testproblem9.h

Dolfin provide a high-performance linear algebra library

// Copyright (C) 2003-2006 Anders Logg.
// Licensed under the GNU LGPL Version 2.1.
//
// First added:  2003
// Last changed: 2006-08-21

#include <dolfin.h>

using namespace dolfin;

class TestProblem9 : public ODE
{
public:
  
  TestProblem9() : ODE(3, 30.0)
  {
    message("A mixed stiff/nonstiff test problem.");

    lambda = 1000.0;
  }

  void u0(uBlasVector& u)
  {
    u(0) = 0.0;
    u(1) = 1.0;
    u(2) = 1.0;
  }
  
  void f(const uBlasVector& u, real t, uBlasVector& y)
  {
    y(0) = u(1);
    y(1) = -(1.0 - u(2))*u(0);
    y(2) = -lambda * (u(0)*u(0) + u(1)*u(1)) * u(2);
  }

private:

  real lambda;

};