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Computing Eigenvalues

When we feed the so edited inputfile to gd1 (gd1 $<$ wPlunger02.gdf), gd1 gives as final table (on a reasonably fast machine):
 boundary conditions:
 xboundary= electric, electric
 yboundary= electric, electric
 zboundary= electric, electric
 
  --------------------
 
    i   freq(i)       acc(i)         cont(i)
    1  436.4010e+6   1.0044982017  1.0000000000       # "grep" for me
    2  508.3705e+6   0.0014197280  0.0014201239       # "grep" for me
    3  782.2763e+6   0.0000381458  0.0000535041       # "grep" for me
    4  785.5885e+6   0.0002404450  0.0003882672       # "grep" for me
    5    1.0476e+9   0.0000318869  0.0000629098       # "grep" for me
    6    1.0620e+9   0.0002907024  0.0049598724       # "grep" for me
    7    1.0930e+9   0.0002534295  0.0044621769       # "grep" for me
    8    1.0985e+9   0.0001211415  0.0014816978       # "grep" for me
    9    1.1436e+9   0.0003028035  0.0023958708       # "grep" for me
   10    1.2149e+9   0.0040771062  0.0350091443       # "grep" for me
   11    1.2437e+9   0.0074278316  0.1613287149       # "grep" for me
   12    1.2652e+9   0.0671920760  1.0000000000       # "grep" for me
   13    1.2845e+9   0.0265391147  0.5529007301       # "grep" for me
   14    1.3151e+9   0.0376288530  0.3142827624       # "grep" for me
   15    1.3935e+9   0.0930865808  0.8046319226       # "grep" for me
 ################################
 # cpu-seconds for eigenvalues :      472
 # start date                  : 30/11/2002
 # end date                    : 30/11/2002
 # start time                  : 21:41:36
 # end time                    : 21:50:45
 # The computation of the eigenvalues has finished normally..
 # Start the postprocessor to look at the results.
 stop .. normal end ..
The first mode is garbage, as can be seen from its accuracy. But also the other modes are not very good. The reason is: Since we have only a single symmetry plane left (z=0), we have to compute in a volume that is four times as large as the volume before. In such a large volume, there are much more modes than 15 in the frequency range from 0 to estimation (we specified an estimation of 2GHz). We could say that we want to have more solutions, but that would drastically increases our memory consumption. Since we are using already about 200 MBytes (our grid contains 1.2 million gridcells), we do not want to do this. We could try to compute with the single precision version of gd1, single.gd1, then we could compute 30 modes in 200 MByte. Instead we adjust our estimation to 1.2 GHz. The end of our inputfile now is:
 -eigenvalues
    solutions= 15
    estimation= 1.2e9   # the estimated highest frequency
    doit
and the final table of a run (gd1 $<$ wPlunger03.gdf) is
 boundary conditions:
 xboundary= electric, electric
 yboundary= electric, electric
 zboundary= electric, electric
 
  --------------------
 
  The first 2 solutions seem to be static and are not saved.
    i   freq(i)       acc(i)         cont(i)
    1  508.3705e+6   0.0000027120  0.0000022258       # "grep" for me
    2  782.2764e+6   0.0000000527  0.0000000740       # "grep" for me
    3  785.5885e+6   0.0000000113  0.0000000182       # "grep" for me
    4    1.0476e+9   0.0000000021  0.0000000042       # "grep" for me
    5    1.0620e+9   0.0000000009  0.0000000155       # "grep" for me
    6    1.0930e+9   0.0000000245  0.0000004322       # "grep" for me
    7    1.0985e+9   0.0000000053  0.0000000651       # "grep" for me
    8    1.1436e+9   0.0000000643  0.0000005090       # "grep" for me
    9    1.2149e+9   0.0000675156  0.0005797832       # "grep" for me
   10    1.2434e+9   0.0000015519  0.0000339391       # "grep" for me
   11    1.2587e+9   0.0000055368  0.0001618450       # "grep" for me
   12    1.2801e+9   0.0006670306  0.0200800431       # "grep" for me
   13    1.2994e+9   0.0015633650  0.0522703164       # "grep" for me
 ################################
 # cpu-seconds for eigenvalues :      747
 # start date                  : 30/11/2002
 # end date                    : 30/11/2002
 # start time                  : 21:52:37
 # end time                    : 22:06:21
 # The computation of the eigenvalues has finished normally..
 # Start the postprocessor to look at the results.
 stop .. normal end ..
The garbage mode has disappeared, and the accuracies the modes are very good.
next up previous contents
Next: Using gd1.pp to analyse Up: Analysing the real 3D Previous: Defining Material properties   Contents