PetscErrorCode StokesCalcResidual(Stokes *s)
{
PetscReal val;
Vec b0, b1;
PetscErrorCode ierr;
PetscFunctionBeginUser;
/* residual Ax-b (*warning* overwrites b) */
ierr = VecScale(s->b, -1.0);CHKERRQ(ierr);
ierr = MatMultAdd(s->A, s->x, s->b, s->b);CHKERRQ(ierr);
/* ierr = VecView(s->b, (PetscViewer)PETSC_VIEWER_DEFAULT);CHKERRQ(ierr); */
/* residual velocity */
ierr = VecGetSubVector(s->b, s->isg[0], &b0);CHKERRQ(ierr);
ierr = VecNorm(b0, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," residual u = %g\n",(double)val);CHKERRQ(ierr);
ierr = VecRestoreSubVector(s->b, s->isg[0], &b0);CHKERRQ(ierr);
/* residual pressure */
ierr = VecGetSubVector(s->b, s->isg[1], &b1);CHKERRQ(ierr);
ierr = VecNorm(b1, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," residual p = %g\n",(double)val);CHKERRQ(ierr);
ierr = VecRestoreSubVector(s->b, s->isg[1], &b1);CHKERRQ(ierr);
/* total residual */
ierr = VecNorm(s->b, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," residual [u,p] = %g\n", (double)val);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PetscErrorCode StokesCalcError(Stokes *s)
{
PetscScalar scale = PetscSqrtReal((double)s->nx*s->ny);
PetscReal val;
Vec y0, y1;
PetscErrorCode ierr;
PetscFunctionBeginUser;
/* error y-x */
ierr = VecAXPY(s->y, -1.0, s->x);CHKERRQ(ierr);
/* ierr = VecView(s->y, (PetscViewer)PETSC_VIEWER_DEFAULT);CHKERRQ(ierr); */
/* error in velocity */
ierr = VecGetSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);
ierr = VecNorm(y0, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error u = %g\n",(double)(PetscRealPart(val/scale)));CHKERRQ(ierr);
ierr = VecRestoreSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);
/* error in pressure */
ierr = VecGetSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);
ierr = VecNorm(y1, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error p = %g\n",(double)(PetscRealPart(val/scale)));CHKERRQ(ierr);
ierr = VecRestoreSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);
/* total error */
ierr = VecNorm(s->y, NORM_2, &val);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error [u,p] = %g\n", (double)PetscRealPart((val/scale)));CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PetscErrorCode StokesRhs(Stokes *s)
{
PetscInt row, start, end, i, j;
PetscScalar val;
Vec b0,b1;
PetscErrorCode ierr;
PetscFunctionBeginUser;
/* velocity part */
ierr = VecGetSubVector(s->b, s->isg[0], &b0);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(b0, &start, &end);CHKERRQ(ierr);
for (row = start; row < end; row++) {
ierr = StokesGetPosition(s, row, &i, &j);CHKERRQ(ierr);
if (row < s->nx*s->ny) {
ierr = StokesRhsMomX(s, i, j, &val);CHKERRQ(ierr);
} else if (row < 2*s->nx*s->ny) {
ierr = StokesRhsMomY(s, i, j, &val);CHKERRQ(ierr);
}
ierr = VecSetValue(b0, row, val, INSERT_VALUES);CHKERRQ(ierr);
}
ierr = VecRestoreSubVector(s->b, s->isg[0], &b0);CHKERRQ(ierr);
/* pressure part */
ierr = VecGetSubVector(s->b, s->isg[1], &b1);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(b1, &start, &end);CHKERRQ(ierr);
for (row = start; row < end; row++) {
ierr = StokesGetPosition(s, row, &i, &j);CHKERRQ(ierr);
ierr = StokesRhsMass(s, i, j, &val);CHKERRQ(ierr);
ierr = VecSetValue(b1, row, val, INSERT_VALUES);CHKERRQ(ierr);
}
ierr = VecRestoreSubVector(s->b, s->isg[1], &b1);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PetscErrorCode StokesExactSolution(Stokes *s)
{
PetscInt row, start, end, i, j;
PetscScalar val;
Vec y0,y1;
PetscErrorCode ierr;
PetscFunctionBeginUser;
/* velocity part */
ierr = VecGetSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(y0, &start, &end);CHKERRQ(ierr);
for (row = start; row < end; row++) {
ierr = StokesGetPosition(s, row,&i,&j);CHKERRQ(ierr);
if (row < s->nx*s->ny) {
val = StokesExactVelocityX(j*s->hy+s->hy/2);
} else {
val = 0;
}
ierr = VecSetValue(y0, row, val, INSERT_VALUES);CHKERRQ(ierr);
}
ierr = VecRestoreSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);
/* pressure part */
ierr = VecGetSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(y1, &start, &end);CHKERRQ(ierr);
for (row = start; row < end; row++) {
ierr = StokesGetPosition(s, row, &i, &j);CHKERRQ(ierr);
val = StokesExactPressure(i*s->hx+s->hx/2);
ierr = VecSetValue(y1, row, val, INSERT_VALUES);CHKERRQ(ierr);
}
ierr = VecRestoreSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc, char *argv[])
{
MPI_Comm comm;
Vec X,Y,Z;
PetscMPIInt rank,size;
PetscInt i,rstart,rend;
PetscScalar *x;
PetscViewer viewer;
IS is0,is1;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc,&argv,0,help);if (ierr) return ierr;
comm = PETSC_COMM_WORLD;
viewer = PETSC_VIEWER_STDOUT_WORLD;
ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
ierr = VecCreate(comm,&X);CHKERRQ(ierr);
ierr = VecSetSizes(X,10,PETSC_DETERMINE);CHKERRQ(ierr);
ierr = VecSetFromOptions(X);CHKERRQ(ierr);
ierr = VecGetOwnershipRange(X,&rstart,&rend);CHKERRQ(ierr);
ierr = VecGetArray(X,&x);CHKERRQ(ierr);
for (i=0; i<rend-rstart; i++) x[i] = rstart+i;
ierr = VecRestoreArray(X,&x);CHKERRQ(ierr);
ierr = ISCreateStride(comm,(rend-rstart)/3+3*(rank>size/2),rstart,1,&is0);CHKERRQ(ierr);
ierr = ISComplement(is0,rstart,rend,&is1);CHKERRQ(ierr);
ierr = ISView(is0,viewer);CHKERRQ(ierr);
ierr = ISView(is1,viewer);CHKERRQ(ierr);
ierr = VecGetSubVector(X,is0,&Y);CHKERRQ(ierr);
ierr = VecGetSubVector(X,is1,&Z);CHKERRQ(ierr);
ierr = VecView(Y,viewer);CHKERRQ(ierr);
ierr = VecView(Z,viewer);CHKERRQ(ierr);
ierr = VecRestoreSubVector(X,is0,&Y);CHKERRQ(ierr);
ierr = VecRestoreSubVector(X,is1,&Z);CHKERRQ(ierr);
ierr = ISDestroy(&is0);CHKERRQ(ierr);
ierr = ISDestroy(&is1);CHKERRQ(ierr);
ierr = VecDestroy(&X);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
PetscErrorCode PetscSectionRestoreField_Internal(PetscSection section, PetscSection sectionGlobal, Vec v, PetscInt field, PetscInt pStart, PetscInt pEnd, IS *is, Vec *subv)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = VecRestoreSubVector(v, *is, subv);CHKERRQ(ierr);
ierr = ISDestroy(is);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
// Monitor a sub-region of the full-domain PETSc Vec object.
PetscErrorCode ProbeVolume::monitorVec(const DM &da,
const Vec &fvec,
const PetscInt &n,
const PetscReal &t)
{
PetscErrorCode ierr;
PetscFunctionBeginUser;
// grab the part of the vector that corresponds to the sub-volume
Vec svec;
ierr = VecGetSubVector(fvec, is, &svec); CHKERRQ(ierr);
if (n_sum != 0) // we accumulate the data over the time-steps
{
if (dvec == PETSC_NULL)
{
ierr = VecDuplicate(svec, &dvec); CHKERRQ(ierr);
ierr = VecSet(dvec, 0.0); CHKERRQ(ierr);
}
ierr = VecAXPY(dvec, 1.0, svec); CHKERRQ(ierr);
count++;
if (count % n_sum == 0) // output the time-averaged data
{
ierr = VecScale(dvec, 1.0 / count); CHKERRQ(ierr);
ierr = writeVec(dvec, t); CHKERRQ(ierr);
// reset for the next accumulation cycle
ierr = VecSet(dvec, 0.0); CHKERRQ(ierr);
count = 0;
}
}
else // output the time-step sub-volume data to file
{
ierr = writeVec(svec, t); CHKERRQ(ierr);
}
ierr = VecRestoreSubVector(fvec, is, &svec); CHKERRQ(ierr);
PetscFunctionReturn(0);
} // ProbeVolume::monitorVec
