DOLFIN

Unable to create intersection operator

Asked by Xiaoxian Liu

Hi all,

I was trying to run "d4_p2D.py" without any change in the code. In particular, it compares the solution value at a point that is not a vertex of the given mesh. I copied code for that purpose below:

"...
# Compare numerical and exact solution at the center point
center = (0.5, 0.5)
print 'numerical u at the center point:', u(center)
print 'exact u at the center point:', u0(center)
..."

u0 was the exact solution defined by "Expression()", whereas u was the approximate FEM solution. However, it gave me this error message:

"Error: Unable to create intersection operator.
*** Reason: IntersectionOperatorImplementation is not available, DOLFIN has been compiled without CGAL.
*** Where: This error was encountered inside IntersectionOperator.cpp."

Can anyone help me to solve the problem? Thank you!

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Xiaoxian Liu
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Revision history for this message
Johan Hake (johan-hake) said : 		#1

You need to provide more information about your system. It looks like
you have not compiled dolfin with CGAL.

Johan

On 11/09/2012 05:41 PM, Xiaoxian Liu wrote:
> New question #213771 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/213771
>
> Hi all,
>
> I was trying to run "d4_p2D.py" without any change in the code. In particular, it compares the solution value at a point that is not a vertex of the given mesh. I copied code for that purpose below:
>
> "...
> # Compare numerical and exact solution at the center point
> center = (0.5, 0.5)
> print 'numerical u at the center point:', u(center)
> print 'exact u at the center point:', u0(center)
> ..."
>
> u0 was the exact solution defined by "Expression()", whereas u was the approximate FEM solution. However, it gave me this error message:
>
> "Error: Unable to create intersection operator.
> *** Reason: IntersectionOperatorImplementation is not available, DOLFIN has been compiled without CGAL.
> *** Where: This error was encountered inside IntersectionOperator.cpp."
>
>
> Can anyone help me to solve the problem? Thank you!
>

Revision history for this message
Xiaoxian Liu (liuxiaox) said : 		#2

@Johan: Thank you for the reply. The problem was solved. I added FEniCS following the instruction here:

http://fenicsproject.org/download/ubuntu_details.html#ubuntu-details

There was similar problems on this forum which I should have searched first. Thank you anyway!

Xiaoxian

Revision history for this message
Xiaoxian Liu (liuxiaox) said : 		#3

Sorry I mean I added "FEniCS PPA"~