trapezoidal():
  FreeFem++ version.
  Solve a time-dependent boundary value problem in a square.
  Use the trapezoidal method to handle the time variation.
  Report L2 norm, L2 error norm, and L2 relative error norm.
  H =     0.125
  DT =    0.2

  T  ||Exact||   ||Error||  ||Error||/||Exact||

  0  0.5  0.0155547  0.0311093
  0.2  0.409365  0.0205726  0.0502547
  0.4  0.33516  0.0138361  0.041282
  0.6  0.274406  0.0125583  0.0457655
  0.8  0.224664  0.00969895  0.0431708
  1  0.18394  0.00827494  0.0449872
  1.2  0.150597  0.00655083  0.043499
  1.4  0.123298  0.00553163  0.0448637
  1.6  0.100948  0.00439562  0.0435433
  1.8  0.0826494  0.0037083  0.0448678
  2  0.0676676  0.00294562  0.0435307

trapezoidal():
  Normal end of execution.
  current line = 176
exit(0)
 err code 0 ,  mpirank 0