ufl team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Kristian Oelgaard wrote:
> Quoting "Garth N. Wells" <gnw20@xxxxxxxxx>:
>
> > I just tested the new FFC generated code (with quadrature) from the UFL
> > input for Poisson. From the input code
> >
> >      element = FiniteElement("Lagrange", "triangle", 1)
> >      v = TestFunction(element)
> >      u = TrialFunction(element)
> >      f = Function(element)
> >
> >      a = dot(grad(v), grad(u))*dx(0, {"quadrature_order":1})
> >      L = v*f*dx(0, {"quadrature_order":2})
> >
> > I computed exactly the same solution as with the FFC .form code, but with
> >
> >      element = FiniteElement("Lagrange", "triangle", 1)
> >      v = TestFunction(element)
> >      u = TrialFunction(element)
> >      f = Function(element)
> >
> >      a = dot(grad(v), grad(u))*dx
> >      L = v*f*dx
> >
> > I see differences. How is the order of integration being selected?
>
> As far as I remember the UFL algorithm currently just looks at order of the
> basis functions:

So it only looks at the test and trial functions, and not the other 
functions? And it doesn't take into account derivatives?

What, if anything, specific will UFL provide to the compiler to help 
decide on the integration order?

Garth


> a: 1*1 = 2
> L: 1   = 1
>
> So the difference is expected.
>
> Kristian
>
>
> > Garth
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