On 08/26/2012 12:32 PM, Alec Kalinin wrote:
Hi Robert,
Did you mean "linear_elastic_probes.html" instead of "linear_elastic_tractions.html" example? I found the "linear_elastic_probes.html" very useful example for my purposes to probe a solution in the given (x, y, z) points. Also the documentation "src/sfepy/fem/probes.html" gives all necessary information to help me implement what I want to do. Thank you!
Sorry, I cut&pasted a wrong url, the correct one is [1]. But you found another one that solves the problem.
But, despite this, could you tell me more about low-level way to evaluate a variable in the given (x, y, z) point?
It's exactly how the probes do that: the key function is variable.evaluate_at() [2], where variable is an unknown or parameter variable. It takes just one compulsory parameter - the coordinates of points in which you wish to evaluate the variable. You can get the variables of a problem by problem.get_variables(), where problem is the second argument of the post_process_hook function.
Best regards, r.
[1] http://sfepy.org/doc-devel/primer.html#probing [2] http://sfepy.org/doc-devel/src/sfepy/fem/variables.html, http://sfepy.org/doc-devel/src/sfepy/fem/fields.html
On Sunday, August 26, 2012 12:47:50 AM UTC+4, Robert Cimrman wrote:
Hi Alec,
On 08/25/2012 05:45 PM, Alec Kalinin wrote:
Dear SfePy users,
Is it possible to evaluate a solution not only in the FEM mesh node, but in any arbitrary point in the domain with the given (x, y, z) coordinates?
Yes, it is possible. Either, you could use a probe as described in the Primer [1] - the available probes are described in [2]. Or, you could directly evaluate a variable in given points - this is a bit low-level operation, but I could provide you instructions, if the probes are not enough for you.
Cheers, r.
For example, consider Dirichlet problem for Poisson equation. We apply essential boundary conditions on the surface nodes and after the problem has been solved we have the solution vector, i.e. vector of values in the FEM mesh nodes. But I want to know the solution in point v(x, y, z) that is not FEM mesh node. What is the best way to obtain solution in this point v?
Sincerely, Alec Kalinin
[1] doc-devel/examples/linear_elasticity/linear_elastic_tractions.html [2] http://sfepy.org/doc-devel/src/sfepy/fem/probes.html