Program mlstest

The program mlstest is an extensive example code demonstrating possibilities of usage of LASPack routines. It solves a Poisson problem in a 1D or 2D unit domain by a specified multilevel solver.

All input parameters have to be set interactively. The output contains the convergence history as well as the determined middle convergence rates.

For example, a three-grid solution by means of the V-cycle multigrid method with the Gauss-Seidel smoothing (two pre-smoothing and one post-smoothing iteration) and the ILU preconditioned CG method on the coarsest grid (20 iterations) yields for a grid on the finest level:

  0. iteration ... accuracy =  1.0000e+00
  1. iteration ... accuracy =  4.3033e-02
  2. iteration ... accuracy =  3.3534e-03
  3. iteration ... accuracy =  2.8452e-04
  4. iteration ... accuracy =  2.4934e-05
  5. iteration ... accuracy =  2.2565e-06
  6. iteration ... accuracy =  2.0996e-07
  7. iteration ... accuracy =  1.9860e-08
  8. iteration ... accuracy =  7.6893e-09

  CPU time:    0.67 s

Middle contraction rate
  referred to one iteration:  9.677e-02
  referred to 1 s CPU time:   7.751e-13