Add red black solver

This commit is contained in:
Jan Eitzinger 2023-06-17 07:35:05 +02:00
parent 703531cfee
commit dde4164af3
4 changed files with 138 additions and 11 deletions

1
.gitignore vendored
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@ -30,6 +30,7 @@
*.dylib
# Executables
exe-*
*.exe
*.out
*.app

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@ -47,7 +47,7 @@ int main(int argc, char** argv)
computeFG(&solver);
computeRHS(&solver);
if (nt % 100 == 0) normalizePressure(&solver);
solve(&solver);
solveRB(&solver);
adaptUV(&solver);
t += solver.dt;
nt++;

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@ -185,6 +185,130 @@ void solve(Solver* solver)
#endif
}
void solveRB(Solver* solver)
{
int imax = solver->imax;
int jmax = solver->jmax;
double eps = solver->eps;
int itermax = solver->itermax;
double dx2 = solver->dx * solver->dx;
double dy2 = solver->dy * solver->dy;
double idx2 = 1.0 / dx2;
double idy2 = 1.0 / dy2;
double factor = solver->omega * 0.5 * (dx2 * dy2) / (dx2 + dy2);
double* p = solver->p;
double* rhs = solver->rhs;
double epssq = eps * eps;
int it = 0;
double res = 1.0;
int pass, jsw, isw;
while ((res >= epssq) && (it < itermax)) {
res = 0.0;
jsw = 1;
for (pass = 0; pass < 2; pass++) {
isw = jsw;
for (int j = 1; j < jmax + 1; j++) {
for (int i = isw; i < imax + 1; i += 2) {
double r = RHS(i, j) -
((P(i + 1, j) - 2.0 * P(i, j) + P(i - 1, j)) * idx2 +
(P(i, j + 1) - 2.0 * P(i, j) + P(i, j - 1)) * idy2);
P(i, j) -= (factor * r);
res += (r * r);
}
isw = 3 - isw;
}
jsw = 3 - jsw;
}
for (int i = 1; i < imax + 1; i++) {
P(i, 0) = P(i, 1);
P(i, jmax + 1) = P(i, jmax);
}
for (int j = 1; j < jmax + 1; j++) {
P(0, j) = P(1, j);
P(imax + 1, j) = P(imax, j);
}
res = res / (double)(imax * jmax);
#ifdef DEBUG
printf("%d Residuum: %e\n", it, res);
#endif
it++;
}
#ifdef VERBOSE
printf("Solver took %d iterations to reach %f\n", it, sqrt(res));
#endif
}
void solveRBA(Solver* solver)
{
int imax = solver->imax;
int jmax = solver->jmax;
double eps = solver->eps;
int itermax = solver->itermax;
double dx2 = solver->dx * solver->dx;
double dy2 = solver->dy * solver->dy;
double idx2 = 1.0 / dx2;
double idy2 = 1.0 / dy2;
double factor = 0.5 * (dx2 * dy2) / (dx2 + dy2);
double omega = solver->omega;
double* p = solver->p;
double* rhs = solver->rhs;
double epssq = eps * eps;
int it = 0;
double anorm = 1.0, anormf = 0.0;
int pass, jsw, isw;
while ((anorm >= eps * anormf) && (it < itermax)) {
anorm = 0.0;
jsw = 1;
for (pass = 0; pass < 2; pass++) {
isw = jsw;
for (int j = 1; j < jmax + 1; j++) {
for (int i = isw; i < imax + 1; i += 2) {
double r = RHS(i, j) -
((P(i + 1, j) - 2.0 * P(i, j) + P(i - 1, j)) * idx2 +
(P(i, j + 1) - 2.0 * P(i, j) + P(i, j - 1)) * idy2);
anorm += fabs(r);
P(i, j) -= (omega * factor * r);
}
isw = 3 - isw;
}
jsw = 3 - jsw;
}
for (int i = 1; i < imax + 1; i++) {
P(i, 0) = P(i, 1);
P(i, jmax + 1) = P(i, jmax);
}
for (int j = 1; j < jmax + 1; j++) {
P(0, j) = P(1, j);
P(imax + 1, j) = P(imax, j);
}
#ifdef DEBUG
printf("%d Residuum: %e\n", it, res);
#endif
it++;
}
#ifdef VERBOSE
printf("Solver took %d iterations to reach %f\n", it, anorm);
#endif
}
static double maxElement(Solver* solver, double* m)
{
int size = (solver->imax + 2) * (solver->jmax + 2);

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@ -31,14 +31,16 @@ typedef struct {
int bcLeft, bcRight, bcBottom, bcTop;
} Solver;
void initSolver(Solver*, Parameter*);
void computeRHS(Solver*);
void solve(Solver*);
void normalizePressure(Solver*);
void computeTimestep(Solver*);
void setBoundaryConditions(Solver*);
void setSpecialBoundaryCondition(Solver*);
void computeFG(Solver*);
void adaptUV(Solver*);
void writeResult(Solver*);
extern void initSolver(Solver*, Parameter*);
extern void computeRHS(Solver*);
extern void solve(Solver*);
extern void solveRB(Solver*);
extern void solveRBA(Solver*);
extern void normalizePressure(Solver*);
extern void computeTimestep(Solver*);
extern void setBoundaryConditions(Solver*);
extern void setSpecialBoundaryCondition(Solver*);
extern void computeFG(Solver*);
extern void adaptUV(Solver*);
extern void writeResult(Solver*);
#endif