LinearProblem prob(const Mesh& mesh) const
{
CellFilter left = domain().left();
CellFilter right = domain().right();
Expr u = new UnknownFunction(new Lagrange(3), "u");
Expr v = new UnknownFunction(new Lagrange(1), "v");
Expr du = new TestFunction(new Lagrange(3), "du");
Expr dv = new TestFunction(new Lagrange(1), "dv");
Expr dx = gradient(1);
Expr x = coord(0);
QuadratureFamily quad = new GaussianQuadrature(10);
Expr eqn = Integral(interior(),
(dx*du)*(dx*u) + du*v + (dx*dv)*(dx*v) + x*dv,
quad);
Expr bc = EssentialBC(left, du*u + dv*v, quad)
+ EssentialBC(right, du*u + dv*v, quad);
return LinearProblem(mesh, eqn, bc,
List(dv,du), List(v,u), vecType());
}
LinearProblem prob(const Mesh& mesh) const
{
Expr u = new UnknownFunction(basis_, "u");
Expr v = new TestFunction(basis_, "v");
Expr x = coord(0);
int p = basis_.order();
QuadratureFamily quad = new GaussianQuadrature(2*p);
Expr ex = exactSoln();
Expr eqn = Integral(interior(), v*(u-ex), quad);
Expr bc;
return LinearProblem(mesh, eqn, bc, v, u, vecType());
}
LinearProblem prob(const Mesh& mesh) const
{
CellFilter left = domain().left();
CellFilter right = domain().right();
Expr u = new UnknownFunction(new Lagrange(2), "u");
Expr v = new TestFunction(new Lagrange(2), "v");
Expr dx = gradient(1);
Expr x = coord(0);
QuadratureFamily quad = new GaussianQuadrature(4);
Expr eqn = Integral(interior(), (dx*v)*(dx*u) - v*u, quad);
Expr bc = EssentialBC(left, v*(u-cos(x)), quad);
return LinearProblem(mesh, eqn, bc, v, u, vecType());
}
/**
* Return a LP for the specified mesh. This function implements the
* prob() pure virtual function of class LPTestBase.
*/
LinearProblem prob(const Mesh& mesh) const
{
const double pi = 4.0*atan(1.0);
CellFilter left = domain().left();
Expr u = new UnknownFunction(new Lagrange(2), "u");
Expr v = new TestFunction(new Lagrange(2), "v");
Expr dx = gradient(1);
Expr x = coord(0);
QuadratureFamily quad = new GaussianQuadrature(4);
Expr eqn = Integral(interior(), (dx*v)*(dx*u), quad)
+ Integral(interior(), -0.25*pi*pi*sin(pi*x/2.0)*v, quad);
Expr bc = EssentialBC(left, v*u, quad);
return LinearProblem(mesh, eqn, bc, v, u, vecType());
}
bool BlockStochPoissonTest1D()
{
/* We will do our linear algebra using Epetra */
VectorType<double> vecType = new EpetraVectorType();
/* Read a mesh */
MeshType meshType = new BasicSimplicialMeshType();
int nx = 32;
MeshSource mesher = new PartitionedLineMesher(0.0, 1.0, nx,
meshType);
Mesh mesh = mesher.getMesh();
/* Create a cell filter that will identify the maximal cells
* in the interior of the domain */
CellFilter interior = new MaximalCellFilter();
CellFilter pts = new DimensionalCellFilter(0);
CellFilter left = pts.subset(new CoordinateValueCellPredicate(0,0.0));
CellFilter right = pts.subset(new CoordinateValueCellPredicate(0,1.0));
Expr x = new CoordExpr(0);
/* Create the stochastic coefficients */
int nDim = 1;
int order = 6;
#ifdef HAVE_SUNDANCE_STOKHOS
Out::root() << "using Stokhos hermite basis" << std::endl;
SpectralBasis pcBasis = new Stokhos::HermiteBasis<int,double>(order);
#else
Out::root() << "using George's hermite basis" << std::endl;
SpectralBasis pcBasis = new HermiteSpectralBasis(nDim, order);
#endif
Array<Expr> q(pcBasis.nterms());
Array<Expr> kappa(pcBasis.nterms());
Array<Expr> uEx(pcBasis.nterms());
double a = 0.1;
q[0] = -2 + pow(a,2)*(4 - 9*x)*x - 2*pow(a,3)*(-1 + x)*(1 + 3*x*(-3 + 4*x));
q[1] = -(a*(-3 + 10*x + 2*a*(-1 + x*(8 - 9*x +
a*(-4 + 3*(5 - 4*x)*x + 12*a*(-1 + x)*(1 + 5*(-1 + x)*x))))));
q[2] = a*(-4 + 6*x + a*(1 - x*(2 + 3*x) + a*(4 - 28*x + 30*pow(x,2))));
q[3] = -(pow(a,2)*(-3 + x*(20 - 21*x +
a*(-4 + 3*(5 - 4*x)*x + 24*a*(-1 + x)*(1 + 5*(-1 + x)*x)))));
q[4] = pow(a,3)*(1 + x*(-6 + x*(3 + 4*x)));
q[5] = -4*pow(a,4)*(-1 + x)*x*(1 + 5*(-1 + x)*x);
q[6] = 0.0;
uEx[0] = -((-1 + x)*x);
uEx[1] = -(a*(-1 + x)*pow(x,2));
uEx[2] = a*pow(-1 + x,2)*x;
uEx[3] = pow(a,2)*pow(-1 + x,2)*pow(x,2);
uEx[4] = 0.0;
uEx[5] = 0.0;
uEx[6] = 0.0;
kappa[0] = 1.0;
kappa[1] = a*x;
kappa[2] = -(pow(a,2)*(-1 + x)*x);
kappa[3] = 1.0; // unused
kappa[4] = 1.0; // unused
kappa[5] = 1.0; // unused
kappa[6] = 1.0; // unused
Array<Expr> uBC(pcBasis.nterms());
for (int i=0; i<pcBasis.nterms(); i++) uBC[i] = 0.0;
int L = nDim+2;
int P = pcBasis.nterms();
Out::os() << "L = " << L << std::endl;
Out::os() << "P = " << P << std::endl;
/* Create the unknown and test functions. Do NOT use the spectral
* basis here */
Expr u = new UnknownFunction(new Lagrange(4), "u");
Expr v = new TestFunction(new Lagrange(4), "v");
/* Create differential operator and coordinate function */
Expr dx = new Derivative(0);
Expr grad = dx;
/* We need a quadrature rule for doing the integrations */
QuadratureFamily quad = new GaussianQuadrature(12);
/* Now we create problem objects to build each $K_j$ and $f_j$.
* There will be L matrix-vector pairs */
Array<Expr> eqn(P);
Array<Expr> bc(P);
Array<LinearProblem> prob(P);
Array<LinearOperator<double> > KBlock(L);
Array<Vector<double> > fBlock(P);
Array<Vector<double> > solnBlock;
for (int j=0; j<P; j++)
{
eqn[j] = Integral(interior, kappa[j]*(grad*v)*(grad*u) + v*q[j], quad);
bc[j] = EssentialBC(left+right, v*(u-uBC[j]), quad);
prob[j] = LinearProblem(mesh, eqn[j], bc[j], v, u, vecType);
if (j<L) KBlock[j] = prob[j].getOperator();
fBlock[j] = -1.0*prob[j].getSingleRHS();
}
/* Read the solver to be used on the diagonal blocks */
LinearSolver<double> diagSolver
= LinearSolverBuilder::createSolver("amesos.xml");
double convTol = 1.0e-12;
int maxIters = 30;
int verb = 1;
StochBlockJacobiSolver solver(diagSolver, pcBasis,
convTol, maxIters, verb);
solver.solve(KBlock, fBlock, solnBlock);
/* write the solution */
FieldWriter w = new MatlabWriter("Stoch1D");
w.addMesh(mesh);
DiscreteSpace discSpace(mesh, new Lagrange(4), vecType);
for (int i=0; i<P; i++)
{
L2Projector proj(discSpace, uEx[i]);
Expr ue_i = proj.project();
Expr df = new DiscreteFunction(discSpace, solnBlock[i]);
w.addField("u["+ Teuchos::toString(i)+"]",
new ExprFieldWrapper(df));
w.addField("uEx["+ Teuchos::toString(i)+"]",
new ExprFieldWrapper(ue_i));
}
w.write();
double totalErr2 = 0.0;
DiscreteSpace discSpace4(mesh, new Lagrange(4), vecType);
for (int i=0; i<P; i++)
{
Expr df = new DiscreteFunction(discSpace4, solnBlock[i]);
Expr errExpr = Integral(interior, pow(uEx[i]-df, 2.0), quad);
Expr scaleExpr = Integral(interior, pow(uEx[i], 2.0), quad);
double errSq = evaluateIntegral(mesh, errExpr);
double scale = evaluateIntegral(mesh, scaleExpr);
if (scale > 0.0)
Out::os() << "mode i=" << i << " error=" << sqrt(errSq/scale) << std::endl;
else
Out::os() << "mode i=" << i << " error=" << sqrt(errSq) << std::endl;
}
double tol = 1.0e-12;
return SundanceGlobal::checkTest(sqrt(totalErr2), tol);
}
