jon
> >
> >
> > _______________________________________________
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> >
> >
>
>
>
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