of the various config settings -- they are important settings and should appear earlier. Move the definition of mfem::real_t to config.hpp along with some macros from globals.hpp -- I think this a better place for them. Added support for single precision to ex10 and ex10p. Added explicit compile time checks and error messages to make sure HYPRE is compiled with the same precision as MFEM. Fixed an issue affecting the visualization of the results from ex10 and ex10p on nonconforming meshes.
699 lines
23 KiB
C++
699 lines
23 KiB
C++
// MFEM Example 10 - Parallel Version
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//
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// Compile with: make ex10p
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//
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// Sample runs:
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// mpirun -np 4 ex10p -m ../data/beam-quad.mesh -s 3 -rs 2 -dt 3
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// mpirun -np 4 ex10p -m ../data/beam-tri.mesh -s 3 -rs 2 -dt 3
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// mpirun -np 4 ex10p -m ../data/beam-hex.mesh -s 2 -rs 1 -dt 3
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// mpirun -np 4 ex10p -m ../data/beam-tet.mesh -s 2 -rs 1 -dt 3
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// mpirun -np 4 ex10p -m ../data/beam-wedge.mesh -s 2 -rs 1 -dt 3
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// mpirun -np 4 ex10p -m ../data/beam-quad.mesh -s 14 -rs 2 -dt 0.03 -vs 20
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// mpirun -np 4 ex10p -m ../data/beam-hex.mesh -s 14 -rs 1 -dt 0.05 -vs 20
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// mpirun -np 4 ex10p -m ../data/beam-quad-amr.mesh -s 3 -rs 2 -dt 3
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//
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// Description: This examples solves a time dependent nonlinear elasticity
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// problem of the form dv/dt = H(x) + S v, dx/dt = v, where H is a
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// hyperelastic model and S is a viscosity operator of Laplacian
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// type. The geometry of the domain is assumed to be as follows:
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//
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// +---------------------+
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// boundary --->| |
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// attribute 1 | |
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// (fixed) +---------------------+
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//
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// The example demonstrates the use of nonlinear operators (the
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// class HyperelasticOperator defining H(x)), as well as their
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// implicit time integration using a Newton method for solving an
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// associated reduced backward-Euler type nonlinear equation
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// (class ReducedSystemOperator). Each Newton step requires the
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// inversion of a Jacobian matrix, which is done through a
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// (preconditioned) inner solver. Note that implementing the
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// method HyperelasticOperator::ImplicitSolve is the only
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// requirement for high-order implicit (SDIRK) time integration.
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//
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// We recommend viewing examples 2 and 9 before viewing this
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// example.
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#include "mfem.hpp"
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#include <memory>
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#include <iostream>
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#include <fstream>
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using namespace std;
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using namespace mfem;
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class ReducedSystemOperator;
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/** After spatial discretization, the hyperelastic model can be written as a
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* system of ODEs:
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* dv/dt = -M^{-1}*(H(x) + S*v)
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* dx/dt = v,
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* where x is the vector representing the deformation, v is the velocity field,
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* M is the mass matrix, S is the viscosity matrix, and H(x) is the nonlinear
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* hyperelastic operator.
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*
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* Class HyperelasticOperator represents the right-hand side of the above
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* system of ODEs. */
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class HyperelasticOperator : public TimeDependentOperator
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{
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protected:
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ParFiniteElementSpace &fespace;
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Array<int> ess_tdof_list;
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ParBilinearForm M, S;
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ParNonlinearForm H;
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real_t viscosity;
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HyperelasticModel *model;
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HypreParMatrix *Mmat; // Mass matrix from ParallelAssemble()
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CGSolver M_solver; // Krylov solver for inverting the mass matrix M
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HypreSmoother M_prec; // Preconditioner for the mass matrix M
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/** Nonlinear operator defining the reduced backward Euler equation for the
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velocity. Used in the implementation of method ImplicitSolve. */
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ReducedSystemOperator *reduced_oper;
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/// Newton solver for the reduced backward Euler equation
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NewtonSolver newton_solver;
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/// Solver for the Jacobian solve in the Newton method
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Solver *J_solver;
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/// Preconditioner for the Jacobian solve in the Newton method
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Solver *J_prec;
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mutable Vector z; // auxiliary vector
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public:
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HyperelasticOperator(ParFiniteElementSpace &f, Array<int> &ess_bdr,
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real_t visc, real_t mu, real_t K);
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/// Compute the right-hand side of the ODE system.
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virtual void Mult(const Vector &vx, Vector &dvx_dt) const;
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/** Solve the Backward-Euler equation: k = f(x + dt*k, t), for the unknown k.
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This is the only requirement for high-order SDIRK implicit integration.*/
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virtual void ImplicitSolve(const real_t dt, const Vector &x, Vector &k);
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real_t ElasticEnergy(const ParGridFunction &x) const;
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real_t KineticEnergy(const ParGridFunction &v) const;
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void GetElasticEnergyDensity(const ParGridFunction &x,
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ParGridFunction &w) const;
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virtual ~HyperelasticOperator();
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};
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/** Nonlinear operator of the form:
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k --> (M + dt*S)*k + H(x + dt*v + dt^2*k) + S*v,
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where M and S are given BilinearForms, H is a given NonlinearForm, v and x
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are given vectors, and dt is a scalar. */
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class ReducedSystemOperator : public Operator
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{
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private:
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ParBilinearForm *M, *S;
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ParNonlinearForm *H;
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mutable HypreParMatrix *Jacobian;
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real_t dt;
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const Vector *v, *x;
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mutable Vector w, z;
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const Array<int> &ess_tdof_list;
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public:
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ReducedSystemOperator(ParBilinearForm *M_, ParBilinearForm *S_,
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ParNonlinearForm *H_, const Array<int> &ess_tdof_list);
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/// Set current dt, v, x values - needed to compute action and Jacobian.
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void SetParameters(real_t dt_, const Vector *v_, const Vector *x_);
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/// Compute y = H(x + dt (v + dt k)) + M k + S (v + dt k).
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virtual void Mult(const Vector &k, Vector &y) const;
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/// Compute J = M + dt S + dt^2 grad_H(x + dt (v + dt k)).
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virtual Operator &GetGradient(const Vector &k) const;
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virtual ~ReducedSystemOperator();
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};
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/** Function representing the elastic energy density for the given hyperelastic
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model+deformation. Used in HyperelasticOperator::GetElasticEnergyDensity. */
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class ElasticEnergyCoefficient : public Coefficient
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{
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private:
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HyperelasticModel &model;
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const ParGridFunction &x;
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DenseMatrix J;
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public:
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ElasticEnergyCoefficient(HyperelasticModel &m, const ParGridFunction &x_)
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: model(m), x(x_) { }
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virtual real_t Eval(ElementTransformation &T, const IntegrationPoint &ip);
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virtual ~ElasticEnergyCoefficient() { }
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};
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void InitialDeformation(const Vector &x, Vector &y);
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void InitialVelocity(const Vector &x, Vector &v);
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void visualize(ostream &os, ParMesh *mesh,
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ParGridFunction *deformed_nodes,
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ParGridFunction *field, const char *field_name = NULL,
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bool init_vis = false);
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int main(int argc, char *argv[])
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{
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// 1. Initialize MPI and HYPRE.
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Mpi::Init(argc, argv);
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int myid = Mpi::WorldRank();
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Hypre::Init();
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// 2. Parse command-line options.
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const char *mesh_file = "../data/beam-quad.mesh";
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int ser_ref_levels = 2;
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int par_ref_levels = 0;
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int order = 2;
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int ode_solver_type = 3;
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real_t t_final = 300.0;
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real_t dt = 3.0;
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real_t visc = 1e-2;
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real_t mu = 0.25;
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real_t K = 5.0;
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bool adaptive_lin_rtol = true;
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bool visualization = true;
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int vis_steps = 1;
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OptionsParser args(argc, argv);
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args.AddOption(&mesh_file, "-m", "--mesh",
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"Mesh file to use.");
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args.AddOption(&ser_ref_levels, "-rs", "--refine-serial",
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"Number of times to refine the mesh uniformly in serial.");
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args.AddOption(&par_ref_levels, "-rp", "--refine-parallel",
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"Number of times to refine the mesh uniformly in parallel.");
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args.AddOption(&order, "-o", "--order",
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"Order (degree) of the finite elements.");
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args.AddOption(&ode_solver_type, "-s", "--ode-solver",
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"ODE solver: 1 - Backward Euler, 2 - SDIRK2, 3 - SDIRK3,\n\t"
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" 11 - Forward Euler, 12 - RK2,\n\t"
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" 13 - RK3 SSP, 14 - RK4."
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" 22 - Implicit Midpoint Method,\n\t"
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" 23 - SDIRK23 (A-stable), 24 - SDIRK34");
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args.AddOption(&t_final, "-tf", "--t-final",
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"Final time; start time is 0.");
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args.AddOption(&dt, "-dt", "--time-step",
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"Time step.");
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args.AddOption(&visc, "-v", "--viscosity",
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"Viscosity coefficient.");
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args.AddOption(&mu, "-mu", "--shear-modulus",
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"Shear modulus in the Neo-Hookean hyperelastic model.");
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args.AddOption(&K, "-K", "--bulk-modulus",
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"Bulk modulus in the Neo-Hookean hyperelastic model.");
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args.AddOption(&adaptive_lin_rtol, "-alrtol", "--adaptive-lin-rtol",
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"-no-alrtol", "--no-adaptive-lin-rtol",
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"Enable or disable adaptive linear solver rtol.");
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args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
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"--no-visualization",
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"Enable or disable GLVis visualization.");
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args.AddOption(&vis_steps, "-vs", "--visualization-steps",
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"Visualize every n-th timestep.");
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args.Parse();
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if (!args.Good())
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{
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if (myid == 0)
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{
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args.PrintUsage(cout);
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}
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return 1;
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}
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if (myid == 0)
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{
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args.PrintOptions(cout);
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}
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// 3. Read the serial mesh from the given mesh file on all processors. We can
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// handle triangular, quadrilateral, tetrahedral and hexahedral meshes
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// with the same code.
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Mesh *mesh = new Mesh(mesh_file, 1, 1);
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int dim = mesh->Dimension();
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// 4. Define the ODE solver used for time integration. Several implicit
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// singly diagonal implicit Runge-Kutta (SDIRK) methods, as well as
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// explicit Runge-Kutta methods are available.
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ODESolver *ode_solver;
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switch (ode_solver_type)
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{
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// Implicit L-stable methods
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case 1: ode_solver = new BackwardEulerSolver; break;
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case 2: ode_solver = new SDIRK23Solver(2); break;
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case 3: ode_solver = new SDIRK33Solver; break;
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// Explicit methods
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case 11: ode_solver = new ForwardEulerSolver; break;
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case 12: ode_solver = new RK2Solver(0.5); break; // midpoint method
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case 13: ode_solver = new RK3SSPSolver; break;
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case 14: ode_solver = new RK4Solver; break;
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case 15: ode_solver = new GeneralizedAlphaSolver(0.5); break;
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// Implicit A-stable methods (not L-stable)
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case 22: ode_solver = new ImplicitMidpointSolver; break;
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case 23: ode_solver = new SDIRK23Solver; break;
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case 24: ode_solver = new SDIRK34Solver; break;
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default:
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if (myid == 0)
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{
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cout << "Unknown ODE solver type: " << ode_solver_type << '\n';
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}
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delete mesh;
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return 3;
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}
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// 5. Refine the mesh in serial to increase the resolution. In this example
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// we do 'ser_ref_levels' of uniform refinement, where 'ser_ref_levels' is
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// a command-line parameter.
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for (int lev = 0; lev < ser_ref_levels; lev++)
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{
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mesh->UniformRefinement();
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}
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// 6. Define a parallel mesh by a partitioning of the serial mesh. Refine
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// this mesh further in parallel to increase the resolution. Once the
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// parallel mesh is defined, the serial mesh can be deleted.
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ParMesh *pmesh = new ParMesh(MPI_COMM_WORLD, *mesh);
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delete mesh;
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for (int lev = 0; lev < par_ref_levels; lev++)
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{
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pmesh->UniformRefinement();
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}
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// 7. Define the parallel vector finite element spaces representing the mesh
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// deformation x_gf, the velocity v_gf, and the initial configuration,
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// x_ref. Define also the elastic energy density, w_gf, which is in a
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// discontinuous higher-order space. Since x and v are integrated in time
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// as a system, we group them together in block vector vx, on the unique
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// parallel degrees of freedom, with offsets given by array true_offset.
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H1_FECollection fe_coll(order, dim);
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ParFiniteElementSpace fespace(pmesh, &fe_coll, dim);
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HYPRE_BigInt glob_size = fespace.GlobalTrueVSize();
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if (myid == 0)
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{
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cout << "Number of velocity/deformation unknowns: " << glob_size << endl;
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}
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int true_size = fespace.TrueVSize();
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Array<int> true_offset(3);
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true_offset[0] = 0;
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true_offset[1] = true_size;
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true_offset[2] = 2*true_size;
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BlockVector vx(true_offset);
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ParGridFunction v_gf, x_gf;
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v_gf.MakeTRef(&fespace, vx, true_offset[0]);
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x_gf.MakeTRef(&fespace, vx, true_offset[1]);
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ParGridFunction x_ref(&fespace);
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pmesh->GetNodes(x_ref);
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L2_FECollection w_fec(order + 1, dim);
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ParFiniteElementSpace w_fespace(pmesh, &w_fec);
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ParGridFunction w_gf(&w_fespace);
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// 8. Set the initial conditions for v_gf, x_gf and vx, and define the
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// boundary conditions on a beam-like mesh (see description above).
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VectorFunctionCoefficient velo(dim, InitialVelocity);
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v_gf.ProjectCoefficient(velo);
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v_gf.SetTrueVector();
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VectorFunctionCoefficient deform(dim, InitialDeformation);
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x_gf.ProjectCoefficient(deform);
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x_gf.SetTrueVector();
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v_gf.SetFromTrueVector(); x_gf.SetFromTrueVector();
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Array<int> ess_bdr(fespace.GetMesh()->bdr_attributes.Max());
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ess_bdr = 0;
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ess_bdr[0] = 1; // boundary attribute 1 (index 0) is fixed
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// 9. Initialize the hyperelastic operator, the GLVis visualization and print
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// the initial energies.
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HyperelasticOperator oper(fespace, ess_bdr, visc, mu, K);
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socketstream vis_v, vis_w;
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if (visualization)
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{
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char vishost[] = "localhost";
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int visport = 19916;
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vis_v.open(vishost, visport);
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vis_v.precision(8);
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visualize(vis_v, pmesh, &x_gf, &v_gf, "Velocity", true);
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// Make sure all ranks have sent their 'v' solution before initiating
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// another set of GLVis connections (one from each rank):
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MPI_Barrier(pmesh->GetComm());
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vis_w.open(vishost, visport);
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if (vis_w)
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{
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oper.GetElasticEnergyDensity(x_gf, w_gf);
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vis_w.precision(8);
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visualize(vis_w, pmesh, &x_gf, &w_gf, "Elastic energy density", true);
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}
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if (myid == 0)
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{
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cout << "GLVis visualization paused."
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<< " Press space (in the GLVis window) to resume it.\n";
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}
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}
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real_t ee0 = oper.ElasticEnergy(x_gf);
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real_t ke0 = oper.KineticEnergy(v_gf);
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if (myid == 0)
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{
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cout << "initial elastic energy (EE) = " << ee0 << endl;
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cout << "initial kinetic energy (KE) = " << ke0 << endl;
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cout << "initial total energy (TE) = " << (ee0 + ke0) << endl;
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}
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real_t t = 0.0;
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oper.SetTime(t);
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ode_solver->Init(oper);
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// 10. Perform time-integration
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// (looping over the time iterations, ti, with a time-step dt).
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bool last_step = false;
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for (int ti = 1; !last_step; ti++)
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{
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real_t dt_real = min(dt, t_final - t);
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ode_solver->Step(vx, t, dt_real);
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last_step = (t >= t_final - 1e-8*dt);
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if (last_step || (ti % vis_steps) == 0)
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{
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v_gf.SetFromTrueVector(); x_gf.SetFromTrueVector();
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real_t ee = oper.ElasticEnergy(x_gf);
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real_t ke = oper.KineticEnergy(v_gf);
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if (myid == 0)
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{
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cout << "step " << ti << ", t = " << t << ", EE = " << ee
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<< ", KE = " << ke << ", ΔTE = " << (ee+ke)-(ee0+ke0) << endl;
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}
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if (visualization)
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{
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visualize(vis_v, pmesh, &x_gf, &v_gf);
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if (vis_w)
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{
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oper.GetElasticEnergyDensity(x_gf, w_gf);
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visualize(vis_w, pmesh, &x_gf, &w_gf);
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}
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}
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}
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}
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// 11. Save the displaced mesh, the velocity and elastic energy.
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{
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v_gf.SetFromTrueVector(); x_gf.SetFromTrueVector();
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GridFunction *nodes = &x_gf;
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int owns_nodes = 0;
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pmesh->SwapNodes(nodes, owns_nodes);
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ostringstream mesh_name, velo_name, ee_name;
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mesh_name << "deformed." << setfill('0') << setw(6) << myid;
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velo_name << "velocity." << setfill('0') << setw(6) << myid;
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ee_name << "elastic_energy." << setfill('0') << setw(6) << myid;
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ofstream mesh_ofs(mesh_name.str().c_str());
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mesh_ofs.precision(8);
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pmesh->Print(mesh_ofs);
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pmesh->SwapNodes(nodes, owns_nodes);
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ofstream velo_ofs(velo_name.str().c_str());
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velo_ofs.precision(8);
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v_gf.Save(velo_ofs);
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ofstream ee_ofs(ee_name.str().c_str());
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ee_ofs.precision(8);
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oper.GetElasticEnergyDensity(x_gf, w_gf);
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w_gf.Save(ee_ofs);
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}
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// 12. Free the used memory.
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delete ode_solver;
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delete pmesh;
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return 0;
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}
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void visualize(ostream &os, ParMesh *mesh,
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ParGridFunction *deformed_nodes,
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ParGridFunction *field, const char *field_name, bool init_vis)
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{
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if (!os)
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{
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return;
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}
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GridFunction *nodes = deformed_nodes;
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int owns_nodes = 0;
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mesh->SwapNodes(nodes, owns_nodes);
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os << "parallel " << mesh->GetNRanks()
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<< " " << mesh->GetMyRank() << "\n";
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os << "solution\n" << *mesh << *field;
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|
|
|
mesh->SwapNodes(nodes, owns_nodes);
|
|
|
|
if (init_vis)
|
|
{
|
|
os << "window_size 800 800\n";
|
|
os << "window_title '" << field_name << "'\n";
|
|
if (mesh->SpaceDimension() == 2)
|
|
{
|
|
os << "view 0 0\n"; // view from top
|
|
os << "keys jl\n"; // turn off perspective and light
|
|
}
|
|
os << "keys cm\n"; // show colorbar and mesh
|
|
// update value-range; keep mesh-extents fixed
|
|
os << "autoscale value\n";
|
|
os << "pause\n";
|
|
}
|
|
os << flush;
|
|
}
|
|
|
|
|
|
ReducedSystemOperator::ReducedSystemOperator(
|
|
ParBilinearForm *M_, ParBilinearForm *S_, ParNonlinearForm *H_,
|
|
const Array<int> &ess_tdof_list_)
|
|
: Operator(M_->ParFESpace()->TrueVSize()), M(M_), S(S_), H(H_),
|
|
Jacobian(NULL), dt(0.0), v(NULL), x(NULL), w(height), z(height),
|
|
ess_tdof_list(ess_tdof_list_)
|
|
{ }
|
|
|
|
void ReducedSystemOperator::SetParameters(real_t dt_, const Vector *v_,
|
|
const Vector *x_)
|
|
{
|
|
dt = dt_; v = v_; x = x_;
|
|
}
|
|
|
|
void ReducedSystemOperator::Mult(const Vector &k, Vector &y) const
|
|
{
|
|
// compute: y = H(x + dt*(v + dt*k)) + M*k + S*(v + dt*k)
|
|
add(*v, dt, k, w);
|
|
add(*x, dt, w, z);
|
|
H->Mult(z, y);
|
|
M->TrueAddMult(k, y);
|
|
S->TrueAddMult(w, y);
|
|
y.SetSubVector(ess_tdof_list, 0.0);
|
|
}
|
|
|
|
Operator &ReducedSystemOperator::GetGradient(const Vector &k) const
|
|
{
|
|
delete Jacobian;
|
|
SparseMatrix *localJ = Add(1.0, M->SpMat(), dt, S->SpMat());
|
|
add(*v, dt, k, w);
|
|
add(*x, dt, w, z);
|
|
localJ->Add(dt*dt, H->GetLocalGradient(z));
|
|
Jacobian = M->ParallelAssemble(localJ);
|
|
delete localJ;
|
|
HypreParMatrix *Je = Jacobian->EliminateRowsCols(ess_tdof_list);
|
|
delete Je;
|
|
return *Jacobian;
|
|
}
|
|
|
|
ReducedSystemOperator::~ReducedSystemOperator()
|
|
{
|
|
delete Jacobian;
|
|
}
|
|
|
|
|
|
HyperelasticOperator::HyperelasticOperator(ParFiniteElementSpace &f,
|
|
Array<int> &ess_bdr, real_t visc,
|
|
real_t mu, real_t K)
|
|
: TimeDependentOperator(2*f.TrueVSize(), (real_t) 0.0), fespace(f),
|
|
M(&fespace), S(&fespace), H(&fespace),
|
|
viscosity(visc), M_solver(f.GetComm()), newton_solver(f.GetComm()),
|
|
z(height/2)
|
|
{
|
|
#if defined(MFEM_USE_DOUBLE)
|
|
const real_t rel_tol = 1e-8;
|
|
const real_t newton_abs_tol = 0.0;
|
|
#elif defined(MFEM_USE_SINGLE)
|
|
const real_t rel_tol = 1e-3;
|
|
const real_t newton_abs_tol = 1e-4;
|
|
#else
|
|
#error "Only single and double precision are supported!"
|
|
const real_t rel_tol = real_t(1);
|
|
const real_t newton_abs_tol = real_t(0);
|
|
#endif
|
|
const int skip_zero_entries = 0;
|
|
|
|
const real_t ref_density = 1.0; // density in the reference configuration
|
|
ConstantCoefficient rho0(ref_density);
|
|
M.AddDomainIntegrator(new VectorMassIntegrator(rho0));
|
|
M.Assemble(skip_zero_entries);
|
|
M.Finalize(skip_zero_entries);
|
|
Mmat = M.ParallelAssemble();
|
|
fespace.GetEssentialTrueDofs(ess_bdr, ess_tdof_list);
|
|
HypreParMatrix *Me = Mmat->EliminateRowsCols(ess_tdof_list);
|
|
delete Me;
|
|
|
|
M_solver.iterative_mode = false;
|
|
M_solver.SetRelTol(rel_tol);
|
|
M_solver.SetAbsTol(0.0);
|
|
M_solver.SetMaxIter(30);
|
|
M_solver.SetPrintLevel(0);
|
|
M_prec.SetType(HypreSmoother::Jacobi);
|
|
M_solver.SetPreconditioner(M_prec);
|
|
M_solver.SetOperator(*Mmat);
|
|
|
|
model = new NeoHookeanModel(mu, K);
|
|
H.AddDomainIntegrator(new HyperelasticNLFIntegrator(model));
|
|
H.SetEssentialTrueDofs(ess_tdof_list);
|
|
|
|
ConstantCoefficient visc_coeff(viscosity);
|
|
S.AddDomainIntegrator(new VectorDiffusionIntegrator(visc_coeff));
|
|
S.Assemble(skip_zero_entries);
|
|
S.Finalize(skip_zero_entries);
|
|
|
|
reduced_oper = new ReducedSystemOperator(&M, &S, &H, ess_tdof_list);
|
|
|
|
HypreSmoother *J_hypreSmoother = new HypreSmoother;
|
|
J_hypreSmoother->SetType(HypreSmoother::l1Jacobi);
|
|
J_hypreSmoother->SetPositiveDiagonal(true);
|
|
J_prec = J_hypreSmoother;
|
|
|
|
MINRESSolver *J_minres = new MINRESSolver(f.GetComm());
|
|
J_minres->SetRelTol(rel_tol);
|
|
J_minres->SetAbsTol(0.0);
|
|
J_minres->SetMaxIter(300);
|
|
J_minres->SetPrintLevel(-1);
|
|
J_minres->SetPreconditioner(*J_prec);
|
|
J_solver = J_minres;
|
|
|
|
newton_solver.iterative_mode = false;
|
|
newton_solver.SetSolver(*J_solver);
|
|
newton_solver.SetOperator(*reduced_oper);
|
|
newton_solver.SetPrintLevel(1); // print Newton iterations
|
|
newton_solver.SetRelTol(rel_tol);
|
|
newton_solver.SetAbsTol(newton_abs_tol);
|
|
newton_solver.SetAdaptiveLinRtol(2, 0.5, 0.9);
|
|
newton_solver.SetMaxIter(10);
|
|
}
|
|
|
|
void HyperelasticOperator::Mult(const Vector &vx, Vector &dvx_dt) const
|
|
{
|
|
// Create views to the sub-vectors v, x of vx, and dv_dt, dx_dt of dvx_dt
|
|
int sc = height/2;
|
|
Vector v(vx.GetData() + 0, sc);
|
|
Vector x(vx.GetData() + sc, sc);
|
|
Vector dv_dt(dvx_dt.GetData() + 0, sc);
|
|
Vector dx_dt(dvx_dt.GetData() + sc, sc);
|
|
|
|
H.Mult(x, z);
|
|
if (viscosity != 0.0)
|
|
{
|
|
S.TrueAddMult(v, z);
|
|
z.SetSubVector(ess_tdof_list, 0.0);
|
|
}
|
|
z.Neg(); // z = -z
|
|
M_solver.Mult(z, dv_dt);
|
|
|
|
dx_dt = v;
|
|
}
|
|
|
|
void HyperelasticOperator::ImplicitSolve(const real_t dt,
|
|
const Vector &vx, Vector &dvx_dt)
|
|
{
|
|
int sc = height/2;
|
|
Vector v(vx.GetData() + 0, sc);
|
|
Vector x(vx.GetData() + sc, sc);
|
|
Vector dv_dt(dvx_dt.GetData() + 0, sc);
|
|
Vector dx_dt(dvx_dt.GetData() + sc, sc);
|
|
|
|
// By eliminating kx from the coupled system:
|
|
// kv = -M^{-1}*[H(x + dt*kx) + S*(v + dt*kv)]
|
|
// kx = v + dt*kv
|
|
// we reduce it to a nonlinear equation for kv, represented by the
|
|
// reduced_oper. This equation is solved with the newton_solver
|
|
// object (using J_solver and J_prec internally).
|
|
reduced_oper->SetParameters(dt, &v, &x);
|
|
Vector zero; // empty vector is interpreted as zero r.h.s. by NewtonSolver
|
|
newton_solver.Mult(zero, dv_dt);
|
|
MFEM_VERIFY(newton_solver.GetConverged(), "Newton solver did not converge.");
|
|
add(v, dt, dv_dt, dx_dt);
|
|
}
|
|
|
|
real_t HyperelasticOperator::ElasticEnergy(const ParGridFunction &x) const
|
|
{
|
|
return H.GetEnergy(x);
|
|
}
|
|
|
|
real_t HyperelasticOperator::KineticEnergy(const ParGridFunction &v) const
|
|
{
|
|
real_t loc_energy = 0.5*M.InnerProduct(v, v);
|
|
real_t energy;
|
|
MPI_Allreduce(&loc_energy, &energy, 1, MPITypeMap<real_t>::mpi_type,
|
|
MPI_SUM, fespace.GetComm());
|
|
return energy;
|
|
}
|
|
|
|
void HyperelasticOperator::GetElasticEnergyDensity(
|
|
const ParGridFunction &x, ParGridFunction &w) const
|
|
{
|
|
ElasticEnergyCoefficient w_coeff(*model, x);
|
|
w.ProjectCoefficient(w_coeff);
|
|
}
|
|
|
|
HyperelasticOperator::~HyperelasticOperator()
|
|
{
|
|
delete J_solver;
|
|
delete J_prec;
|
|
delete reduced_oper;
|
|
delete model;
|
|
delete Mmat;
|
|
}
|
|
|
|
|
|
real_t ElasticEnergyCoefficient::Eval(ElementTransformation &T,
|
|
const IntegrationPoint &ip)
|
|
{
|
|
model.SetTransformation(T);
|
|
x.GetVectorGradient(T, J);
|
|
// return model.EvalW(J); // in reference configuration
|
|
return model.EvalW(J)/J.Det(); // in deformed configuration
|
|
}
|
|
|
|
|
|
void InitialDeformation(const Vector &x, Vector &y)
|
|
{
|
|
// set the initial configuration to be the same as the reference, stress
|
|
// free, configuration
|
|
y = x;
|
|
}
|
|
|
|
void InitialVelocity(const Vector &x, Vector &v)
|
|
{
|
|
const int dim = x.Size();
|
|
const real_t s = 0.1/64.;
|
|
|
|
v = 0.0;
|
|
v(dim-1) = s*x(0)*x(0)*(8.0-x(0));
|
|
v(0) = -s*x(0)*x(0);
|
|
}
|