C++ DistributedTetrahedralMesh::GetNodeIteratorBegin方法代码示例

//.........这里部分代码省略.........
                    iter->SetAttribute(bath_id2);
                }
            }
            else
            {
                //IDs default to 0, but we want to be safe
                iter->SetAttribute(tissue_id);
            }
        }

        /* HOW_TO_TAG Cardiac/Problem definition
         * Tell Chaste that a mesh has been modified
         *
         * Since we have modified the mesh by setting element attributes, we need to inform Chaste of this fact.
         * If we do not, problems will arise when [wiki:UserTutorials/CardiacCheckpointingAndRestarting checkpointing],
         * since the code that saves the simulation state will assume that it can just reuse the original mesh files,
         * and thus won't save the new element attributes.
         *
         * (Some mesh modifications, that use methods on the mesh class directly, will automatically record that
         * the mesh has been modified.  Since we're just modifying elements, this information isn't propagated at
         * present.)
         */
        mesh.SetMeshHasChangedSinceLoading();

        /*
         * The external conductivity can set two ways:
         *  * the default conductivity in the bath is set with {{{SetBathConductivity(double)}}}
         *  * heterogeneous overides can be set with {{{SetBathMultipleConductivities(std::map<unsigned, double> )}}}
         */

        HeartConfig::Instance()->SetBathConductivity(7.0);  //bath_id1 tags will take the default value (actually 7.0 is the default)
        std::map<unsigned, double> multiple_bath_conductivities;
        multiple_bath_conductivities[bath_id2] = 6.5;  // mS/cm

        HeartConfig::Instance()->SetBathMultipleConductivities(multiple_bath_conductivities);


        /* Now we define the electrodes. First define the magnitude of the electrodes
         * (ie the magnitude of the boundary extracellular stimulus), and the duration
         * it lasts for. Currently, electrodes switch on at time 0 and have constant magnitude
         * until they are switched off. (Note that this test has a small range of
         * magnitudes that will work, perhaps because the electrodes are close to the tissue).
         */
        // For default conductivities and explicit cell model -1e4 is under threshold, -1.4e4 too high - crashes the cell model
        // For heterogeneous conductivities as given, -1e4 is under threshold
        double magnitude = -14.0e3; // uA/cm^2
        double start_time = 0.0;
        double duration = 1; //ms

        /* Electrodes work in two ways: the first electrode applies an input flux, and
         * the opposite electrode can either be grounded or apply an equal and opposite
         * flux (ie an output flux). The `false` here indicates the second electrode
         * is not grounded, ie has an equal and opposite flux. The "0" indicates
         * that the electrodes should be applied to the bounding surfaces in the x-direction
         * (1 would be y-direction, 2 z-direction), which are X=0.0 and X=0.1 in the given mesh.
         * (This explains why the full mesh ought to be rectangular/cuboid - the nodes on
         * x=xmin and x=xmax ought to be form two surfaces of equal area.
         */
        HeartConfig::Instance()->SetElectrodeParameters(false, 0, magnitude, start_time, duration);

        /* Now create the problem class, using the cell factory and passing
         * in `true` as the second argument to indicate we are solving a bath
         * problem..
         */
        BidomainProblem<2> bidomain_problem( &cell_factory, true );

        /* ..set the mesh and electrodes.. */
        bidomain_problem.SetMesh(&mesh);

        /* ..and solve as before. */
        bidomain_problem.Initialise();
        bidomain_problem.Solve();

        /* The results can be visualised as before. '''Note:''' The voltage is only
         * defined at cardiac nodes (a node contained in ''any'' cardiac element), but
         * for visualisation and computation a 'fake' value of ZERO is given for the
         * voltage at bath nodes.
         *
         * Finally, we can check that an AP was induced in any of the cardiac
         * cells. We use a `ReplicatableVector` as before, and make sure we
         * only check the voltage at cardiac cells.
         */
        Vec solution = bidomain_problem.GetSolution(); // the Vs and phi_e's, as a PetSc vector
        ReplicatableVector solution_repl(solution);

        bool ap_triggered = false;
        for (AbstractTetrahedralMesh<2,2>::NodeIterator iter = mesh.GetNodeIteratorBegin();
             iter != mesh.GetNodeIteratorEnd();
             ++iter)
        {
            if (HeartRegionCode::IsRegionTissue( iter->GetRegion() ))
            {
                if (solution_repl[2*iter->GetIndex()] > 0.0) // 2*i, ie the voltage for this node (would be 2*i+1 for phi_e for this node)
                {
                    ap_triggered = true;
                }
            }
        }
        TS_ASSERT(ap_triggered);
    }