2D-MPI Multigrid complete and tested

BasicSolver/2D-seq-multigrid/backstep.par

@@ -44,6 +44,7 @@ eps      0.0001   # stopping tolerance for pressure iteration
 rho      0.52
 omg      1.8       # relaxation parameter for SOR iteration
 gamma    0.9       # upwind differencing factor gamma
+levels   5         # Multigrid levels
 
 # Particle Tracing Data:
 # -----------------------

BasicSolver/2D-seq-multigrid/canal.par

@@ -26,8 +26,8 @@ p_init    1.0      # initial value for pressure
 
 xlength    30.0     # domain size in x-direction
 ylength    4.0	   # domain size in y-direction
-imax       200      # number of interior cells in x-direction
-jmax       50	   # number of interior cells in y-direction
+imax       1200      # number of interior cells in x-direction
+jmax       160	   # number of interior cells in y-direction
 
 # Time Data:
 # ---------

BasicSolver/2D-seq-multigrid/src/solver.c

@@ -680,9 +680,10 @@ double smoothRB(Solver* solver)
 void multiGrid(Solver* solver)
 {
     double res = 0.0;
-    int imax = solver->imax;
-    int jmax = solver->jmax;
-    if (solver->currentlevel == (solver->levels - 1)) {
+    int imax   = solver->imax;
+    int jmax   = solver->jmax;
+    if (solver->currentlevel == (solver->levels - 1) ||
+        (solver->imax <= 40 || solver->jmax <= 40)) {
         for (int i = 0; i < 5; i++) {
             smoothRB(solver);
         }
@@ -692,18 +693,7 @@ void multiGrid(Solver* solver)
     for (int i = 0; i < 5; i++) {
         smoothRB(solver);
         if (solver->currentlevel == 0) {
-
-            double* p = solver->p;
-
-            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);
-            }
+            setPressureBoundaryCondition(solver);
         }
     }
     Solver coarseSolver = copySolver(solver);
@@ -726,46 +716,26 @@ void multiGrid(Solver* solver)
     correct(solver);
 
     if (solver->currentlevel == 0) {
-
-        double* p = solver->p;
-
-        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);
-        }
+        setPressureBoundaryCondition(solver);
     }
 
     for (int i = 0; i < 5; i++) {
         res = smoothRB(solver);
         if (solver->currentlevel == 0) {
-
-            double* p = solver->p;
-
-            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);
-            }
+            setPressureBoundaryCondition(solver);
         }
     }
-    #ifdef VERBOSE
-        if (solver->currentlevel == 0) {printf("Residuum: %.6f\n", res); }
+#ifdef VERBOSE
+    if (solver->currentlevel == 0) {
+        printf("Residuum: %.6f\n", res);
+    }
 #endif
 }
 
 void restrictMG(Solver* solver)
 {
-    int imax     = solver->imax;
-    int jmax     = solver->jmax;
+    int imax     = solver->imax / 2;
+    int jmax     = solver->jmax / 2;
     double* r    = solver->r[solver->currentlevel + 1];
     double* oldr = solver->r[solver->currentlevel];
 
@@ -892,3 +862,19 @@ void writeResult(Solver* solver)
 
     fclose(fp);
 }
+
+void setPressureBoundaryCondition(Solver* solver)
+{
+    double* p     = solver->p;
+    int imax = solver->imax;
+    int jmax = solver->jmax;
+    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);
+    }
+}

BasicSolver/2D-seq-multigrid/src/solver.h

@@ -59,6 +59,7 @@ extern void computeTimestep(Solver*);
 extern void setBoundaryConditions(Solver*);
 extern void setSpecialBoundaryCondition(Solver*);
 extern void setObjectBoundaryCondition(Solver*);
+extern void setPressureBoundaryCondition(Solver*);
 extern void computeFG(Solver*);
 extern void adaptUV(Solver*);
 extern void writeResult(Solver*);