dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

On Sunday 07 March 2010 12:51:20 Garth N. Wells wrote:
> Johan Hake wrote:
> > On Sunday 07 March 2010 06:07:58 Garth N. Wells wrote:
> >> Anders Logg wrote:
> >>> On Sun, Mar 07, 2010 at 12:11:53PM +0000, Garth N. Wells wrote:
> >>>> I've added the function
> >>>>
> >>>>   GenericVector::sum(const std::vector<uint>& rows)
> >>>>
> >>>> which will sum the given row entries. But, frustratingly, it doesn't
> >>>> work through Python. I can't pass a list or numpy array to it. I get
> >>>> the error
> >>>>
> >>>> TypeError: in method 'GenericVector_sum', argument 2 of type
> >>>> 'std::vector< dolfin::uint > const &'
> >>>>
> >>>> How can I pass a list of integers to this function from Python? It
> >>>> seems that we haven't resolved passing std::vector from Python to C++
> >>>> satisfactorily.
> >>>>
> >>>> Garth
> >>>
> >>> Why std::vector? I thought we discussed replacing it with
> >>> dolfin::Array in the interface so that it would map easily to Python
> >>> which would let us remove the std::vector typemaps.
> >>
> >> dolfin::Array doesn't work either.
> >
> > This is because these typemaps needed to be instantiated per argument
> > name. I have now added "greedy" (argument independent) typemaps for all
> >
> >    const Array<{uint,int,double}> & foo
> >
> > arguments, using the typemap macro. I guess _all_ const Array argument of
> > the above primitive types can safely be passed using NumPy arrays. It
> > should now just work for all argument names of the above types.
> >
> > We still cannot do this for all Array arguments, as some might be turned
> > into an argout typemap, which needs to be treated independently. But
> > again I do not have the whole overview of these cases (if any).
> >
> > It should now be possible to change all const
> > std::vector<{uint,int,double}>& foo to Array, and the above mentioned
> > typemap should kick in.
> 
> Can you give an example of how it should work? I've tried
> 
>   tmp0 = numpy.array( [0, 1, 2], dtype=numpy.uint32)
>   tmp1 = numpy.array( [0, 1, 2])
>   tmp2 = [0, 1, 2]
>   sum  = u.vector().sum(tmp0)
> 
> (with tmp0, tmp1 and tmp2), but in all cases I get:
> 
> TypeError: in method 'GenericVector_sum', argument 2 of type
> 'dolfin::Array< dolfin::uint > const &'

Have you tried dtype="I"?

It work for me.

Johan