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DC equation coefficients inconsistent or stale?

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randress

DC equation coefficients inconsistent or stale?

I encountered a curious fea.phys.dc.eqn.coef state which I do not recall as causing an error or preventing the generation of a solution, but which may be of interest, especially in light of an earlier post: http://forum.featool.com/Index-exceeds-array-bounds-after-split-object-tp969.html

I have not been able to reproduce this and the file is very large (20Mb). I have placed it at:

http://randress.com/featool/stale_conductivity.fea

... for download if needed.

I exported the fea struct to the MATLAB workspace and found this:

>> print_geom_objects(fea.geom)
*** 4 geom objects ***
 --> Gen 0 (Active Objects)
 1:  'B1', 'block'
           min        max
    x: -60.000000  60.000000
    y: -5.000000   5.000000
    z: -5.000000   5.000000

 2:  'S2', 'sphere'
     center: 50.000000   0.000000   0.000000
     radius:  0.008680
       axis:  1     (1/2/3 ==> x/y/z axis direction)

 3:  'S1', 'sphere'
     center: -50.000000   0.000000   0.000000
     radius:  0.008680
       axis:  1     (1/2/3 ==> x/y/z axis direction)

 4:  'E1', 'ellipsoid'
   center: -49.000000   0.000000   0.000000
    radii:  0.125000   0.175000   0.875000
     axis:  0.000000   0.000000   1.000000

*** end print_geom_objects ***
>> fea.phys.dc.eqn.coef

ans 
  4×4 cell array
    {'dts_dc'}    {'<html><i>d</i><…'}    {'Time scaling co…'}    {1×6 cell}
    {'s_dc'  }    {'<html>&sigma;</…'}    {'Electric conduc…'}    {1×6 cell}
    {'q_dc'  }    {'<html>Q</html>'   }    {'Current source'   }    {1×6 cell}
    {'V0_dc' }    {'<html><font sty…'}    {'Initial conditi…'}    {1×6 cell}

>> fea.phys.dc.eqn.coef{2,:}
ans =
    's_dc'
ans =
    '<html>&sigma;</html>'
ans =
    'Electric conductivity'
ans =
  1×6 cell array
    {'.16'}    {'6e7'}    {'6e7'}    {'.355'}    {'6e7'}    {'.355'}

I have no doubt that earlier this model had 6 subdomains from which the extra sets of elements must have come. I realize that this does not necessarily indicate a bug; stale data that is not referenced would not be a problem but it just seems suspicious.

Please let me know if there is anything additional that I should add.

Kind regards,
Randal

Precise Simulation

Re: DC equation coefficients inconsistent or stale?

Administrator

Yes, if you make a model with several subdomains and later change so that it now has fewer, it might be that the equation and/or boundary coefficients keep the excess entries, but they will not be used or accessed so there should technically be no harm (and if later the model is extended again the "hidden" coefficients will be used as defaults from before).