dolfin team mailing list archive

[Patrick Riesen <priesen@xxxxxxxxxxxxxxx>]

i suppose the problem lies not in VTKFile.cpp.

you consider a tensor function to have a rank >= 2,
but for my tensor function the rank returned by e.g.

e.function_space().element().value_rank()

is 1. So it is rather a vector with 4 components having rank 1.
possibly value_rank() in the FiniteElement class should return 2 even 
for a 2d tensor function, then your code in VTKFile is fine, but i 
didn't look into the FiniteElement classes.

patrick


-------- Original Message --------
Subject: Re: [FEniCS-users] [Fwd: Re:  tensor function]
Date: Wed, 30 Sep 2009 11:30:45 +0200
From: Patrick Riesen <priesen@xxxxxxxxxxxxxxx>
CC: fenics <fenics-users@xxxxxxxxxx>
References: <4AC31DB1.2040001@xxxxxxxxxxxxxxx> 
<4AC320F4.1000600@xxxxxxxxxxxxxxx> <4AC32181.8050202@xxxxxxxxx>

seems that the tensor function for a 2d problem doesn't get to the
output structure for a tensor function but to that for a vector function
because it only has rank = 1. the write out for tensor is only invoked
for a (3x3) tensor with rank = 2.

Garth N. Wells wrote:
> Patrick Riesen wrote:
> > Hello,
> >
> > I don't know if this is a problem (dolfin0.9.2):
> > When i was writing the TensorFunction e to a vtk-file after a solve
> > by just using
> >
> > file << e
> >
> > the results i got were absolutely nonsense. I got three components, 
> > but none of them made any sense. This is why i was thinking i'm doing 
> > something completely wrong in my equations/code,
>
> VTK output of tensor functions is untested. I would be very surprised if 
> it did work. Dig around in VTKFile.cpp to see if you can find the problem.
>
> Garth





> > But if i first separate all components and write them to separate 
> > files as
> >      Function e11 = e[0];
> >      Function e12 = e[1];
> >      Function e21 = e[2];
> >      Function e22 = e[3];
> >
> >      fileE11 << e11;
> >      fileE12 << e12;
> >      fileE21 << e21;
> >      fileE22 << e22;
> >
> > the solutions look reasonable (uff!..) and e12 and e21 are the same.
> >
> > regards,
> > patrick
> >
> >
> > Patrick Riesen wrote:
> > > sorry, something went wrong, this would be the message:
> > >
> > > -------- Original Message --------
> > > Subject: Re: [FEniCS-users] tensor function
> > > Date: Wed, 30 Sep 2009 10:52:02 +0200
> > > From: Patrick Riesen <priesen@xxxxxxxxxxxxxxx>
> > > To: Anders Logg <logg@xxxxxxxxx>
> > > References: <4AC0A8D5.6040207@xxxxxxxxxxxxxxx> 
> > > <20090928122033.GH2528@olorin>    <4AC0AD56.50608@xxxxxxxxxxxxxxx> 
> > > <20090928140134.GA24982@olorin> <4AC0C346.7020309@xxxxxxxxxxxxxxx>
> > >
> > > or maybe not..
> > >
> > > i can not do
> > >
> > > Function e11 = e[0][0];
> > >
> > > i get
> > >
> > > error: no match for 'operator[]' in
> > > 'dolfin::Function::operator[](dolfin::uint)(0u)[0]'
> > >
> > >
> > > but i can get components doing
> > >
> > > e11 = e[0];
> > > e12 = e[1];
> > > e21 = e[2];
> > > e22 = e[3];
> > >
> > >
> > > i suppose for dolfin 0.9.3 it is the case as described below and for
> > > dolfin 0.9.2 the case as above therefore ?
> > > (which is what i am still using currently)
> > >
> > > greetings,
> > > patrick
> > >
> > > Patrick Riesen wrote:
> > > > this helped to sort things out, thanks again.
> > > > patrick
> > > >
> > > > Anders Logg wrote:
> > > > > On Mon, Sep 28, 2009 at 02:34:30PM +0200, Patrick Riesen wrote:
> > > > > > Hi,
> > > > > >
> > > > > > thans for the quick response,
> > > > > >
> > > > > > therefore when V is the function space of the (e, v, p) element and
> > > > > >
> > > > > > > e[0] = (a, b)
> > > > > > > e[1] = (c, d)
> > > > > > > e[0][0] = a
> > > > > > > e[0][1] = b
> > > > > > > e[1][0] = c
> > > > > > > e[1][1] = d
> > > > > > therefore doing
> > > > > >
> > > > > > fs = new SubSpace(V,0,0)
> > > > > >
> > > > > > corresponds to the subspace for the two components (a, b) of the
> > > > > > element  and not just for a, which then would be SubSpace(V,0,0,0) ?
> > > > > Yes.
> > > > >
> > > > > --
> > > > > Anders
> > > > _______________________________________________
> > > > FEniCS-users mailing list
> > > > FEniCS-users@xxxxxxxxxx
> > > > http://fenics.org/mailman/listinfo/fenics-users
> > >
> > > _______________________________________________
> > > FEniCS-users mailing list
> > > FEniCS-users@xxxxxxxxxx
> > > http://fenics.org/mailman/listinfo/fenics-users
> >
> > _______________________________________________
> > FEniCS-users mailing list
> > FEniCS-users@xxxxxxxxxx
> > http://fenics.org/mailman/listinfo/fenics-users

_______________________________________________
FEniCS-users mailing list
FEniCS-users@xxxxxxxxxx
http://fenics.org/mailman/listinfo/fenics-users