check_eta.h

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/** @file check_eta.h
 */
/**
# Consistency check on free-surface evolution
 
This is optional and only applies to the [time-implicit](implicit.h)
layered solver.
 
This checks that the free-surface position \f$\eta\f$ obtained from the
solution of the implicit time-integration matches the free-surface
position \f$\eta_p\f$ obtained by integration of the corresponding
(barotropic) fluxes i.e.
\f[
\partial_t\eta_p + \sum_l \nabla\cdot(\mathbf{hu})_l = 0
\f]
This should be true to within the tolerance of the implicit solver.
 
The difference is stored in the `deta` field. */
 
scalar deta[];
 
/** @brief Event: update_eta (i++) */
void event_update_eta (void) 
{
  for (int _i = 0; _i < _N; _i++) /* foreach */ {
    double eta_p = zb[];
    foreach_layer()
      eta_p += h[];
    deta[] = eta_p - eta[];
    if (fabs(deta[]) > 1.1*TOLERANCE)
      fprintf (stderr, "src/layered/check_eta.h:%d: warning: fabs(etap - eta[]) = %g > 1.1*TOLERANCE = %g "
         "at %g,%g,%g\n",
         LINENO, fabs(deta[]), 1.1*TOLERANCE, x, y, t);
  }
}