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[Anders Logg <logg@xxxxxxxxx>]

On Sat, Apr 25, 2009 at 11:40:35AM +0200, Martin Sandve Alnæs wrote:
> I've verified the curl vs wikipedia and defined rot as the z-component
> of the curl of the 2D vector operand embedded in 3D. Is that right?
> 
> ez = (0, 0, 1)
> u = (u0, u1)
> rot(u) =  ez . (nabla x (u0, u1, 0))
> 
>     def curl(self, o, a):
>         # o = curl a = "cross(nabla, a)"
>         def c(i, j):
>             return a[j].dx(i) - a[i].dx(j)
>         return as_vector((c(1,2), c(2,0), c(0,1)))
> 
>     def rot(self, o, a):
>         # o = rot a = "cross(nabla, (a0, a1, 0))[2]"
>         def c(i, j):
>             return a[j].dx(i) - a[i].dx(j)
>         return c(0,1)
> 
> Martin

It looks correct, but shouldn't there be some dimension check?

Maybe rot can be implemented directly as

     def rot(self, o, a):
         return curl(as_vector([a[0], a[1], 0]))[2]

?

-- 
Anders

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