int main(int argc, char **argv)
{
SNES snes; /* nonlinear solver */
Mat A,J; /* Jacobian,preconditioner matrix */
Vec u,r; /* solution, residual vectors */
AppCtx user; /* user-defined work context */
PetscReal error = 0.0; /* L_2 error in the solution */
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL, help);CHKERRQ(ierr);
ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
ierr = SNESCreate(PETSC_COMM_WORLD, &snes);CHKERRQ(ierr);
ierr = CreateMesh(PETSC_COMM_WORLD, &user, &user.dm);CHKERRQ(ierr);
ierr = SNESSetDM(snes, user.dm);CHKERRQ(ierr);
ierr = SetupExactSolution(&user);CHKERRQ(ierr);
ierr = SetupQuadrature(&user);CHKERRQ(ierr);
ierr = SetupSection(user.dm, &user);CHKERRQ(ierr);
ierr = DMCreateGlobalVector(user.dm, &u);CHKERRQ(ierr);
ierr = VecDuplicate(u, &r);CHKERRQ(ierr);
ierr = DMSetMatType(user.dm,MATAIJ);CHKERRQ(ierr);
ierr = DMCreateMatrix(user.dm, &J);CHKERRQ(ierr);
A = J;
ierr = DMSNESSetFunctionLocal(user.dm, (PetscErrorCode (*)(DM,Vec,Vec,void*))FormFunctionLocal,&user);CHKERRQ(ierr);
ierr = DMSNESSetJacobianLocal(user.dm, (PetscErrorCode (*)(DM,Vec,Mat,Mat,void*))FormJacobianLocal,&user);CHKERRQ(ierr);
ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
{
PetscReal res;
/* Check discretization error */
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
/* ierr = ComputeError(u, &error, &user);CHKERRQ(ierr); */
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %g\n", error);CHKERRQ(ierr);
/* Check residual */
ierr = SNESComputeFunction(snes,u,r);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial Residual\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Residual: %g\n", res);CHKERRQ(ierr);
}
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = SNESDestroy(&snes);CHKERRQ(ierr);
ierr = DMDestroy(&user.dm);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
/*
FormFunctionLocal - Form the local residual F from the local input X
Input Parameters:
+ dm - The mesh
. X - Local input vector
- user - The user context
Output Parameter:
. F - Local output vector
Note:
We form the residual one batch of elements at a time. This allows us to offload work onto an accelerator,
like a GPU, or vectorize on a multicore machine.
.seealso: FormJacobianLocal()
*/
PetscErrorCode FormFunctionLocal(DM dm, Vec X, Vec F, AppCtx *user)
{
const PetscInt debug = user->debug;
const PetscInt dim = user->dim;
PetscReal *coords, *v0, *J, *invJ, *detJ;
PetscScalar *elemVec, *u;
const PetscInt numCells = cEnd - cStart;
PetscInt cellDof = 0;
PetscInt maxQuad = 0;
PetscInt jacSize = 1;
PetscInt cStart, cEnd, c, field;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = PetscLogEventBegin(user->residualEvent,0,0,0,0);CHKERRQ(ierr);
ierr = VecSet(F, 0.0);CHKERRQ(ierr);
ierr = DMDAGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
for(field = 0; field < numFields; ++field) {
PetscInt dof = 1;
for(d = 0; d < dim; ++d) {dof *= user->q[field].numBasisFuncs*user->q[field].numComponents;}
cellDof += dof;
maxQuad = PetscMax(maxQuad, user->q[field].numQuadPoints);
}
for(d = 0; d < dim; ++d) {jacSize *= maxQuad;}
ierr = PetscMalloc3(dim,PetscReal,&coords,dim,PetscReal,&v0,jacSize,PetscReal,&J);CHKERRQ(ierr);
ierr = PetscMalloc4(numCells*cellDof,PetscScalar,&u,numCells*jacSize,PetscReal,&invJ,numCells,PetscReal,&detJ,numCells*cellDof,PetscScalar,&elemVec);CHKERRQ(ierr);
for(c = cStart; c < cEnd; ++c) {
const PetscScalar *x;
PetscInt i;
ierr = DMDAComputeCellGeometry(dm, c, v0, J, &invJ[c*jacSize], &detJ[c]);CHKERRQ(ierr);
if (detJ[c] <= 0.0) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Invalid determinant %g for element %d", detJ[c], c);
ierr = DMDAVecGetClosure(dm, PETSC_NULL, X, c, &x);CHKERRQ(ierr);
for(i = 0; i < cellDof; ++i) {
u[c*cellDof+i] = x[i];
}
}
for(field = 0; field < numFields; ++field) {
const PetscInt numQuadPoints = user->q[field].numQuadPoints;
const PetscInt numBasisFuncs = user->q[field].numBasisFuncs;
void (*f0)(PetscScalar u[], const PetscScalar gradU[], PetscScalar f0[]) = user->f0Funcs[field];
void (*f1)(PetscScalar u[], const PetscScalar gradU[], PetscScalar f1[]) = user->f1Funcs[field];
/* Conforming batches */
PetscInt blockSize = numBasisFuncs*numQuadPoints;
PetscInt numBlocks = 1;
PetscInt batchSize = numBlocks * blockSize;
PetscInt numBatches = user->numBatches;
PetscInt numChunks = numCells / (numBatches*batchSize);
ierr = IntegrateResidualBatchCPU(numChunks*numBatches*batchSize, numFields, field, u, invJ, detJ, user->q, f0, f1, elemVec, user);CHKERRQ(ierr);
/* Remainder */
PetscInt numRemainder = numCells % (numBatches * batchSize);
PetscInt offset = numCells - numRemainder;
ierr = IntegrateResidualBatchCPU(numRemainder, numFields, field, &u[offset*cellDof], &invJ[offset*dim*dim], &detJ[offset],
user->q, f0, f1, &elemVec[offset*cellDof], user);CHKERRQ(ierr);
}
for(c = cStart; c < cEnd; ++c) {
if (debug) {ierr = DMPrintCellVector(c, "Residual", cellDof, &elemVec[c*cellDof]);CHKERRQ(ierr);}
ierr = DMComplexVecSetClosure(dm, PETSC_NULL, F, c, &elemVec[c*cellDof], ADD_VALUES);CHKERRQ(ierr);
}
ierr = PetscFree4(u,invJ,detJ,elemVec);CHKERRQ(ierr);
ierr = PetscFree3(coords,v0,J);CHKERRQ(ierr);
if (user->showResidual) {
PetscInt p;
ierr = PetscPrintf(PETSC_COMM_WORLD, "Residual:\n");CHKERRQ(ierr);
for(p = 0; p < user->numProcs; ++p) {
if (p == user->rank) {
Vec f;
ierr = VecDuplicate(F, &f);CHKERRQ(ierr);
ierr = VecCopy(F, f);CHKERRQ(ierr);
ierr = VecChop(f, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(f, PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
ierr = VecDestroy(&f);CHKERRQ(ierr);
}
ierr = PetscBarrier((PetscObject) dm);CHKERRQ(ierr);
}
}
ierr = PetscLogEventEnd(user->residualEvent,0,0,0,0);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc, char **argv)
{
SNES snes; /* nonlinear solver */
DM dm; /* problem definition */
Vec u,r; /* solution, residual vectors */
Mat A,J; /* Jacobian matrix */
MatNullSpace nullSpace; /* May be necessary for pressure */
AppCtx user; /* user-defined work context */
JacActionCtx userJ; /* context for Jacobian MF action */
PetscInt its; /* iterations for convergence */
PetscReal error = 0.0; /* L_2 error in the solution */
PetscInt numComponents = 0, f;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL, help);CHKERRQ(ierr);
ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
ierr = SNESCreate(PETSC_COMM_WORLD, &snes);CHKERRQ(ierr);
ierr = CreateMesh(PETSC_COMM_WORLD, &user, &dm);CHKERRQ(ierr);
ierr = SNESSetDM(snes, dm);CHKERRQ(ierr);
ierr = SetupElement(dm, &user);CHKERRQ(ierr);
for (f = 0; f < NUM_FIELDS; ++f) {
PetscInt numComp;
ierr = PetscFEGetNumComponents(user.fe[f], &numComp);CHKERRQ(ierr);
numComponents += numComp;
}
ierr = PetscMalloc(NUM_FIELDS * sizeof(void (*)(const PetscReal[], PetscScalar *)), &user.exactFuncs);CHKERRQ(ierr);
user.fem.bcFuncs = (void (**)(const PetscReal[], PetscScalar *)) user.exactFuncs;
ierr = SetupExactSolution(dm, &user);CHKERRQ(ierr);
ierr = SetupSection(dm, &user);CHKERRQ(ierr);
ierr = DMPlexCreateClosureIndex(dm, NULL);CHKERRQ(ierr);
ierr = DMCreateGlobalVector(dm, &u);CHKERRQ(ierr);
ierr = VecDuplicate(u, &r);CHKERRQ(ierr);
ierr = DMSetMatType(dm,MATAIJ);CHKERRQ(ierr);
ierr = DMCreateMatrix(dm, &J);CHKERRQ(ierr);
if (user.jacobianMF) {
PetscInt M, m, N, n;
ierr = MatGetSize(J, &M, &N);CHKERRQ(ierr);
ierr = MatGetLocalSize(J, &m, &n);CHKERRQ(ierr);
ierr = MatCreate(PETSC_COMM_WORLD, &A);CHKERRQ(ierr);
ierr = MatSetSizes(A, m, n, M, N);CHKERRQ(ierr);
ierr = MatSetType(A, MATSHELL);CHKERRQ(ierr);
ierr = MatSetUp(A);CHKERRQ(ierr);
ierr = MatShellSetOperation(A, MATOP_MULT, (void (*)(void))FormJacobianAction);CHKERRQ(ierr);
userJ.dm = dm;
userJ.J = J;
userJ.user = &user;
ierr = DMCreateLocalVector(dm, &userJ.u);CHKERRQ(ierr);
ierr = DMPlexProjectFunctionLocal(dm, user.fe, user.exactFuncs, INSERT_BC_VALUES, userJ.u);CHKERRQ(ierr);
ierr = MatShellSetContext(A, &userJ);CHKERRQ(ierr);
} else {
A = J;
}
ierr = CreatePressureNullSpace(dm, &user, &nullSpace);CHKERRQ(ierr);
ierr = MatSetNullSpace(J, nullSpace);CHKERRQ(ierr);
if (A != J) {
ierr = MatSetNullSpace(A, nullSpace);CHKERRQ(ierr);
}
ierr = DMSNESSetFunctionLocal(dm, (PetscErrorCode (*)(DM,Vec,Vec,void*))DMPlexComputeResidualFEM,&user);CHKERRQ(ierr);
ierr = DMSNESSetJacobianLocal(dm, (PetscErrorCode (*)(DM,Vec,Mat,Mat,MatStructure*,void*))DMPlexComputeJacobianFEM,&user);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes, A, J, NULL, NULL);CHKERRQ(ierr);
ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
ierr = DMPlexProjectFunction(dm, user.fe, user.exactFuncs, INSERT_ALL_VALUES, u);CHKERRQ(ierr);
if (user.showInitial) {ierr = DMVecViewLocal(dm, u, PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);}
if (user.runType == RUN_FULL) {
ierr = DMPlexProjectFunction(dm, user.fe, user.initialGuess, INSERT_VALUES, u);CHKERRQ(ierr);
if (user.showInitial) {ierr = DMVecViewLocal(dm, u, PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);}
if (user.debug) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = SNESSolve(snes, NULL, u);CHKERRQ(ierr);
ierr = SNESGetIterationNumber(snes, &its);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Number of SNES iterations = %D\n", its);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(dm, user.fe, user.exactFuncs, u, &error);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %.3g\n", error);CHKERRQ(ierr);
if (user.showSolution) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Solution\n");CHKERRQ(ierr);
ierr = VecChop(u, 3.0e-9);CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
} else {
PetscReal res = 0.0;
/* Check discretization error */
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(dm, user.fe, user.exactFuncs, u, &error);CHKERRQ(ierr);
if (error >= 1.0e-11) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %g\n", error);CHKERRQ(ierr);
} else {
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: < 1.0e-11\n", error);CHKERRQ(ierr);
}
/* Check residual */
ierr = SNESComputeFunction(snes, u, r);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial Residual\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Residual: %g\n", res);CHKERRQ(ierr);
/* Check Jacobian */
{
Vec b;
MatStructure flag;
PetscBool isNull;
ierr = SNESComputeJacobian(snes, u, &A, &A, &flag);CHKERRQ(ierr);
ierr = MatNullSpaceTest(nullSpace, J, &isNull);CHKERRQ(ierr);
if (!isNull) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_PLIB, "The null space calculated for the system operator is invalid.");
ierr = VecDuplicate(u, &b);CHKERRQ(ierr);
ierr = VecSet(r, 0.0);CHKERRQ(ierr);
ierr = SNESComputeFunction(snes, r, b);CHKERRQ(ierr);
ierr = MatMult(A, u, r);CHKERRQ(ierr);
ierr = VecAXPY(r, 1.0, b);CHKERRQ(ierr);
ierr = VecDestroy(&b);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Au - b = Au + F(0)\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Linear L_2 Residual: %g\n", res);CHKERRQ(ierr);
}
}
if (user.runType == RUN_FULL) {
PetscViewer viewer;
Vec uLocal;
const char *name;
ierr = PetscViewerCreate(PETSC_COMM_WORLD, &viewer);CHKERRQ(ierr);
ierr = PetscViewerSetType(viewer, PETSCVIEWERVTK);CHKERRQ(ierr);
ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_VTK);CHKERRQ(ierr);
ierr = PetscViewerFileSetName(viewer, "ex62_sol.vtk");CHKERRQ(ierr);
ierr = DMGetLocalVector(dm, &uLocal);CHKERRQ(ierr);
ierr = PetscObjectGetName((PetscObject) u, &name);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) uLocal, name);CHKERRQ(ierr);
ierr = DMGlobalToLocalBegin(dm, u, INSERT_VALUES, uLocal);CHKERRQ(ierr);
ierr = DMGlobalToLocalEnd(dm, u, INSERT_VALUES, uLocal);CHKERRQ(ierr);
ierr = VecView(uLocal, viewer);CHKERRQ(ierr);
ierr = DMRestoreLocalVector(dm, &uLocal);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
}
ierr = PetscFree(user.exactFuncs);CHKERRQ(ierr);
ierr = DestroyElement(&user);CHKERRQ(ierr);
ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
if (user.jacobianMF) {
ierr = VecDestroy(&userJ.u);CHKERRQ(ierr);
}
if (A != J) {
ierr = MatDestroy(&A);CHKERRQ(ierr);
}
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = SNESDestroy(&snes);CHKERRQ(ierr);
ierr = DMDestroy(&dm);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
int main(int argc, char **argv)
{
SNES snes; /* nonlinear solver */
Vec u,r; /* solution, residual vectors */
Mat A,J; /* Jacobian matrix */
MatNullSpace nullSpace; /* May be necessary for pressure */
AppCtx user; /* user-defined work context */
JacActionCtx userJ; /* context for Jacobian MF action */
PetscInt its; /* iterations for convergence */
PetscReal error = 0.0; /* L_2 error in the solution */
const PetscInt numComponents = NUM_BASIS_COMPONENTS_TOTAL;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL, help);CHKERRQ(ierr);
ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
ierr = SNESCreate(PETSC_COMM_WORLD, &snes);CHKERRQ(ierr);
ierr = CreateMesh(PETSC_COMM_WORLD, &user, &user.dm);CHKERRQ(ierr);
ierr = SNESSetDM(snes, user.dm);CHKERRQ(ierr);
ierr = SetupExactSolution(user.dm, &user);CHKERRQ(ierr);
ierr = SetupQuadrature(&user);CHKERRQ(ierr);
ierr = SetupSection(user.dm, &user);CHKERRQ(ierr);
ierr = DMCreateGlobalVector(user.dm, &u);CHKERRQ(ierr);
ierr = VecDuplicate(u, &r);CHKERRQ(ierr);
ierr = DMCreateMatrix(user.dm, MATAIJ, &J);CHKERRQ(ierr);
if (user.jacobianMF) {
PetscInt M, m, N, n;
ierr = MatGetSize(J, &M, &N);CHKERRQ(ierr);
ierr = MatGetLocalSize(J, &m, &n);CHKERRQ(ierr);
ierr = MatCreate(PETSC_COMM_WORLD, &A);CHKERRQ(ierr);
ierr = MatSetSizes(A, m, n, M, N);CHKERRQ(ierr);
ierr = MatSetType(A, MATSHELL);CHKERRQ(ierr);
ierr = MatSetUp(A);CHKERRQ(ierr);
ierr = MatShellSetOperation(A, MATOP_MULT, (void (*)(void))FormJacobianAction);CHKERRQ(ierr);
userJ.dm = user.dm;
userJ.J = J;
userJ.user = &user;
ierr = DMCreateLocalVector(user.dm, &userJ.u);CHKERRQ(ierr);
ierr = DMPlexProjectFunctionLocal(user.dm, numComponents, user.exactFuncs, INSERT_BC_VALUES, userJ.u);CHKERRQ(ierr);
ierr = MatShellSetContext(A, &userJ);CHKERRQ(ierr);
} else {
A = J;
}
ierr = CreatePressureNullSpace(user.dm, &user, &nullSpace);CHKERRQ(ierr);
ierr = MatSetNullSpace(J, nullSpace);CHKERRQ(ierr);
if (A != J) {
ierr = MatSetNullSpace(A, nullSpace);CHKERRQ(ierr);
}
ierr = DMSNESSetFunctionLocal(user.dm, (PetscErrorCode (*)(DM,Vec,Vec,void*))DMPlexComputeResidualFEM,&user);CHKERRQ(ierr);
ierr = DMSNESSetJacobianLocal(user.dm, (PetscErrorCode (*)(DM,Vec,Mat,Mat,MatStructure*,void*))DMPlexComputeJacobianFEM,&user);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes, A, J, NULL, NULL);CHKERRQ(ierr);
ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
ierr = DMPlexProjectFunction(user.dm, numComponents, user.exactFuncs, INSERT_ALL_VALUES, u);CHKERRQ(ierr);
if (user.showInitial) {ierr = DMVecViewLocal(user.dm, u, PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);}
if (user.runType == RUN_FULL) {
PetscScalar (*initialGuess[numComponents])(const PetscReal x[]);
PetscInt c;
for (c = 0; c < numComponents; ++c) initialGuess[c] = zero;
ierr = DMPlexProjectFunction(user.dm, numComponents, initialGuess, INSERT_VALUES, u);CHKERRQ(ierr);
if (user.showInitial) {ierr = DMVecViewLocal(user.dm, u, PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);}
if (user.debug) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = SNESSolve(snes, NULL, u);CHKERRQ(ierr);
ierr = SNESGetIterationNumber(snes, &its);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Number of SNES iterations = %D\n", its);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(user.dm, user.fem.quad, user.exactFuncs, u, &error);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %.3g\n", error);CHKERRQ(ierr);
if (user.showSolution) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Solution\n");CHKERRQ(ierr);
ierr = VecChop(u, 3.0e-9);CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
} else {
PetscReal res = 0.0;
/* Check discretization error */
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(user.dm, user.fem.quad, user.exactFuncs, u, &error);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %g\n", error);CHKERRQ(ierr);
/* Check residual */
ierr = SNESComputeFunction(snes, u, r);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial Residual\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Residual: %g\n", res);CHKERRQ(ierr);
/* Check Jacobian */
{
Vec b;
MatStructure flag;
PetscBool isNull;
ierr = SNESComputeJacobian(snes, u, &A, &A, &flag);CHKERRQ(ierr);
ierr = MatNullSpaceTest(nullSpace, J, &isNull);CHKERRQ(ierr);
if (!isNull) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_PLIB, "The null space calculated for the system operator is invalid.");
ierr = VecDuplicate(u, &b);CHKERRQ(ierr);
ierr = VecSet(r, 0.0);CHKERRQ(ierr);
ierr = SNESComputeFunction(snes, r, b);CHKERRQ(ierr);
ierr = MatMult(A, u, r);CHKERRQ(ierr);
ierr = VecAXPY(r, 1.0, b);CHKERRQ(ierr);
ierr = VecDestroy(&b);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Au - b = Au + F(0)\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Linear L_2 Residual: %g\n", res);CHKERRQ(ierr);
}
}
if (user.runType == RUN_FULL) {
PetscViewer viewer;
Vec uLocal;
ierr = PetscViewerCreate(PETSC_COMM_WORLD, &viewer);CHKERRQ(ierr);
ierr = PetscViewerSetType(viewer, PETSCVIEWERVTK);CHKERRQ(ierr);
ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_VTK);CHKERRQ(ierr);
ierr = PetscViewerFileSetName(viewer, "ex62_sol.vtk");CHKERRQ(ierr);
ierr = DMGetLocalVector(user.dm, &uLocal);CHKERRQ(ierr);
ierr = DMGlobalToLocalBegin(user.dm, u, INSERT_VALUES, uLocal);CHKERRQ(ierr);
ierr = DMGlobalToLocalEnd(user.dm, u, INSERT_VALUES, uLocal);CHKERRQ(ierr);
ierr = PetscObjectReference((PetscObject) user.dm);CHKERRQ(ierr); /* Needed because viewer destroys the DM */
ierr = PetscObjectReference((PetscObject) uLocal);CHKERRQ(ierr); /* Needed because viewer destroys the Vec */
ierr = PetscViewerVTKAddField(viewer, (PetscObject) user.dm, DMPlexVTKWriteAll, PETSC_VTK_POINT_FIELD, (PetscObject) uLocal);CHKERRQ(ierr);
ierr = DMRestoreLocalVector(user.dm, &uLocal);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
}
ierr = DestroyQuadrature(&user);CHKERRQ(ierr);
ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
if (user.jacobianMF) {
ierr = VecDestroy(&userJ.u);CHKERRQ(ierr);
}
if (A != J) {
ierr = MatDestroy(&A);CHKERRQ(ierr);
}
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = SNESDestroy(&snes);CHKERRQ(ierr);
ierr = DMDestroy(&user.dm);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
int main(int argc, char **argv)
{
DM dm; /* Problem specification */
DM dmAux; /* Material specification */
SNES snes; /* nonlinear solver */
Vec u,r; /* solution, residual vectors */
Mat A,J; /* Jacobian matrix */
MatNullSpace nullSpace; /* May be necessary for Neumann conditions */
AppCtx user; /* user-defined work context */
JacActionCtx userJ; /* context for Jacobian MF action */
PetscInt its; /* iterations for convergence */
PetscReal error = 0.0; /* L_2 error in the solution */
PetscInt numComponents;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL, help);CHKERRQ(ierr);
ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
ierr = SNESCreate(PETSC_COMM_WORLD, &snes);CHKERRQ(ierr);
ierr = CreateMesh(PETSC_COMM_WORLD, &user, &dm);CHKERRQ(ierr);
ierr = SNESSetDM(snes, dm);CHKERRQ(ierr);
ierr = DMSetApplicationContext(dm, &user);CHKERRQ(ierr);
user.fem.fe = user.fe;
ierr = PetscFECreateDefault(dm, user.dim, 1, PETSC_TRUE, NULL, -1, &user.fe[0]);CHKERRQ(ierr);
if (user.bcType != NEUMANN) {
user.fem.feBd = NULL; user.feBd[0] = NULL;
} else {
user.fem.feBd = user.feBd;
ierr = PetscFECreateDefault(dm, user.dim-1, 1, PETSC_TRUE, "bd_", -1, &user.feBd[0]);CHKERRQ(ierr);
}
ierr = PetscFEGetNumComponents(user.fe[0], &numComponents);CHKERRQ(ierr);
ierr = PetscMalloc(NUM_FIELDS * sizeof(void (*)(const PetscReal[], PetscScalar *, void *)), &user.exactFuncs);CHKERRQ(ierr);
ierr = SetupProblem(dm, &user);CHKERRQ(ierr);
ierr = SetupSection(dm, &user);CHKERRQ(ierr);
/* Setup Material */
ierr = DMClone(dm, &dmAux);CHKERRQ(ierr);
ierr = DMPlexCopyCoordinates(dm, dmAux);CHKERRQ(ierr);
if (user.variableCoefficient != COEFF_FIELD) {
user.fem.feAux = NULL; user.feAux[0] = NULL;
} else {
PetscQuadrature q;
user.fem.feAux = user.feAux;
ierr = PetscFECreateDefault(dmAux, user.dim, 1, PETSC_TRUE, "mat_", -1, &user.feAux[0]);CHKERRQ(ierr);
ierr = PetscFEGetQuadrature(user.fe[0], &q);CHKERRQ(ierr);
ierr = PetscFESetQuadrature(user.feAux[0], q);CHKERRQ(ierr);
}
ierr = SetupMaterialSection(dmAux, &user);CHKERRQ(ierr);
ierr = SetupMaterial(dm, dmAux, &user);CHKERRQ(ierr);
ierr = DMDestroy(&dmAux);CHKERRQ(ierr);
ierr = DMCreateGlobalVector(dm, &u);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) u, "potential");CHKERRQ(ierr);
ierr = VecDuplicate(u, &r);CHKERRQ(ierr);
ierr = DMSetMatType(dm,MATAIJ);CHKERRQ(ierr);
ierr = DMCreateMatrix(dm, &J);CHKERRQ(ierr);
if (user.jacobianMF) {
PetscInt M, m, N, n;
ierr = MatGetSize(J, &M, &N);CHKERRQ(ierr);
ierr = MatGetLocalSize(J, &m, &n);CHKERRQ(ierr);
ierr = MatCreate(PETSC_COMM_WORLD, &A);CHKERRQ(ierr);
ierr = MatSetSizes(A, m, n, M, N);CHKERRQ(ierr);
ierr = MatSetType(A, MATSHELL);CHKERRQ(ierr);
ierr = MatSetUp(A);CHKERRQ(ierr);
#if 0
ierr = MatShellSetOperation(A, MATOP_MULT, (void (*)(void))FormJacobianAction);CHKERRQ(ierr);
#endif
userJ.dm = dm;
userJ.J = J;
userJ.user = &user;
ierr = DMCreateLocalVector(dm, &userJ.u);CHKERRQ(ierr);
ierr = DMPlexProjectFunctionLocal(dm, user.fe, user.exactFuncs, NULL, INSERT_BC_VALUES, userJ.u);CHKERRQ(ierr);
ierr = MatShellSetContext(A, &userJ);CHKERRQ(ierr);
} else {
A = J;
}
if (user.bcType == NEUMANN) {
ierr = MatNullSpaceCreate(PetscObjectComm((PetscObject) dm), PETSC_TRUE, 0, NULL, &nullSpace);CHKERRQ(ierr);
ierr = MatSetNullSpace(J, nullSpace);CHKERRQ(ierr);
if (A != J) {
ierr = MatSetNullSpace(A, nullSpace);CHKERRQ(ierr);
}
}
ierr = DMSNESSetFunctionLocal(dm, (PetscErrorCode (*)(DM,Vec,Vec,void*)) DMPlexComputeResidualFEM, &user);CHKERRQ(ierr);
ierr = DMSNESSetJacobianLocal(dm, (PetscErrorCode (*)(DM,Vec,Mat,Mat,void*)) DMPlexComputeJacobianFEM, &user);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes, A, J, NULL, NULL);CHKERRQ(ierr);
ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
ierr = DMPlexProjectFunction(dm, user.fe, user.exactFuncs, NULL, INSERT_ALL_VALUES, u);CHKERRQ(ierr);
if (user.checkpoint) {
#if defined(PETSC_HAVE_HDF5)
ierr = PetscViewerHDF5PushGroup(user.checkpoint, "/fields");CHKERRQ(ierr);
ierr = VecLoad(u, user.checkpoint);CHKERRQ(ierr);
ierr = PetscViewerHDF5PopGroup(user.checkpoint);CHKERRQ(ierr);
#endif
}
ierr = PetscViewerDestroy(&user.checkpoint);CHKERRQ(ierr);
if (user.showInitial) {
Vec lv;
ierr = DMGetLocalVector(dm, &lv);CHKERRQ(ierr);
ierr = DMGlobalToLocalBegin(dm, u, INSERT_VALUES, lv);CHKERRQ(ierr);
ierr = DMGlobalToLocalEnd(dm, u, INSERT_VALUES, lv);CHKERRQ(ierr);
ierr = DMPrintLocalVec(dm, "Local function", 1.0e-10, lv);CHKERRQ(ierr);
ierr = DMRestoreLocalVector(dm, &lv);CHKERRQ(ierr);
}
if (user.runType == RUN_FULL) {
void (*initialGuess[numComponents])(const PetscReal x[], PetscScalar *, void *ctx);
PetscInt c;
for (c = 0; c < numComponents; ++c) initialGuess[c] = zero;
ierr = DMPlexProjectFunction(dm, user.fe, initialGuess, NULL, INSERT_VALUES, u);CHKERRQ(ierr);
if (user.debug) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = SNESSolve(snes, NULL, u);CHKERRQ(ierr);
ierr = SNESGetIterationNumber(snes, &its);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Number of SNES iterations = %D\n", its);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(dm, user.fe, user.exactFuncs, NULL, u, &error);CHKERRQ(ierr);
if (error < 1.0e-11) {ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: < 1.0e-11\n");CHKERRQ(ierr);}
else {ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %g\n", error);CHKERRQ(ierr);}
if (user.showSolution) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "Solution\n");CHKERRQ(ierr);
ierr = VecChop(u, 3.0e-9);CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
} else if (user.runType == RUN_PERF) {
PetscReal res = 0.0;
ierr = SNESComputeFunction(snes, u, r);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial Residual\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Residual: %g\n", res);CHKERRQ(ierr);
} else {
PetscReal res = 0.0;
/* Check discretization error */
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial guess\n");CHKERRQ(ierr);
ierr = VecView(u, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = DMPlexComputeL2Diff(dm, user.fe, user.exactFuncs, NULL, u, &error);CHKERRQ(ierr);
if (error < 1.0e-11) {ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: < 1.0e-11\n");CHKERRQ(ierr);}
else {ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Error: %g\n", error);CHKERRQ(ierr);}
/* Check residual */
ierr = SNESComputeFunction(snes, u, r);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Initial Residual\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "L_2 Residual: %g\n", res);CHKERRQ(ierr);
/* Check Jacobian */
{
Vec b;
ierr = SNESComputeJacobian(snes, u, A, A);CHKERRQ(ierr);
ierr = VecDuplicate(u, &b);CHKERRQ(ierr);
ierr = VecSet(r, 0.0);CHKERRQ(ierr);
ierr = SNESComputeFunction(snes, r, b);CHKERRQ(ierr);
ierr = MatMult(A, u, r);CHKERRQ(ierr);
ierr = VecAXPY(r, 1.0, b);CHKERRQ(ierr);
ierr = VecDestroy(&b);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Au - b = Au + F(0)\n");CHKERRQ(ierr);
ierr = VecChop(r, 1.0e-10);CHKERRQ(ierr);
ierr = VecView(r, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecNorm(r, NORM_2, &res);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "Linear L_2 Residual: %g\n", res);CHKERRQ(ierr);
}
}
ierr = VecViewFromOptions(u, NULL, "-vec_view");CHKERRQ(ierr);
if (user.bcType == NEUMANN) {
ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
}
if (user.jacobianMF) {
ierr = VecDestroy(&userJ.u);CHKERRQ(ierr);
}
if (A != J) {ierr = MatDestroy(&A);CHKERRQ(ierr);}
ierr = PetscFEDestroy(&user.fe[0]);CHKERRQ(ierr);
ierr = PetscFEDestroy(&user.feBd[0]);CHKERRQ(ierr);
ierr = PetscFEDestroy(&user.feAux[0]);CHKERRQ(ierr);
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = SNESDestroy(&snes);CHKERRQ(ierr);
ierr = DMDestroy(&dm);CHKERRQ(ierr);
ierr = PetscFree(user.exactFuncs);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
static PetscErrorCode ComputeSpectral(DM dm, Vec u, PetscInt numPlanes, const PetscInt planeDir[], const PetscReal planeCoord[], AppCtx *user)
{
MPI_Comm comm;
PetscSection coordSection, section;
Vec coordinates, uloc;
const PetscScalar *coords, *array;
PetscInt p;
PetscMPIInt size, rank;
PetscErrorCode ierr;
PetscFunctionBeginUser;
ierr = PetscObjectGetComm((PetscObject) dm, &comm);CHKERRQ(ierr);
ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
ierr = DMGetLocalVector(dm, &uloc);CHKERRQ(ierr);
ierr = DMGlobalToLocalBegin(dm, u, INSERT_VALUES, uloc);CHKERRQ(ierr);
ierr = DMGlobalToLocalEnd(dm, u, INSERT_VALUES, uloc);CHKERRQ(ierr);
ierr = DMPlexInsertBoundaryValues(dm, PETSC_TRUE, uloc, 0.0, NULL, NULL, NULL);CHKERRQ(ierr);
ierr = VecViewFromOptions(uloc, NULL, "-sol_view");CHKERRQ(ierr);
ierr = DMGetDefaultSection(dm, §ion);CHKERRQ(ierr);
ierr = VecGetArrayRead(uloc, &array);CHKERRQ(ierr);
ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
ierr = DMGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
ierr = VecGetArrayRead(coordinates, &coords);CHKERRQ(ierr);
for (p = 0; p < numPlanes; ++p) {
DMLabel label;
char name[PETSC_MAX_PATH_LEN];
Mat F;
Vec x, y;
IS stratum;
PetscReal *ray, *gray;
PetscScalar *rvals, *svals, *gsvals;
PetscInt *perm, *nperm;
PetscInt n, N, i, j, off, offu;
const PetscInt *points;
ierr = PetscSNPrintf(name, PETSC_MAX_PATH_LEN, "spectral_plane_%D", p);CHKERRQ(ierr);
ierr = DMGetLabel(dm, name, &label);CHKERRQ(ierr);
ierr = DMLabelGetStratumIS(label, 1, &stratum);CHKERRQ(ierr);
ierr = ISGetLocalSize(stratum, &n);CHKERRQ(ierr);
ierr = ISGetIndices(stratum, &points);CHKERRQ(ierr);
ierr = PetscMalloc2(n, &ray, n, &svals);CHKERRQ(ierr);
for (i = 0; i < n; ++i) {
ierr = PetscSectionGetOffset(coordSection, points[i], &off);CHKERRQ(ierr);
ierr = PetscSectionGetOffset(section, points[i], &offu);CHKERRQ(ierr);
ray[i] = PetscRealPart(coords[off+((planeDir[p]+1)%2)]);
svals[i] = array[offu];
}
/* Gather the ray data to proc 0 */
if (size > 1) {
PetscMPIInt *cnt, *displs, p;
ierr = PetscCalloc2(size, &cnt, size, &displs);CHKERRQ(ierr);
ierr = MPI_Gather(&n, 1, MPIU_INT, cnt, 1, MPIU_INT, 0, comm);CHKERRQ(ierr);
for (p = 1; p < size; ++p) displs[p] = displs[p-1] + cnt[p-1];
N = displs[size-1] + cnt[size-1];
ierr = PetscMalloc2(N, &gray, N, &gsvals);CHKERRQ(ierr);
ierr = MPI_Gatherv(ray, n, MPIU_REAL, gray, cnt, displs, MPIU_REAL, 0, comm);CHKERRQ(ierr);
ierr = MPI_Gatherv(svals, n, MPIU_SCALAR, gsvals, cnt, displs, MPIU_SCALAR, 0, comm);CHKERRQ(ierr);
ierr = PetscFree2(cnt, displs);CHKERRQ(ierr);
} else {
N = n;
gray = ray;
gsvals = svals;
}
if (!rank) {
/* Sort point along ray */
ierr = PetscMalloc2(N, &perm, N, &nperm);CHKERRQ(ierr);
for (i = 0; i < N; ++i) {perm[i] = i;}
ierr = PetscSortRealWithPermutation(N, gray, perm);CHKERRQ(ierr);
/* Count duplicates and squish mapping */
nperm[0] = perm[0];
for (i = 1, j = 1; i < N; ++i) {
if (PetscAbsReal(gray[perm[i]] - gray[perm[i-1]]) > PETSC_SMALL) nperm[j++] = perm[i];
}
/* Create FFT structs */
ierr = MatCreateFFT(PETSC_COMM_SELF, 1, &j, MATFFTW, &F);CHKERRQ(ierr);
ierr = MatCreateVecs(F, &x, &y);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) y, name);CHKERRQ(ierr);
ierr = VecGetArray(x, &rvals);CHKERRQ(ierr);
for (i = 0, j = 0; i < N; ++i) {
if (i > 0 && PetscAbsReal(gray[perm[i]] - gray[perm[i-1]]) < PETSC_SMALL) continue;
rvals[j] = gsvals[nperm[j]];
++j;
}
ierr = PetscFree2(perm, nperm);CHKERRQ(ierr);
if (size > 1) {ierr = PetscFree2(gray, gsvals);CHKERRQ(ierr);}
ierr = VecRestoreArray(x, &rvals);CHKERRQ(ierr);
/* Do FFT along the ray */
ierr = MatMult(F, x, y);CHKERRQ(ierr);
/* Chop FFT */
ierr = VecChop(y, PETSC_SMALL);CHKERRQ(ierr);
ierr = VecViewFromOptions(x, NULL, "-real_view");CHKERRQ(ierr);
ierr = VecViewFromOptions(y, NULL, "-fft_view");CHKERRQ(ierr);
ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = VecDestroy(&y);CHKERRQ(ierr);
ierr = MatDestroy(&F);CHKERRQ(ierr);
}
ierr = ISRestoreIndices(stratum, &points);CHKERRQ(ierr);
ierr = ISDestroy(&stratum);CHKERRQ(ierr);
ierr = PetscFree2(ray, svals);CHKERRQ(ierr);
}
ierr = VecRestoreArrayRead(coordinates, &coords);CHKERRQ(ierr);
ierr = VecRestoreArrayRead(uloc, &array);CHKERRQ(ierr);
ierr = DMRestoreLocalVector(dm, &uloc);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL vecchop_(Vec v,PetscReal *tol, int *__ierr ){
*__ierr = VecChop(
(Vec)PetscToPointer((v) ),*tol);
}
