/**
* The main operation reads the configuration file, initializes the scenario and
* contains the main loop. So here are the individual steps of the algorithm:
*
* - read the program configuration file using read_parameters()
* - set up the matrices (arrays) needed using the matrix() command
* - create the initial setup init_uvp(), init_flag(), output_uvp()
* - perform the main loop
* - trailer: destroy memory allocated and do some statistics
*
* The layout of the grid is described by the first figure below, the enumeration
* of the whole grid is given by the second figure. All the unknowns correspond
* to a two dimensional degree of freedom layout, so they are not stored in
* arrays, but in a matrix.
*
* @image html grid.jpg
*
* @image html whole-grid.jpg
*
* Within the main loop the following big steps are done (for some of the
* operations a definition is defined already within uvp.h):
*
* - calculate_dt() Determine the maximal time step size.
* - boundaryvalues() Set the boundary values for the next time step.
* - calculate_fg() Determine the values of F and G (diffusion and confection).
* This is the right hand side of the pressure equation and used later on for
* the time step transition.
* - calculate_rs()
* - Iterate the pressure poisson equation until the residual becomes smaller
* than eps or the maximal number of iterations is performed. Within the
* iteration loop the operation sor() is used.
* - calculate_uv() Calculate the velocity at the next time step.
*/
int main(int argn, char** args){
double Re,UI,VI,PI,GX,GY, /* problem dependent quantities */
xlength,ylength,dx,dy, /* geometry data */
t=0,t_end,dt,tau,dt_value, /* time stepping data */
alpha,omg,eps,res; /* pressure iteration data */
int it, itermax, n=0, imax, jmax; /* max iterations, iteration step and # of interior cells */
double **U, **V, **F, **G, **P, **RS;
/* Read the problem parameters */
read_parameters("data/cavity100-2.dat", &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy,
&imax, &jmax, &alpha, &omg, &tau, &itermax, &eps, &dt_value);
/* Allocate space for matrices */
U = matrix(0, imax, 0, jmax+1);
F = matrix(0, imax, 0, jmax+1);
V = matrix(0, imax+1, 0, jmax);
G = matrix(0, imax+1, 0, jmax);
P = matrix(0, imax+1, 0, jmax+1);
RS= matrix(0, imax+1, 0, jmax+1);
/* Assign initial values to u, v, p */
init_uvp(UI, VI, PI, imax, jmax, U, V, P);
while (t < t_end){
/* Select δt according to (14) */
calculate_dt(Re, tau, &dt, dx, dy, imax, jmax, U, V);
/* Set boundary values for u and v according to (15),(16) */
boundaryvalues(imax, jmax, U, V);
/* Compute F (n) and G (n) according to (10),(11),(18) */
calculate_fg(Re, GX, GY, alpha, dt, dx, dy, imax, jmax, U, V, F, G);
/* Compute the right-hand side rs of the pressure equation (12) */
calculate_rs(dt, dx, dy, imax, jmax, F, G, RS);
it = 0; res=DBL_MAX;
while (it < itermax && res > eps){
/* Perform a SOR iteration according to (19) using the provided function and retrieve the residual res */
sor(omg, dx, dy, imax, jmax, P, RS, &res);
it++;
}
/* Compute u (n+1) and v (n+1) according to (8),(9) */
calculate_uv(dt,dx,dy,imax,jmax,U,V,F,G,P);
t+=dt; n++;
}
/* Output of u, v, p for visualization */
write_vtkFile("visualization/cavity", n, xlength, ylength, imax, jmax, dx, dy, U, V, P);
/* Freeing memory */
free_matrix(U, 0, imax, 0, jmax+1);
free_matrix(F, 0, imax, 0, jmax+1);
free_matrix(V, 0, imax+1, 0, jmax);
free_matrix(G, 0, imax+1, 0, jmax);
free_matrix(P, 0, imax+1, 0, jmax+1);
free_matrix(RS, 0, imax+1, 0, jmax+1);
return -1;
}
int main(int argc, char** args){
double Re, UI, VI, PI, GX, GY, t_end, xlength, ylength, dt, dx, dy, alpha, omg, tau, eps, dt_value, t, res, dp, nu;
double **U, **V, **P, **F, **G, **RS;
double **K, **E; /* turbulent kinetic energy k, dissipation rate epsilon*/
double Fu, Fv; /* force integration variables */
double KI, EI, cn, ce, c1, c2; /* K and E: Initial values for k and epsilon */
int n, it, imax, jmax, itermax, pb, boundaries[4];
int fluid_cells; /* Number of fluid cells in our geometry */
int **Flag; /* Flagflield matrix */
char vtkname[200];
char pgm[200];
char problem[10]; /* Problem name */
char fname[200];
if(argc<2){
printf("No parameter file specified. Terminating...\n");
exit(1);
}
sprintf(fname, "%s%s", CONFIGS_FOLDER, args[1]);
printf("%s\n",fname);
read_parameters(fname, &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy, &imax, &jmax, &alpha, &omg, &itermax, &eps, boundaries, &dp, &pb, &KI, &EI, &cn, &ce, &c1, &c2, pgm, &nu, problem);
/* Allocate Flag matrix */
Flag = imatrix( 0, imax+1, 0, jmax+1 );
U = matrix ( 0 , imax+1 , 0 , jmax+1 );
V = matrix ( 0 , imax+1 , 0 , jmax+1 );
P = matrix ( 0 , imax+1 , 0 , jmax+1 );
F = matrix ( 0 , imax , 0 , jmax );
G = matrix ( 0 , imax , 0 , jmax );
RS = matrix ( 0 , imax , 0 , jmax );
K = matrix ( 0 , imax+1 , 0 , jmax+1 );
E = matrix ( 0 , imax+1 , 0 , jmax+1 );
/* Initialize values to the Flag, u, v and p */
init_flag(CONFIGS_FOLDER,pgm, imax, jmax, &fluid_cells, Flag );
init_uvp(UI, VI, PI, KI, EI, imax, jmax, U, V, P, K, E, Flag, problem );
printf("Problem: %s\n", problem );
printf( "xlength = %f, ylength = %f\n", xlength, ylength );
printf( "imax = %d, jmax = %d\n", imax, jmax );
printf( "dt = %f, dx = %f, dy = %f\n", dt, dx, dy);
printf( "Number of fluid cells = %d\n", fluid_cells );
printf( "Reynolds number: %f\n\n", Re);
t=.0;
n=0;
while( t <= t_end ){
boundaryvalues( imax, jmax, U, V, K, E, boundaries, Flag );
/* special inflow boundaries, including k and eps */
spec_boundary_val( problem, imax, jmax, U, V, K, E, Re, dp, cn, ylength);
/* calculate new values for k and eps */
comp_KAEP(Re, nu, cn, ce, c1, c2, alpha, dt, dx, dy, imax, jmax, U, V, K, E, GX, GY, Flag);
/* calculate new values for F and G */
calculate_fg( Re, GX, GY, alpha, dt, dx, dy, imax, jmax, U, V, F, G, K, E, nu, cn, Flag );
/* calculate right hand side */
calculate_rs( dt, dx, dy, imax, jmax, F, G, RS, Flag );
it = 0;
res = 10000.0;
while( it < itermax && fabs(res) > eps ){
sor( omg, dx, dy, imax, jmax, fluid_cells, P, RS, Flag, &res, problem, dp );
it++;
}
printf("[%5d: %f] dt: %f, sor iterations: %4d \n", n, t, dt, it);
/* calculate new values for u and v */
calculate_uv( dt, dx, dy, imax, jmax, U, V, F, G, P, Flag );
t += dt;
n++;
}
sprintf(vtkname, "%s%s", VISUA_FOLDER, args[1]);
write_vtkFile( vtkname, 1, xlength, ylength, imax, jmax, dx, dy, U, V, P, K, E, Flag);
comp_surface_force( Re, dx, dy, imax, jmax, U, V, P, Flag, &Fu, &Fv);
printf( "\nProblem: %s\n", problem );
printf( "xlength = %f, ylength = %f\n", xlength, ylength );
printf( "imax = %d, jmax = %d\n", imax, jmax );
printf( "dt = %f, dx = %f, dy = %f\n", dt, dx, dy);
printf( "Number of fluid cells = %d\n", fluid_cells );
printf( "Reynolds number: %f\n", Re);
printf( "Drag force = %f Lift force = %f\n", Fu, Fv);
/* free memory */
free_matrix(U,0,imax+1,0,jmax+1);
free_matrix(V,0,imax+1,0,jmax+1);
free_matrix(P,0,imax+1,0,jmax+1);
free_matrix(K,0,imax+1,0,jmax+1);
free_matrix(E,0,imax+1,0,jmax+1);
free_matrix(F,0,imax,0,jmax);
free_matrix(G,0,imax,0,jmax);
free_matrix(RS,0,imax,0,jmax);
free_imatrix(Flag,0,imax+1,0,jmax+1);
return 0;
}
int main(int argn, char** args){
if (argn !=2 ) {
printf("When running the simulation, please give a valid scenario file name!\n");
return 1;
}
//set the scenario
char *filename = NULL;
filename = args[1];
//initialize variables
double t = 0; /*time start*/
int it, n = 0; /*iteration and time step counter*/
double res; /*residual for SOR*/
/*arrays*/
double **U, **V, **P;
double **RS, **F, **G;
int **Flag; //additional data structure for arbitrary geometry
/*those to be read in from the input file*/
double Re, UI, VI, PI, GX, GY, t_end, xlength, ylength, dt, dx, dy, alpha, omg, tau, eps, dt_value;
int imax, jmax, itermax;
double presLeft, presRight, presDelta; //for pressure stuff
int wl, wr, wt, wb;
char problem[32];
double vel; //in case of a given inflow or wall velocity
//read the parameters, using problem.dat, including wl, wr, wt, wb
read_parameters(filename, &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy, &imax,
&jmax, &alpha, &omg, &tau, &itermax, &eps, &dt_value, &wl, &wr, &wt, &wb, problem, &presLeft, &presRight, &presDelta, &vel);
int pics = dt_value/dt; //just a helping variable for outputing vtk
//allocate memory, including Flag
U = matrix(0, imax+1, 0, jmax+1);
V = matrix(0, imax+1, 0, jmax+1);
P = matrix(0, imax+1, 0, jmax+1);
RS = matrix(1, imax, 1, jmax);
F = matrix(0, imax, 1, jmax);
G = matrix(1, imax, 0, jmax);
Flag = imatrix(0, imax+1, 0, jmax+1); // or Flag = imatrix(1, imax, 1, jmax);
int kmax = 20; //test no slip boundary value function
double ***U3d = (double ***) malloc((size_t)((imax+1)*(jmax+1)*(kmax+1) * sizeof(double*)) ); //test no slip boundary value function
double ***V3d = (double ***) malloc((size_t)((imax+1)*(jmax+1)*(kmax+1) * sizeof(double*)) ); //test no slip boundary value function
double ***W3d = (double ***) malloc((size_t)((imax+1)*(jmax+1)*(kmax+1) * sizeof(double*)) ); //test no slip boundary value function
int ***Flag3d = (int ***) malloc((size_t)((imax+1)*(jmax+1)*(kmax+1) * sizeof(int*)) ); //test no slip boundary value function
//initialisation, including **Flag
init_flag(problem, imax, jmax, presDelta, Flag);
init_uvp(UI, VI, PI, imax, jmax, U, V, P, problem);
//going through all time steps
while(t < t_end){
//adaptive time stepping
calculate_dt(Re, tau, &dt, dx, dy, imax, jmax, U, V);
//setting bound.values
boundaryvalues(imax, jmax, U, V, P, wl, wr, wt, wb, F, G, problem, Flag, vel); //including P, wl, wr, wt, wb, F, G, problem
//test no slip boundary value function
for(int i=1; i<=imax; i++){
for(int j=1; j<=jmax; j++){
for(int k=1; k<=kmax; k++){
boundaryvalues_no_slip(i, j, k, U3d, V3d, W3d, Flag3d); //test no slip boundary value function
}
}
}
//computing F, G and right hand side of pressue eq.
calculate_fg(Re, GX, GY, alpha, dt, dx, dy, imax, jmax, U, V, F, G, Flag);
calculate_rs(dt, dx, dy, imax, jmax, F, G, RS);
//iteration counter
it = 0;
do{
//
//perform SOR iteration, at same time set bound.values for P and new residual value
sor(omg, dx, dy, imax, jmax, P, RS, &res, Flag, presLeft, presRight);
it++;
}while(it<itermax && res>eps);
/* if (it == itermax) {
printf("Warning: sor while loop exits because it reaches the itermax. res = %f, time =%f\n", res, t);
}
*/ //calculate U and V of this time step
calculate_uv(dt, dx, dy, imax, jmax, U, V, F, G, P, Flag);
//indent time and number of time steps
n++;
t += dt;
//output of pics for animation
if (n%pics==0 ){
write_vtkFile(filename, n, xlength, ylength, imax, jmax, dx, dy, U, V, P);
}
}
//output of U, V, P at the end for visualization
//write_vtkFile("DrivenCavity", n, xlength, ylength, imax, jmax, dx, dy, U, V, P);
//free memory
free_matrix(U, 0, imax+1, 0, jmax+1);
free_matrix(V, 0, imax+1, 0, jmax+1);
free_matrix(P, 0, imax+1, 0, jmax+1);
free_matrix(RS, 1, imax, 1, jmax);
free_matrix(F, 0, imax, 1, jmax);
free_matrix(G, 1, imax, 0, jmax);
free_imatrix(Flag, 0, imax+1, 0, jmax+1);
free(U3d);
free(V3d);
free(W3d);
free(Flag3d);
return -1;
}
int main(int argn, char** args){
double **U, **V, **P, **F, **G, **RS;
const char *szFileName = "dam_break.dat";
double Re, UI, VI, PI, GX, GY, t_end, xlength, ylength, dt, dx, dy, alpha, omg, tau, eps, dt_value;
double res = 0, t = 0, n = 0;
int imax, jmax, itermax, it;
/* Additional data structures for VOF */
double **fluidFraction;
double **fluidFraction_alt;
int **flagField;
double **dFdx, **dFdy;
int **pic;
char output_dirname[60];
double epsilon = 1e-10;
/* Read the program configuration file using read_parameters() */
read_parameters(szFileName, &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy, &imax, &jmax, &alpha, &omg, &tau, &itermax, &eps, &dt_value);
/* Set up the matrices (arrays) needed using the matrix() command */
U = matrix(0, imax , 0, jmax+1);
V = matrix(0, imax+1, 0, jmax );
P = matrix(0, imax+1, 0, jmax+1);
F = matrix(0, imax , 0, jmax+1);
G = matrix(0, imax+1, 0, jmax );
RS= matrix(0, imax+1, 0, jmax+1);
flagField = imatrix(0, imax+1, 0, jmax+1);
fluidFraction = matrix(0, imax+1, 0, jmax+1);
fluidFraction_alt = matrix(0, imax+1, 0, jmax+1);
dFdx = matrix(0, imax+1, 0, jmax+1);
dFdy = matrix(0, imax+1, 0, jmax+1);
/*create a directory*/
strcpy(output_dirname, "dam_break/dam_break");
mkdir("dam_break", 0777);
/* Read pgm file with domain and initial setting */
pic = read_pgm("dam_break.pgm");
init_fluidFraction(pic, fluidFraction,fluidFraction_alt, imax, jmax);
/* Assign initial values to u, v, p */
init_uvp(UI, VI, PI, imax, jmax, U, V, P);
/* Set valid values for the fluid fraction */
adjust_fluidFraction(fluidFraction, flagField, epsilon, imax, jmax);
while(t <= t_end){
/*Select δt*/
calculate_dt(Re, tau, &dt, dx, dy, imax, jmax, U, V);
/* Set boundary values for u and v */
/* boundaryvalues(imax, jmax, U, V, flagField, dx, dy);
*/
/* Compute F(n) and G(n) */
calculate_fg(Re, GX, GY, alpha, dt, dx, dy, imax, jmax, U, V, F, G, flagField);
/* Compute the right-hand side rs of the pressure equation */
calculate_rs(dt, dx, dy, imax, jmax, F, G, RS, flagField);
/* Determine the orientation of the free surfaces */
calculate_freeSurfaceOrientation(fluidFraction, flagField, dFdx, dFdy, dx, dy, imax, jmax);
/* Perform SOR iterations */
it=0;
res = 1e6;
while(it < itermax && res > eps){
sor(omg, dx, dy, imax, jmax, P, RS, fluidFraction, flagField, dFdx, dFdy, &res);
it++;
}
/* Compute u(n+1) and v(n+1) */
calculate_uv(dt, dx, dy, imax, jmax, U, V, F, G, P, flagField);
boundaryvalues(imax, jmax, U, V, flagField, dx, dy);
/* Compute fluidFraction(n+1) */
calculate_fluidFraction(fluidFraction,fluidFraction_alt, flagField, U, V, dFdx, dFdy, imax, jmax, dx, dy, dt);
boundaryvalues(imax, jmax, U, V, flagField, dx, dy);
/* Set valid values for the fluid fraction */
adjust_fluidFraction(fluidFraction, flagField, epsilon, imax, jmax);
boundaryvalues(imax, jmax, U, V, flagField, dx, dy);
if((int)n % 10 == 0) {
write_vtkFile(output_dirname, n, xlength, ylength, imax, jmax, dx, dy, U, V, P, fluidFraction, flagField);
}
/* Print out simulation time and whether SOR converged */
printf("Time: %.4f", t);
if(res > eps) {printf("\t*** Did not converge (res=%f, eps=%f)", res, eps);return -1;}
printf("\n");
t = t + dt;
n++;
}
free_matrix(U , 0, imax , 0, jmax+1);
free_matrix(V , 0, imax+1, 0, jmax );
free_matrix(P , 0, imax+1, 0, jmax+1);
free_matrix(F , 0, imax , 0, jmax+1);
free_matrix(G , 0, imax+1, 0, jmax );
free_matrix(RS, 0, imax+1, 0, jmax+1);
return -1;
}
int main(int argn, char** args){
double **U, **V, **P, **F, **G, **RS;
int **Flag;
char problem[60];
char parameters_filename[60];
char pgm[60];
char output_dirname[60];
double Re, UI, VI, PI, GX, GY, t_end, xlength, ylength, dt, dx, dy, alpha, omg, tau, eps, dt_value, dp;
double res = 0, t = 0, n = 0;
int imax, jmax, itermax, it;
int wl, wr, wt, wb;
int timestepsPerPlotting;
char old_output_filename[128];
struct dirent *old_outputfile;
DIR *output_dir;
/* Variables for parallel program */
int iproc, jproc, myrank, il, ir, jb, jt, rank_l, rank_r, rank_b, rank_t, omg_i, omg_j, num_proc;
double min_dt;
double *bufSend, *bufRecv;
double totalTime = 0;
struct timespec previousTime, currentTime;
MPI_Init(&argn, &args);
MPI_Comm_size(MPI_COMM_WORLD, &num_proc);
/* Read name of the problem from the command line arguments */
if(argn > 1) {
strcpy(problem, args[1]);
} else {
printf("\n=== ERROR: Please provide the name of the problem\n=== e.g. Run ./sim problem_name if there is a problem_name.dat file.\n\n");
MPI_Finalize();
return 1;
}
/* Generate input filename based on problem name */
strcpy(parameters_filename, problem);
strcat(parameters_filename, ".dat");
/* Read the program configuration file using read_parameters() */
read_parameters(parameters_filename, pgm, &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy, &imax, &jmax, &alpha, &omg, &tau, &itermax, &eps, &dt_value, problem, &dp, &wl, &wr, &wt, &wb, ×tepsPerPlotting, &iproc, &jproc);
printf("%s\n", pgm);
/* Check if the number of processes is correct */
if(iproc * jproc != num_proc) {
printf("\n=== ERROR: Number of processes is incorrect (iproc=%d, jproc=%d, -np=%d) ===\n\n", iproc, jproc, num_proc);
MPI_Finalize();
return 1;
}
/* Create folder with the name of the problem */
strcpy(output_dirname, problem);
strcat(output_dirname, "/");
strcat(output_dirname, problem);
mkdir(problem, 0777);
output_dir = opendir(problem);
/* Delete existing files in output folder*/
while((old_outputfile = readdir(output_dir))) {
sprintf(old_output_filename, "%s/%s", problem, old_outputfile->d_name);
remove(old_output_filename);
}
/* Determine subdomain and neighbours for each process */
init_parallel(iproc, jproc, imax, jmax, &myrank, &il, &ir, &jb, &jt, &rank_l, &rank_r, &rank_b, &rank_t, &omg_i, &omg_j, num_proc);
/* Set up the matrices (arrays) needed using the matrix() command */
U = matrix(il-2, ir+1, jb-1, jt+1);
V = matrix(il-1, ir+1, jb-2, jt+1);
P = matrix(il-1, ir+1, jb-1, jt+1);
F = matrix(il-2, ir+1, jb-1, jt+1);
G = matrix(il-1, ir+1, jb-2, jt+1);
RS= matrix(il, ir, jb, jt);
Flag = imatrix(il-1, ir+1, jb-1, jt+1);
/* Assign initial values to u, v, p */
init_uvp(UI, VI, PI, il, ir, jb, jt, U, V, P);
/* Allocate memory for buffers */
bufSend = malloc(max(ir-il+3, jt-jb+3) * sizeof(double));
bufRecv = malloc(max(ir-il+3, jt-jb+3) * sizeof(double));
/* Initialize lower part of the domain with UI = 0 for the flow_over_step problem */
/* (this code might be moved to somewhere else later) */
if(strcmp(problem, "flow_over_step") == 0) {
init_matrix(U, il, ir, jb, min(jmax/2, jt), 0);
}
/* Initialization of flag field */
init_flag(pgm, imax, jmax, il, ir, jb, jt, Flag, dp);
if(myrank == 0) {
clock_gettime(CLOCK_MONOTONIC, ¤tTime);
}
while(t <= t_end){
/* Select δt */
calculate_dt(Re, tau, &dt, dx, dy, il, ir, jb, jt, U, V);
MPI_Allreduce(&dt, &min_dt, 1, MPI_DOUBLE, MPI_MIN, MPI_COMM_WORLD);
dt = min_dt;
/* Set boundary values for u and v */
boundaryvalues(il, ir, jb, jt, imax, jmax, U, V, wl, wr, wt, wb, Flag);
/* Set special boundary values */
spec_boundary_val(problem, il, ir, jb, jt, imax, jmax, U, V, P, Re, xlength, ylength, dp);
/* Compute F(n) and G(n) */
calculate_fg(Re, GX, GY, alpha, dt, dx, dy, il, ir, jb, jt, imax, jmax, U, V, F, G, Flag);
/* Compute the right-hand side rs of the pressure equation */
calculate_rs(dt, dx, dy, il, ir, jb, jt, imax, jmax, F, G, RS);
/* Perform SOR iterations */
it = 0;
res = 1e6;
while(it < itermax && res > eps){
sor(omg, dx, dy, dp, il, ir, jb, jt, imax, jmax, rank_l, rank_r, rank_b, rank_t, P, RS, &res, Flag, bufSend, bufRecv);
it++;
}
/* Compute u(n+1) and v(n+1) */
calculate_uv(dt, dx, dy, il, ir, jb, jt, imax, jmax, U, V, F, G, P, Flag);
/* Exchange velocity strips */
uv_com(U, V, il, ir, jb, jt, rank_l, rank_r, rank_b, rank_t, bufSend, bufRecv);
t = t + dt;
n++;
/* Generate snapshot for current timestep */
if((int) n % timestepsPerPlotting == 0) {
write_vtkFile(output_dirname, myrank, n, xlength, ylength, il, ir, jb, jt, imax, jmax, dx, dy, U, V, P);
}
/* Print out simulation time and whether the SOR converged */
if(myrank == 0) {
/* Print simulation time */
printf("Time: %.4f", t);
/* Print runtime */
previousTime = currentTime;
clock_gettime(CLOCK_MONOTONIC, ¤tTime);
totalTime += (double)currentTime.tv_sec + 1e-9 * currentTime.tv_nsec - (double)previousTime.tv_sec - 1e-9 * previousTime.tv_nsec;
printf("\tRuntime: %.3f s (avg runtime/step: %.3f s)", totalTime, totalTime/n);
if(res > eps) printf("\tDid not converge (res=%f, eps=%f)", res, eps);
printf("\n");
}
}
/* Close the output folder */
closedir(output_dir);
/* Tell user where to find the output */
if(myrank == 0) {
printf("Please find the output in the folder \"%s\".\n", problem);
}
/* Free allocated memory */
free_matrix(U, il-2, ir+1, jb-1, jt+1);
free_matrix(V, il-1, ir+1, jb-2, jt+1);
free_matrix(P, il-1, ir+1, jb-1, jt+1);
free_matrix(F, il-2, ir+1, jb-1, jt+1);
free_matrix(G, il-1, ir+1, jb-2, jt+1);
free_matrix(RS, il, ir, jb, jt);
free_imatrix(Flag, il-1, ir+1, jb-1, jt+1);
free(bufSend);
free(bufRecv);
MPI_Barrier(MPI_COMM_WORLD);
MPI_Finalize();
return 0;
}
/**
* The main operation reads the configuration file, initializes the scenario and
* contains the main loop. So here are the individual steps of the algorithm:
*
* - read the program configuration file using read_parameters()
* - set up the matrices (arrays) needed using the matrix() command
* - create the initial setup init_uvp(), init_flag(), output_uvp()
* - perform the main loop
* - trailer: destroy memory allocated and do some statistics
*
* The layout of the grid is decribed by the first figure below, the enumeration
* of the whole grid is given by the second figure. All the unknowns corresond
* to a two dimensional degree of freedom layout, so they are not stored in
* arrays, but in a matrix.
*
* @image html grid.jpg
*
* @image html whole-grid.jpg
*
* Within the main loop the following big steps are done (for some of the
* operations a definition is defined already within uvp.h):
*
* - calculate_dt() Determine the maximal time step size.
* - boundaryvalues() Set the boundary values for the next time step.
* - calculate_fg() Determine the values of F and G (diffusion and confection).
* This is the right hand side of the pressure equation and used later on for
* the time step transition.
* - calculate_rs()
* - Iterate the pressure poisson equation until the residual becomes smaller
* than eps or the maximal number of iterations is performed. Within the
* iteration loop the operation sor() is used.
* - calculate_uv() Calculate the velocity at the next time step.
*/
int main(int argn, char** args)
{
double **U, **V, **P, **R, **F, **G;
double t = 0.0;
double t_end, xlength, ylength, tau, omg, alpha, eps, Re, GX, GY, PI, UI, VI, dx, dy, dt, res, dt_value;
int n, imax, jmax, itermax, it, i, outputCount;
double nextOutput;
bool outputSpecified = false;
char* paraviewOutput = "./Paraview/cavity100";
char* inputFile = "./cavity100.dat";
/* statistics */
int sumIter, maxIter, minIter;
double minTimeStep, maxTimestep;
clock_t begin, end;
double time_spent;
sumIter = 0;
maxIter = 0;
maxTimestep = 0;
begin = clock();
/* Parse command line arguments */
if (argn > 2)
{
for (i = 1; i < argn; i++)
{
if (strcmp(args[i], "-i") == 0)
{
inputFile = args[i + 1];
if (!outputSpecified)
paraviewOutput = "./Paraview/sim";
}
if (strcmp(args[i], "-o") == 0)
{
paraviewOutput = args[i + 1];
outputSpecified = true;
}
}
}
else if (argn == 2)
{
/* input file is the single argument besides fctn-name */
inputFile = args[1];
}
/* Initialization */
read_parameters(inputFile, &Re, &UI, &VI, &PI, &GX, &GY, &t_end, &xlength, &ylength, &dt, &dx, &dy, &imax, &jmax, &alpha, &omg, &tau, &itermax, &eps, &dt_value);
U = matrix(0, imax, 0, jmax + 1);
V = matrix(0, imax + 1, 0, jmax);
P = matrix(0, imax + 1, 0, jmax + 1);
R = matrix(0, imax + 1, 0, jmax + 1);
F = matrix(0, imax, 0, jmax);
G = matrix(0, imax, 0, jmax);
n = 0;
nextOutput = dt_value;
init_uvp(UI, VI, PI, imax, jmax, U, V, P);
minIter = itermax;
minTimeStep = t_end;
write_vtkFile(paraviewOutput,0,xlength,ylength,imax,jmax,dx,dy,U,V,P);
outputCount = 1;
while (t < t_end)
{
calculate_dt(Re, tau, &dt, dx, dy, imax, jmax, U, V);
if (dt < minTimeStep)
minTimeStep = dt;
if (dt > maxTimestep)
maxTimestep = dt;
boundaryvalues(imax, jmax, U, V);
calculate_fg(Re, GX, GY, alpha, dt, dy, dy, imax, jmax, U, V, F, G);
calculate_rs(dt, dx, dy, imax, jmax, F, G, R);
it = 0;
while(++it < itermax)
{
sor(omg, dx, dy, imax, jmax, P, R, &res);
if (res <= eps)
break;
}
if (res > eps)
fprintf(stderr, "WARNING: SOR did not converge in timestep %d, residual: %f\n", n + 1, res);
if (it > maxIter)
maxIter = it;
if (it < minIter)
minIter = it;
sumIter += it;
calculate_uv(dt, dx, dy, imax, jmax, U, V, F, G, P);
t = t + dt;
n++;
if (t >= nextOutput)
{
write_vtkFile(paraviewOutput,outputCount,xlength,ylength,imax,jmax,dx,dy,U,V,P);
nextOutput += dt_value;
outputCount++;
}
}
end = clock();
time_spent = (double) (end - begin) / CLOCKS_PER_SEC;
/* print statistics */
printf("Simulation took %f seconds\n", time_spent);
printf("Number of timesteps: %d\n", n);
printf("Min. timestep: %f Max. timestep: %f Avg. timestep: %f\n", minTimeStep, maxTimestep, t_end/n);
printf("Min. # iterations: %d Max. # iterations: %d Avg: %f\n", minIter, maxIter, sumIter/(double) n);
/* Free memory */
free_matrix(U, 0, imax, 0, jmax + 1);
free_matrix(V, 0, imax + 1, 0, jmax);
free_matrix(P, 0, imax + 1, 0, jmax + 1);
free_matrix(R, 0, imax, 0 ,jmax);
free_matrix(F, 0, imax, 0, jmax);
free_matrix(G, 0, imax, 0, jmax);
return 0;
}