dolfin team mailing list archive

[Kent-Andre Mardal <kent-and@xxxxxxxxx>]

On to., 2008-08-21 at 17:30 +0200, Evan Lezar wrote:
> Thanks for the speedy replies from all of you.
> 
> Firstly platform information
> 
> I am running ubuntu hardy, gcc version 4.2.3, swig 1.3.33, python 2.5
> with release versions of numpy and scipy.  I am building dolfin
> directly from source with mpi, but have not enabled petsc or any of
> the other optional packages.
> 
> What other information do you require?
> 
> In terms of my specific problem, see the following code snippet:
> 
> from dolfin import *
> import numpy as N
> 
> mesh = UnitSquare(4,4)
> element = FiniteElement("Nedelec", "triangle", 0)
> 
> ### Code to assemble system matrices and solve an eigenvalue problem
> 
> # h_e is an array of coefficients associated with the degrees of
> freedom in the system obtained from the eigenvectors V
> h_e = V[:,sorted_index[first_index]]
> 
> # setup a function to evaluate - the solution of the magnetic field
> field = Function(element, self.mesh, h_e)
>         
> # arbitrary point to evaluate the field
> points = N.array((0.5,0.25))
> # array to store the field value at a point
> H = N.array((0.0,0.0))
>         
> print "pre_eval"
>         
> #evaluate the function
> field.eval(H, points)
>         
> # Ouput the field at the point
> print "H",
> print H
> 
> 
> When I run this code, I get the following output:
> 
> pre_eval
> [labby:25160] *** Process received signal ***
> [labby:25160] Signal: Segmentation fault (11)
> [labby:25160] Signal code: Address not mapped (1)
> [labby:25160] Failing at address: 0xde8f58ec
> [labby:25160] [ 0] [0xb7f81440]
> [labby:25160] [ 1] /usr/bin/python(PyEval_EvalCodeEx+0x6e7)
> [0x80cb0d7]
> [labby:25160] [ 2] /usr/bin/python(PyEval_EvalFrameEx+0x565e)
> [0x80c92de]
> [labby:25160] [ 3] /usr/bin/python(PyEval_EvalCodeEx+0x6e7)
> [0x80cb0d7]
> [labby:25160] [ 4] /usr/bin/python(PyEval_EvalFrameEx+0x565e)
> [0x80c92de]
> [labby:25160] [ 5] /usr/bin/python(PyEval_EvalCodeEx+0x6e7)
> [0x80cb0d7]
> [labby:25160] [ 6] /usr/bin/python(PyEval_EvalCode+0x57) [0x80cb227]
> [labby:25160] [ 7] /usr/bin/python(PyRun_FileExFlags+0xf8) [0x80ea6d8]
> [labby:25160] [ 8] /usr/bin/python(PyRun_SimpleFileExFlags+0x199)
> [0x80ea979]
> [labby:25160] [ 9] /usr/bin/python(Py_Main+0xa35) [0x8059335]
> [labby:25160] [10] /usr/bin/python(main+0x22) [0x80587f2]
> [labby:25160] [11] /lib/tls/i686/cmov/libc.so.6(__libc_start_main
> +0xe0) [0xb7de8450]
> [labby:25160] [12] /usr/bin/python [0x8058761]
> [labby:25160] *** End of error message ***
> 
> With a previous build I have gotten different output and was able to
> actually display the contents of H, but it would shill crash once the
> method where the code was being run was terminated.  I logged a bug
> against it at
> http://www.fenics.org/cgi-bin/bugzilla/show_bug.cgi?id=55 
> 
> As I said in my mail, I see myself using fenics in the long run and
> would like to get involved as much as possible, but some pointers as
> to where to start would be much apprciated.
> 
> Thanks in advance
> Evan
> 

It would be nice with a code that we can actually run. 

You may also want to use a debugger, ddd let you set breakpoints etc
if you run the python shell in a separate execution window (Alt+9). 

Kent