Ah, yes, I misinterpreted the e-16 values, of course this is zero. Thank you very much!
Quinta-feira, 16 de Maio de 2013 16:46:56 UTC+1, Robert Cimrman escreveu:
The following works for me:
def Def_Sigma(ts,coors,region=None): x = coors[:,0] y = coors[:,1] #val = x*y val = nm.ones_like(x) return val
Maybe run postproc.py with the "-b" option to see colorbars with data ranges:
sfepy: cell vectors Grad_S at [ 0. 0. 0.] sfepy: range: -8.88e-16 8.88e-16 l2 norm range: 0.00e+00 9.93e-16
The values are machine-precision zeros.
r.
On 05/16/2013 05:00 PM, dj....@gmx.de javascript: wrote:
Assigning values 0 to the variable S in my example leads to a calculation of a gradient of S = 0 everywhere which is correct. But assigning other constant values (like 1) leads to different results for the gradient of S, not 0 although it should also be. Just wondered if it has to do with the evaluating function: gradS = pb.evaluate('ev_grad.i2.Omega(S)', S=vv, mode='el_avg') ?
Thx Djamil
Quinta-feira, 16 de Maio de 2013 12:15:07 UTC+1, dj.a...@gmx.deescreveu:
Thanks Robert! Works fine. :)
Quinta-feira, 16 de Maio de 2013 11:31:26 UTC+1, Robert Cimrman
escreveu:
On 05/16/2013 11:22 AM, dj....@gmx.de wrote:
Dear Robert, you are right, the parameter S is not used in the equations, so I
would
have to define it. I tried it without success. Do you have an example how to define it correctly in the postproc-function? I add the code below which gives the mentioned error (argument S not found). It's using the rectangle_fine_tri.mesh.
It can be easily created in this way:
vv = pb.create_variables('S')['S'] vv.time_update(None, pb.functions) gradS = pb.evaluate('ev_grad.i2.Omega(S)', S=vv, mode='el_avg') out['Grad_S'] = Struct(name='output_S', mode='cell', data=gradS,dofs=None)
The example file works after adding the first two lines into the post_process() function (notice the modification of the third line!).
Cheers, r.
Thanks Djamil
Quarta-feira, 15 de Maio de 2013 21:42:37 UTC+1, Robert Cimrman escreveu:
Hi!
On 05/15/2013 04:46 PM, dj....@gmx.de javascript: wrote: > Dear sfepy group, > > I defined a parameter field S and tried to use a function to assign certain > values to the parameter depending of the coordinates. > Like this (simplified): > > variable_7 = { > 'name' : 'S', > 'kind' : 'parameter field', > 'field' : 'pressure', > 'like' : None, > 'special' : {'setter' : 'Def_Sigma'}, > } > > def Def_Sigma(ts,coors,region=None): > x = coors[:,0] > y = coors[:,1] > val = x*y*10 > return val > > The field is: > > field_1 = { > 'name' : 'pressure', > 'dtype' : nm.float64, > 'shape' : (1,), > 'region' : 'Omega', > 'approx_order' : '1', > } > > When I try to calculate the gradient of the parameter S field in a > post-process-hook I always get an error: > > def post_process(out, pb, state, extend=False): > from sfepy.base.base import Struct > > div = pb.evaluate('ev_grad.i2.Omega(S)',mode='el_avg') > out['Grad_S'] = Struct(name='output_data', mode='cell',
data=div,
> dofs=None) > > return out > > The error is: > Argument S not found.
Is the variable S used in the equations (like, e.g. in [1])? If not, it is not created/set by the solver at all. In that case, you would have to create it manually in the post_process() function.
Anyway, it would help if you send a complete file (preferably using one of the sfepy meshes), so that I could run it.
r.
[1]
http://sfepy.org/doc-devel/examples/thermo_elasticity/thermo_elasticity.html