19 August 2018 05:19:10 PM FEM2D_POISSON_SPARSE: C++ version: Compiled on Aug 19 2018 at 17:19:10. A finite element method solver for the Poisson problem in an arbitrary triangulated region in 2 dimensions, using sparse storage and an iterative solver. - 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 ITR = 1 Residual = 7759.26 K = 1 Residual = 4032.12 K = 2 Residual = 2064.15 K = 3 Residual = 1043.02 K = 4 Residual = 590.701 K = 5 Residual = 322.888 K = 6 Residual = 216.479 K = 7 Residual = 135.269 K = 8 Residual = 86.7756 K = 9 Residual = 60.0495 K = 10 Residual = 41.0706 K = 11 Residual = 29.9242 K = 12 Residual = 24.3014 K = 13 Residual = 21.8875 K = 14 Residual = 20.799 K = 15 Residual = 20.2832 K = 16 Residual = 20.0608 K = 17 Residual = 19.8118 K = 18 Residual = 19.4362 K = 19 Residual = 18.4348 K = 20 Residual = 16.6214 ITR = 2 Residual = 16.6214 K = 1 Residual = 15.4254 K = 2 Residual = 14.6186 K = 3 Residual = 14.2974 K = 4 Residual = 14.0434 K = 5 Residual = 13.8703 K = 6 Residual = 13.6962 K = 7 Residual = 13.5309 K = 8 Residual = 13.0732 K = 9 Residual = 12.0107 K = 10 Residual = 10.759 K = 11 Residual = 9.32398 K = 12 Residual = 7.74327 K = 13 Residual = 5.52235 K = 14 Residual = 3.19957 K = 15 Residual = 1.89204 K = 16 Residual = 1.20179 K = 17 Residual = 0.757334 K = 18 Residual = 0.472641 K = 19 Residual = 0.280781 K = 20 Residual = 0.164021 ITR = 3 Residual = 0.164021 K = 1 Residual = 0.116865 K = 2 Residual = 0.0754133 K = 3 Residual = 0.045688 K = 4 Residual = 0.03016 K = 5 Residual = 0.0198329 K = 6 Residual = 0.0120077 K = 7 Residual = 0.00750916 K = 8 Residual = 0.00545619 K = 9 Residual = 0.00449566 K = 10 Residual = 0.00379011 K = 11 Residual = 0.00347831 K = 12 Residual = 0.00329433 K = 13 Residual = 0.0031818 K = 14 Residual = 0.00309904 K = 15 Residual = 0.00305887 K = 16 Residual = 0.0030335 K = 17 Residual = 0.00299789 K = 18 Residual = 0.00291357 K = 19 Residual = 0.00267515 K = 20 Residual = 0.0023612 ITR = 4 Residual = 0.0023612 K = 1 Residual = 0.00212853 K = 2 Residual = 0.00193195 K = 3 Residual = 0.00183494 K = 4 Residual = 0.0017952 K = 5 Residual = 0.00177621 K = 6 Residual = 0.00176246 K = 7 Residual = 0.00175323 K = 8 Residual = 0.00172536 K = 9 Residual = 0.00165591 K = 10 Residual = 0.00152236 K = 11 Residual = 0.00135436 K = 12 Residual = 0.00107715 K = 13 Residual = 0.000826228 K = 14 Residual = 0.000555383 K = 15 Residual = 0.000339122 K = 16 Residual = 0.000210543 K = 17 Residual = 0.000130116 K = 18 Residual = 8.25018e-05 K = 19 Residual = 5.20703e-05 K = 20 Residual = 3.54808e-05 ITR = 5 Residual = 3.54808e-05 K = 1 Residual = 2.5882e-05 K = 2 Residual = 1.67548e-05 K = 3 Residual = 1.07909e-05 K = 4 Residual = 6.98778e-06 K = 5 Residual = 4.69741e-06 K = 6 Residual = 3.25793e-06 K = 7 Residual = 2.61248e-06 K = 8 Residual = 2.33701e-06 K = 9 Residual = 2.16195e-06 K = 10 Residual = 2.09054e-06 K = 11 Residual = 2.04157e-06 K = 12 Residual = 2.01477e-06 K = 13 Residual = 1.98718e-06 K = 14 Residual = 1.95718e-06 K = 15 Residual = 1.91756e-06 K = 16 Residual = 1.85474e-06 K = 17 Residual = 1.72696e-06 K = 18 Residual = 1.45154e-06 K = 19 Residual = 1.08169e-06 K = 20 Residual = 8.18145e-07 MGMRES Number of iterations = 100 Final residual = 8.18145e-07 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 FEM2D_POISSON_SPARSE: Wrote an ASCII file "lake_values.txt". of the form U ( X(I), Y(I) ) which can be used for plotting. FEM2D_POISSON_SPARSE: Normal end of execution. 19 August 2018 05:19:10 PM