19 August 2018 05:19:09 PM

FEM2D_POISSON_CG:
  C++ version:

  Compiled on Aug 19 2018 at 17:19:08.

  A version of FEM2D_POISSON using sparse storage
  and a conjugate gradient solver.

  Solution of the Poisson equation in an arbitrary region
  in 2 dimensions.

  - DEL H(x,y) DEL U(x,y) + K(x,y) * U(x,y) = F(x,y) in the region

                                     U(x,y) = G(x,y) on the boundary.

  The finite element method is used,
  with triangular elements,
  which must be a 3 node linear triangle.

  Node file is "lake_nodes.txt".
  Element file is "lake_elements.txt".
  Number of nodes =          621

  First 10 nodes

  Row:       1             2       
  Col

    1         316.43       404.476
    2        291.049       400.709
    3        265.165       409.779
    4        241.468       402.403
    5        216.551       396.521
    6        163.285       411.371
    7        142.818       391.164
    8        111.954       346.703
    9        100.035       325.727
   10        103.987       302.516

  Element order =            3
  Number of elements =       973

  First 10 elements

  Row:      1       2       3  
  Col

    1     619     618      39  
    2     620     619      39  
    3     125     126       7  
    4     125     132     126  
    5     143     135     150  
    6     143     150     154  
    7     481      69     482  
    8     454      68     464  
    9     460     472     473  
   10     460     450     472  

  Quadrature order =          3

  Number of nonzero coefficients NZ_NUM = 3809

  Step        Residual

     1         596.276
     2         123.603
     3         26.6837
     4           8.116
     5         2.23573
     6        0.654644
     7        0.205556
     8       0.0591629
     9       0.0186402
    10      0.00584127
    11      0.00194707
    12     0.000627694
    13     0.000195636

  Number of iterations was 13
  Estimated error is 5.46756e-05

  Part of the solution vector vector U:

         1           1.05491
         2          0.981111
         3          0.952925
         4           0.88094
         5          0.816493
         6          0.783552
         7          0.693623
         8          0.530946
         9          0.464421
        10          0.409317

  Wrote an ASCII file
    "lake_values.txt".
  of the form
    U ( X(I), Y(I) )
  which can be used for plotting.

FEM2D_POISSON_CG:
  Normal end of execution.

19 August 2018 05:19:09 PM