int main(void){
double *u_past;
double *u_present;
double delta_x=0.01;
int n_x = (int)(10.0/delta_x);
double delta_t = 1E-4;
int n_t = (int)(2.0/delta_t);
double c = 1.0;
int i;
/*reserva memoria*/
u_past = malloc(n_x * sizeof(double));
u_present = malloc(n_x * sizeof(double));
/*inicializacion*/
initial_condition(u_past, n_x, delta_x);
for(i=0;i<n_t;i++){
update_u(u_present, u_past, n_x,delta_x, delta_t, c);
copy(u_present, u_past, n_x);
}
/*imprime en pantalla*/
print_u(u_past, n_x);
return 0;
}
tree
hide_evolution_in_other_loops_than_loop (tree chrec,
unsigned loop_num)
{
struct loop *loop = get_loop (cfun, loop_num), *chloop;
if (automatically_generated_chrec_p (chrec))
return chrec;
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
chloop = get_chrec_loop (chrec);
if (chloop == loop)
return build_polynomial_chrec
(loop_num,
hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num),
CHREC_RIGHT (chrec));
else if (flow_loop_nested_p (chloop, loop))
/* There is no evolution in this loop. */
return initial_condition (chrec);
else
{
gcc_assert (flow_loop_nested_p (loop, chloop));
return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num);
}
default:
return chrec;
}
}
tree
hide_evolution_in_other_loops_than_loop (tree chrec,
unsigned loop_num)
{
if (automatically_generated_chrec_p (chrec))
return chrec;
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
if (CHREC_VARIABLE (chrec) == loop_num)
return build_polynomial_chrec
(loop_num,
hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num),
CHREC_RIGHT (chrec));
else if (CHREC_VARIABLE (chrec) < loop_num)
/* There is no evolution in this loop. */
return initial_condition (chrec);
else
return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num);
default:
return chrec;
}
}
tree
initial_condition (tree chrec)
{
if (automatically_generated_chrec_p (chrec))
return chrec;
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
return initial_condition (CHREC_LEFT (chrec));
else
return chrec;
}
int main()
{
const double ti=0.0;
const double te=17.0652165601579625588917206249;
std::vector<double> position;
std::vector<double> velocity;
initial_condition(position, velocity);
//euler(position, velocity, ti, te);
rk4(position, velocity, ti, te);
return 0;
}
static bool main_loop (void) {
unsigned int app_state = 0;
unsigned long int counter = 0;
double s, t;
initial_condition(n, px, py, vx, vy, m);
s = 0.0;
NBODY_OMP_PARALLEL
do {
NBODY_OMP_MASTER
{
t = timer();
}
physics_advance(dt, n, px, py, vx, vy, m);
NBODY_OMP_MASTER
{
t = timer() - t;
s += t;
if (draw_redraw()) {
draw_particles(dt, n, px, py, vx, vy, m);
app_state = draw_input(app_state, &dt);
}
counter += 1;
if ((counter % 1000LU) == 0)
printf("%lu\n", counter);
}
NBODY_OMP_BARRIER
;
} while (! (app_state & EXIT) &&
! (app_state & RESET));
printf("%lu physics iterations over %f seconds, ratio %f\n",
counter, s, counter/s);
return app_state & RESET;
}
int main(){
double x_f = 1.0;
int n_x = 1000;
double delta_x = 0.001;
double delta_t = 5E-4;
int n_t = 350.0;
double c = 1.0;
double r = c * delta_t/delta_x;
double *u_past = malloc(n_x*sizeof(double));
double *u_present = malloc(n_x*sizeof(double));
double *u_future = malloc(n_x*sizeof(double));
initial_condition(u_past, n_x, delta_x);
/*print_u(u_past, n_x, delta_x);*/
u_past[0] = 0.0;
u_past[n_x-1] = 0.0;
u_present[0] = 0.0;
u_present[n_x-1] = 0.0;
first_iteration(u_present, u_past, n_x, r);
copy(u_present, u_past, n_x);
/*print_u(u_present, n_x, delta_x);*/
int i;
for(i=0;i<n_t;i++){
update_u(u_future, u_present, u_past, n_x, r);
copy(u_present, u_past, n_x);
copy(u_future, u_present, n_x);
}
print_u(u_present, n_x, delta_x);
return 0;
}
int main ( )
/******************************************************************************/
/*
Purpose:
FD1D_ADVECTION_FTCS solves the advection equation using the FTCS method.
Discussion:
The FTCS method is unstable for the advection problem.
Given a smooth initial condition, successive FTCS approximations will
exhibit erroneous oscillations of increasing magnitude.
Licensing:
This code is distributed under the GNU LGPL license.
Modified:
25 December 2012
Author:
John Burkardt
*/
{
double a;
double b;
double c;
char command_filename[] = "advection_commands.txt";
FILE *command_unit;
char data_filename[] = "advection_data.txt";
FILE *data_unit;
double dt;
double dx;
int i;
int j;
int jm1;
int jp1;
int nx;
int nt;
int nt_step;
int plotstep;
double t;
double *u;
double *unew;
double *x;
timestamp ( );
printf ( "\n" );
printf ( "FD1D_ADVECTION_FTCS:\n" );
printf ( " C version\n" );
printf ( "\n" );
printf ( " Solve the constant-velocity advection equation in 1D,\n" );
printf ( " du/dt = - c du/dx\n" );
printf ( " over the interval:\n" );
printf ( " 0.0 <= x <= 1.0\n" );
printf ( " with periodic boundary conditions, and\n" );
printf ( " with a given initial condition\n" );
printf ( " u(0,x) = (10x-4)^2 (6-10x)^2 for 0.4 <= x <= 0.6\n" );
printf ( " = 0 elsewhere.\n" );
printf ( "\n" );
printf ( " We use a method known as FTCS:\n" );
printf ( " FT: Forward Time : du/dt = (u(t+dt,x)-u(t,x))/dt\n" );
printf ( " CS: Centered Space: du/dx = (u(t,x+dx)-u(t,x-dx))/2/dx\n" );
nx = 101;
dx = 1.0 / ( double ) ( nx - 1 );
a = 0.0;
b = 1.0;
x = r8vec_linspace_new ( nx, a, b );
nt = 1000;
dt = 1.0 / ( double ) ( nt );
c = 1.0;
u = initial_condition ( nx, x );
/*
Open data file, and write solutions as they are computed.
*/
data_unit = fopen ( data_filename, "wt" );
t = 0.0;
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[0], t, u[0] );
for ( j = 0; j < nx; j++ )
{
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[j], t, u[j] );
}
fprintf ( data_unit, "\n" );
nt_step = 100;
printf ( "\n" );
printf ( " Number of nodes NX = %d\n", nx );
printf ( " Number of time steps NT = %d\n", nt );
printf ( " Constant velocity C = %g\n", c );
unew = ( double * ) malloc ( nx * sizeof ( double ) );
for ( i = 0; i < nt; i++ )
{
for ( j = 0; j < nx; j++ )
{
jm1 = i4_wrap ( j - 1, 0, nx - 1 );
jp1 = i4_wrap ( j + 1, 0, nx - 1 );
unew[j] = u[j] - c * dt / dx / 2.0 * ( u[jp1] - u[jm1] );
}
for ( j = 0; j < nx; j++ )
{
u[j] = unew[j];
}
if ( i == nt_step - 1 )
{
t = ( double ) ( i ) * dt;
for ( j = 0; j < nx; j++ )
{
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[j], t, u[j] );
}
fprintf ( data_unit, "\n" );
nt_step = nt_step + 100;
}
}
/*
Close the data file once the computation is done.
*/
fclose ( data_unit );
printf ( "\n" );
printf ( " Plot data written to the file \"%s\"\n", data_filename );
/*
Write gnuplot command file.
*/
command_unit = fopen ( command_filename, "wt" );
fprintf ( command_unit, "set term png\n" );
fprintf ( command_unit, "set output 'advection.png'\n" );
fprintf ( command_unit, "set grid\n" );
fprintf ( command_unit, "set style data lines\n" );
fprintf ( command_unit, "unset key\n" );
fprintf ( command_unit, "set xlabel '<---X--->'\n");
fprintf ( command_unit, "set ylabel '<---Time--->'\n" );
fprintf ( command_unit, "splot '%s' using 1:2:3 with lines\n", data_filename );
fprintf ( command_unit, "quit\n" );
fclose ( command_unit );
printf ( " Gnuplot command data written to the file \"%s\"\n",
command_filename );
/*
Free memory.
*/
free ( u );
free ( unew );
free ( x );
/*
Terminate.
*/
printf ( "\n" );
printf ( "FD1D_ADVECTION_FTCS\n" );
printf ( " Normal end of execution.\n" );
printf ( "\n" );
timestamp ( );
return 0;
}
int main ( )
/******************************************************************************/
/*
Purpose:
FD1D_ADVECTION_LAX_WENDROFF: advection equation using Lax-Wendroff method.
Licensing:
This code is distributed under the GNU LGPL license.
Modified:
11 March 2013
Author:
John Burkardt
*/
{
double a;
double b;
double c;
double c1;
double c2;
char command_filename[] = "advection_commands.txt";
FILE *command_unit;
char data_filename[] = "advection_data.txt";
FILE *data_unit;
double dt;
double dx;
int i;
int j;
int jm1;
int jp1;
int nx;
int nt;
int nt_step;
int plotstep;
double t;
double *u;
double *unew;
double *x;
timestamp ( );
printf ( "\n" );
printf ( "FD1D_ADVECTION_LAX_WENDROFF:\n" );
printf ( " C version\n" );
printf ( "\n" );
printf ( " Solve the constant-velocity advection equation in 1D,\n" );
printf ( " du/dt = - c du/dx\n" );
printf ( " over the interval:\n" );
printf ( " 0.0 <= x <= 1.0\n" );
printf ( " with periodic boundary conditions, and\n" );
printf ( " with a given initial condition\n" );
printf ( " u(0,x) = (10x-4)^2 (6-10x)^2 for 0.4 <= x <= 0.6\n" );
printf ( " = 0 elsewhere.\n" );
printf ( "\n" );
printf ( " We modify the FTCS method using the Lax-Wendroff method:\n" );
nx = 101;
dx = 1.0 / ( double ) ( nx - 1 );
a = 0.0;
b = 1.0;
x = r8vec_linspace_new ( nx, a, b );
nt = 1000;
dt = 1.0 / ( double ) ( nt );
c = 1.0;
c1 = 0.5 * c * dt / dx;
c2 = 0.5 * pow ( c * dt / dx, 2 );
u = initial_condition ( nx, x );
/*
Open data file, and write solutions as they are computed.
*/
data_unit = fopen ( data_filename, "wt" );
t = 0.0;
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[0], t, u[0] );
for ( j = 0; j < nx; j++ )
{
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[j], t, u[j] );
}
fprintf ( data_unit, "\n" );
nt_step = 100;
printf ( "\n" );
printf ( " Number of nodes NX = %d\n", nx );
printf ( " Number of time steps NT = %d\n", nt );
printf ( " Constant velocity C = %g\n", c );
printf ( " CFL condition: dt (%g) <= dx / c (%g)\n", dt, dx / c );
unew = ( double * ) malloc ( nx * sizeof ( double ) );
for ( i = 0; i < nt; i++ )
{
for ( j = 0; j < nx; j++ )
{
jm1 = i4_wrap ( j - 1, 0, nx - 1 );
jp1 = i4_wrap ( j + 1, 0, nx - 1 );
unew[j] = u[j] - c1 * ( u[jp1] - u[jm1] )
+ c2 * ( u[jp1] - 2.0 * u[j] + u[jm1] );
}
for ( j = 0; j < nx; j++ )
{
u[j] = unew[j];
}
if ( i == nt_step - 1 )
{
t = ( double ) ( i ) * dt;
for ( j = 0; j < nx; j++ )
{
fprintf ( data_unit, "%10.4f %10.4f %10.4f\n", x[j], t, u[j] );
}
fprintf ( data_unit, "\n" );
nt_step = nt_step + 100;
}
}
/*
Close the data file once the computation is done.
*/
fclose ( data_unit );
printf ( "\n" );
printf ( " Plot data written to the file \"%s\"\n", data_filename );
/*
Write gnuplot command file.
*/
command_unit = fopen ( command_filename, "wt" );
fprintf ( command_unit, "set term png\n" );
fprintf ( command_unit, "set output 'advection_lax_wendroff.png'\n" );
fprintf ( command_unit, "set grid\n" );
fprintf ( command_unit, "set style data lines\n" );
fprintf ( command_unit, "unset key\n" );
fprintf ( command_unit, "set xlabel '<---X--->'\n");
fprintf ( command_unit, "set ylabel '<---Time--->'\n" );
fprintf ( command_unit, "splot '%s' using 1:2:3 with lines\n", data_filename );
fprintf ( command_unit, "quit\n" );
fclose ( command_unit );
printf ( " Gnuplot command data written to the file \"%s\"\n",
command_filename );
/*
Free memory.
*/
free ( u );
free ( unew );
free ( x );
/*
Terminate.
*/
printf ( "\n" );
printf ( "FD1D_ADVECTION_LAX_WENDROFF\n" );
printf ( " Normal end of execution.\n" );
printf ( "\n" );
timestamp ( );
return 0;
}
void update ( int id, int p )
/******************************************************************************/
/*
Purpose:
UPDATE computes the solution of the heat equation.
Discussion:
If there is only one processor ( P == 1 ), then the program writes the
values of X and H to files.
Parameters:
Input, int ID, the id of this processor.
Input, int P, the number of processors.
*/
{
double cfl;
double *h;
FILE *h_file;
double *h_new;
int i;
int j;
int j_min = 0;
int j_max = 400;
double k = 0.002;
int n = 11;
MPI_Status status;
int tag;
double time;
double time_delta;
double time_max = 10.0;
double time_min = 0.0;
double time_new;
double *x;
double x_delta;
FILE *x_file;
double x_max = 1.0;
double x_min = 0.0;
/*
Have process 0 print out some information.
*/
if ( id == 0 )
{
printf ( "\n" );
printf ( " Compute an approximate solution to the time dependent\n" );
printf ( " one dimensional heat equation:\n" );
printf ( "\n" );
printf ( " dH/dt - K * d2H/dx2 = f(x,t)\n" );
printf ( "\n" );
printf ( " for %f = x_min < x < x_max = %f\n", x_min, x_max );
printf ( "\n" );
printf ( " and %f = time_min < t <= t_max = %f\n", time_min, time_max );
printf ( "\n" );
printf ( " Boundary conditions are specified at x_min and x_max.\n" );
printf ( " Initial conditions are specified at time_min.\n" );
printf ( "\n" );
printf ( " The finite difference method is used to discretize the\n" );
printf ( " differential equation.\n" );
printf ( "\n" );
printf ( " This uses %d equally spaced points in X\n", p * n );
printf ( " and %d equally spaced points in time.\n", j_max );
printf ( "\n" );
printf ( " Parallel execution is done using %d processors.\n", p );
printf ( " Domain decomposition is used.\n" );
printf ( " Each processor works on %d nodes, \n", n );
printf ( " and shares some information with its immediate neighbors.\n" );
}
/*
Set the X coordinates of the N nodes.
We don't actually need ghost values of X but we'll throw them in
as X[0] and X[N+1].
*/
x = ( double * ) malloc ( ( n + 2 ) * sizeof ( double ) );
for ( i = 0; i <= n + 1; i++ )
{
x[i] = ( ( double ) ( id * n + i - 1 ) * x_max
+ ( double ) ( p * n - id * n - i ) * x_min )
/ ( double ) ( p * n - 1 );
}
/*
In single processor mode, write out the X coordinates for display.
*/
if ( p == 1 )
{
x_file = fopen ( "x_data.txt", "w" );
for ( i = 1; i <= n; i++ )
{
fprintf ( x_file, " %f", x[i] );
}
fprintf ( x_file, "\n" );
fclose ( x_file );
}
/*
Set the values of H at the initial time.
*/
time = time_min;
h = ( double * ) malloc ( ( n + 2 ) * sizeof ( double ) );
h_new = ( double * ) malloc ( ( n + 2 ) * sizeof ( double ) );
h[0] = 0.0;
for ( i = 1; i <= n; i++ )
{
h[i] = initial_condition ( x[i], time );
}
h[n+1] = 0.0;
time_delta = ( time_max - time_min ) / ( double ) ( j_max - j_min );
x_delta = ( x_max - x_min ) / ( double ) ( p * n - 1 );
/*
Check the CFL condition, have processor 0 print out its value,
and quit if it is too large.
*/
cfl = k * time_delta / x_delta / x_delta;
if ( id == 0 )
{
printf ( "\n" );
printf ( "UPDATE\n" );
printf ( " CFL stability criterion value = %f\n", cfl );
}
if ( 0.5 <= cfl )
{
if ( id == 0 )
{
printf ( "\n" );
printf ( "UPDATE - Warning!\n" );
printf ( " Computation cancelled!\n" );
printf ( " CFL condition failed.\n" );
printf ( " 0.5 <= K * dT / dX / dX = %f\n", cfl );
}
return;
}
/*
In single processor mode, write out the values of H.
*/
if ( p == 1 )
{
h_file = fopen ( "h_data.txt", "w" );
for ( i = 1; i <= n; i++ )
{
fprintf ( h_file, " %f", h[i] );
}
fprintf ( h_file, "\n" );
}
/*
Compute the values of H at the next time, based on current data.
*/
for ( j = 1; j <= j_max; j++ )
{
time_new = ( ( double ) ( j - j_min ) * time_max
+ ( double ) ( j_max - j ) * time_min )
/ ( double ) ( j_max - j_min );
/*
Send H[1] to ID-1.
*/
if ( 0 < id )
{
tag = 1;
MPI_Send ( &h[1], 1, MPI_DOUBLE, id-1, tag, MPI_COMM_WORLD );
}
/*
Receive H[N+1] from ID+1.
*/
if ( id < p-1 )
{
tag = 1;
MPI_Recv ( &h[n+1], 1, MPI_DOUBLE, id+1, tag, MPI_COMM_WORLD, &status );
}
/*
Send H[N] to ID+1.
*/
if ( id < p-1 )
{
tag = 2;
MPI_Send ( &h[n], 1, MPI_DOUBLE, id+1, tag, MPI_COMM_WORLD );
}
/*
Receive H[0] from ID-1.
*/
if ( 0 < id )
{
tag = 2;
MPI_Recv ( &h[0], 1, MPI_DOUBLE, id-1, tag, MPI_COMM_WORLD, &status );
}
/*
Update the temperature based on the four point stencil.
*/
for ( i = 1; i <= n; i++ )
{
h_new[i] = h[i]
+ ( time_delta * k / x_delta / x_delta ) * ( h[i-1] - 2.0 * h[i] + h[i+1] )
+ time_delta * rhs ( x[i], time );
}
/*
H at the extreme left and right boundaries was incorrectly computed
using the differential equation. Replace that calculation by
the boundary conditions.
*/
if ( 0 == id )
{
h_new[1] = boundary_condition ( x[1], time_new );
}
if ( id == p - 1 )
{
h_new[n] = boundary_condition ( x[n], time_new );
}
/*
Update time and temperature.
*/
time = time_new;
for ( i = 1; i <= n; i++ )
{
h[i] = h_new[i];
}
/*
In single processor mode, add current solution data to output file.
*/
if ( p == 1 )
{
for ( i = 1; i <= n; i++ )
{
fprintf ( h_file, " %f", h[i] );
}
fprintf ( h_file, "\n" );
}
}
if ( p == 1 )
{
fclose ( h_file );
}
free ( h );
free ( h_new );
free ( x );
return;
}
int main(int argc, char **argv){
int i,j,k,n;
int nsteps=150;
double dt =0.01;
/* Computational (2D polar) grid coordinates */
int nx1 = 400;
int nx2 = 400;
//number of ghost cells on both sides of each dimension
//only need 1 for piecewise constant method
//need 2 for piecewise linear reconstruction
int num_ghost = 2;
int nx1_r = nx1;
int nx2_r = nx2;
nx1 += 2*num_ghost;
nx2 += 2*num_ghost;
/*non-ghost indices */
int is = num_ghost;
int ie= is+nx1_r;
int js = num_ghost;
int je = js+nx2_r;
//convention: these ranges refer to the non-ghost cells
//however, the ghost cells have real coordinate interpretations
//this means that we must be sure that the number of ghost cells makes sense with the range of coordinates
//this is a big problem if the phi polar coordinate runs the whole range [0,2pi) for example
//further, all mesh structures (zonal and nodal) will be nx1 x nx2, although we may not fill the ghost entries with anything meaningful
//this is to standardize the loop indexing from is:ie
/*another convention: when the phi coordinate is periodic, do we repeat the boundary mesh points? yes for now */
double lx1 = 2.0;//these values are inclusive [x1_i, x1_f]
double lx2 = M_PI;
double x1_i = 0.5;
double x2_i = 0.0;
double dx2 = lx2/(nx2_r-1);
double x2_f = x2_i + lx2;
if(X2_PERIODIC){
dx2 = 2*M_PI/(nx2_r);
lx2 = dx2*(nx2_r-1);
x2_i = 0.0;
}
double dx1 = lx1/(nx1_r-1);
double x1_f = x1_i + lx1;
printf("dx1=%lf dx2=%lf \n",dx1,dx2);
/*Cell centered (zonal) values of computational coordinate position */
double *x1 = (double *) malloc(sizeof(double)*nx1);
double *x2 = (double *) malloc(sizeof(double)*nx2);
x1[is] = x1_i;
x2[js] = x2_i;
for(i=is+1; i<ie; i++){
x1[i] = x1[i-1] + dx1;
// printf("%lf\n",x1[i]);
}
for(i=js+1; i<je; i++){
x2[i] = x2[i-1] + dx2;
//printf("%lf\n",x2[i]);
}
/*Mesh edge (nodal) values of computational coordinate position */
double *x1_b = (double *) malloc(sizeof(double)*(nx1+1));
double *x2_b = (double *) malloc(sizeof(double)*(nx2+1));
x1_b[is] = x1_i - dx1/2;
x2_b[js] = x2_i - dx2/2;
for(i=is+1; i<=ie; i++){
x1_b[i] = x1_b[i-1] + dx1;
// printf("%lf\n",x1_b[i]);
}
for(i=js+1; i<=je; i++){
x2_b[i] = x2_b[i-1] + dx2;
//printf("%lf\n",x2_b[i]);
}
/*Cell centered (zonal) values of physical coordinate position */
//These must be 2D arrays since coordinate transformation is not diagonal
//indexed by x1 rows and x2 columns
double **x = (double **) malloc(sizeof(double *)*nx1);
double **y = (double **) malloc(sizeof(double *)*nx1);
double *dataX = (double *) malloc(sizeof(double)*nx1*nx2);
double *dataY = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
x[i] = &(dataX[nx2*i]);
y[i] = &(dataY[nx2*i]);
}
/*precompute coordinate mappings */
for(i=is; i<ie; i++){
for(j=js; j<je; j++){
x[i][j] = X_physical(x1[i],x2[j]);
y[i][j] = Y_physical(x1[i],x2[j]);
}
}
/*Mesh edge (nodal) values of physical coordinate position */
double **x_b = (double **) malloc(sizeof(double *)*(nx1+1));
double **y_b = (double **) malloc(sizeof(double *)*(nx1+1));
double *dataXb = (double *) malloc(sizeof(double)*(nx1+1)*(nx2+1));
double *dataYb = (double *) malloc(sizeof(double)*(nx1+1)*(nx2+1));
for(i=0; i<=nx1; i++){
x_b[i] = &(dataXb[(nx2+1)*i]);
y_b[i] = &(dataYb[(nx2+1)*i]);
}
for(i=is; i<=ie; i++){
for(j=js; j<=je; j++){
x_b[i][j] = X_physical(x1_b[i],x2_b[j]);
y_b[i][j] = Y_physical(x1_b[i],x2_b[j]);
}
}
/*Edge normal vectors in Cartesian coordinates */
// point radially outward and +\phi
/*Coordinate cell capacity */
double **kappa;
double *datakappa;
kappa = (double **) malloc(sizeof(double *)*nx1);
datakappa = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
kappa[i] = &(datakappa[nx2*i]);
}
for(i=is; i<ie; i++){
for(j=js; j<je; j++){
kappa[i][j] = x1[i]*dx1*dx2/(dx1*dx2); // C_ij/(dx1*dx2)
//capacity in ghost cells
kappa[ie][j] = (x1[ie-1]+dx1)*dx1*dx2/(dx1*dx2);
}
kappa[i][je] = (x1[i]+dx1)*dx1*dx2/(dx1*dx2);
}
/*Average normal edge velocities */
//now we move from cell centered quantities to edge quantities
//the convention in this code is that index i refers to i-1/2 edge
double **U, **V;
double *dataU, *dataV;
U = (double **) malloc(sizeof(double *)*nx1);
V = (double **) malloc(sizeof(double *)*nx1);
dataU = (double *) malloc(sizeof(double)*nx1*nx2);
dataV = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
U[i] = &(dataU[nx2*i]);
V[i] = &(dataV[nx2*i]);
}
/*Option #1 for computing edge velocities: path integral of Cartesian stream function */
/* Stream function */ //probably dont need this array
//this variable is cell centered stream
/* double **stream;
double *datastream;
stream = (double **) malloc(sizeof(double *)*nx1);
datastream = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
stream[i] = &(datastream[nx2*i]);
}
for(i=is; i<ie; i++){
for(j=js; j<je; j++){
stream[i][j] = stream_function(x[i][j],y[i][j]);
}
}
for(i=is; i<ie; i++){
for(j=js; j<je; j++){ //go an additional step to capture nx2_r+1/2
//average the corner stream functions
U[i][j]= (stream_function(X_physical(x1[i]-dx1/2,x2[j]+dx2/2),Y_physical(x1[i]-dx1/2,x2[j]+dx2/2)) -
stream_function(X_physical(x1[i]-dx1/2,x2[j]-dx2/2),Y_physical(x1[i]-dx1/2,x2[j]-dx2/2)))/(dx2);
V[i][j]= -(stream_function(X_physical(x1[i]+dx1/2,x2[j]-dx2/2),Y_physical(x1[i]+dx1/2,x2[j]-dx2/2)) -
stream_function(X_physical(x1[i]-dx1/2,x2[j]-dx2/2),Y_physical(x1[i]-dx1/2,x2[j]-dx2/2)))/dx1;
if(j==10)
printf("i=%d, u,v=%lf,%lf\n",i,U[i][j],V[i][j]);
}
j=je;
U[i][j]= (stream_function(X_physical(x1[i]-dx1/2,x2[j-1]+3*dx2/2),Y_physical(x1[i]-dx1/2,x2[j-1]+3*dx2/2)) -
stream_function(X_physical(x1[i]-dx1/2,x2[j-1]+dx2/2),Y_physical(x1[i]-dx1/2,x2[j-1]+dx2/2)))/(dx2);
V[i][j]= -(stream_function(X_physical(x1[i]+dx1/2,x2[j-1]+dx2/2),Y_physical(x1[i]+dx1/2,x2[j-1]+dx2/2)) -
stream_function(X_physical(x1[i]-dx1/2,x2[j-1]+dx2/2),Y_physical(x1[i]-dx1/2,x2[j-1]+dx2/2)))/dx1;
}
i=ie;
for(j=js; j<je; j++){
U[i][j]= (stream_function(X_physical(x1[i-1]+dx1/2,x2[j]+dx2/2),Y_physical(x1[i-1]+dx1/2,x2[j]+dx2/2)) -
stream_function(X_physical(x1[i-1]+dx1/2,x2[j]-dx2/2),Y_physical(x1[i-1]+dx1/2,x2[j]-dx2/2)))/(dx2);
V[i][j]= -(stream_function(X_physical(x1[i-1]+3*dx1/2,x2[j]-dx2/2),Y_physical(x1[i-1]+3*dx1/2,x2[j]-dx2/2)) -
stream_function(X_physical(x1[i-1]+dx1/2,x2[j]-dx2/2),Y_physical(x1[i-1]+dx1/2,x2[j]-dx2/2)))/dx1;
}
*/
double ux,vy,temp;
for(i=is; i<=ie; i++){
for(j=js; j<=je; j++){
/*Option #2: directly specify velocity in Cartesian coordinate basis as a function of cartesian position*/
//radial face i-1/2
velocity_physical(X_physical(x1_b[i],x2_b[j]+dx2/2),Y_physical(x1_b[i],x2_b[j]+dx2/2),&ux,&vy);
// Average normal edge velocity: just transform face center velocity to local orthonormal basis?
vector_physical_to_coordinate(ux,vy,x2_b[j]+dx2/2,&U[i][j],&temp);
#ifdef HORIZONTAL
//EXACT SOLUTION FOR EDGE VELOCITY FOR HORIZONTAL FLOW
// printf("U_before = %lf\n",U[i][j]);
U[i][j] = (sin(x2_b[j]+dx2) - sin(x2_b[j]))/(dx2);
// printf("U_after = %lf\n",U[i][j]);
#endif
//phi face j-1/2
velocity_physical(X_physical(x1_b[i]+dx1/2,x2_b[j]),Y_physical(x1_b[i]+dx1/2,x2_b[j]),&ux,&vy);
vector_physical_to_coordinate(ux,vy,x2_b[j],&temp,&V[i][j]);
#if defined(SEMI_CLOCK) || defined(GAUSS_CLOCK)
velocity_coordinate(x1_b[i],x2_b[j],&U[i][j],&V[i][j]);
#endif
// printf("U,V = %lf,%lf\n",U[i][j],V[i][j]);
}
}
/* check normalization of velocities */
/* these are naturally not normalized because the cell has finite volume so the edge velocities arent the velocity of the same point */
double norm;
double max_deviation =0.0;
for(i=is; i<=ie; i++){
for(j=js; j<=je; j++){
norm = sqrt(U[i][j]*U[i][j] + V[i][j]*V[i][j]);
if (fabs(norm-1.0) > max_deviation)
max_deviation = fabs(norm-1.0);
// printf("%0.12lf\n",norm);
}
}
// printf("maximum deviation from 1.0 = %0.12lf\n",max_deviation);
/*Option #3: specify velocity in polar coordinates */
/*Check CFL condition, reset timestep */
float **cfl_array;
float *dataCFL;
cfl_array = (float **) malloc(sizeof(float *)*nx1);
dataCFL = (float *) malloc(sizeof(float)*nx1*nx2);
for(i=0; i<nx1; i++){
cfl_array[i] = &(dataCFL[nx2*i]);
}
for(i=1; i<nx1; i++){
for(j=1; j<nx2; j++){ //based on edge velocities or cell centered u,v?
if (i >=is && i< ie && j >=js && j <je)
cfl_array[i][j] = fabs(U[i][j])*dt/dx1 + fabs(V[i][j])*dt/(x1_b[i]*dx2); //use boundary radius
else
cfl_array[i][j] =0.0;
}
}
//find maximum CFL value in domain
float max_cfl = find_max(dataCFL,nx1*nx2);
printf("Largest CFL number = %lf\n",max_cfl);
if (max_cfl > CFL || AUTO_TIMESTEP){//reset timestep if needed
dt = CFL*dt/max_cfl;
for(i=1; i<nx1; i++){
for(j=1; j<nx2; j++){
if (i >=is && i< ie && j >=js && j <je)
cfl_array[i][j] = fabs(U[i][j])*dt/dx1 + fabs(V[i][j])*dt/(x1_b[i]*dx2);
else
cfl_array[i][j] =0.0;
}
}
}
max_cfl = find_max(dataCFL,nx1*nx2);
printf("Largest CFL number = %lf\n",max_cfl);
#ifdef SEMI_CLOCK
nsteps = M_PI/dt;
printf("nsteps = %d, dt = %lf, t_final = %lf\n",nsteps,dt,nsteps*dt);
#endif
#ifdef GAUSS_CLOCK
nsteps = 2*M_PI/dt;
//turn dt down until mod(2*MPI,nsteps) = 0
double remainder = 2*M_PI -nsteps*dt;
double extra = remainder/nsteps;
double dt_new = dt +extra;
printf("nsteps = %d, dt = %lf, dt_new =%lf, remainder = %lf, t_final = %lf t_final_new =%lf\n",nsteps,dt,dt_new,remainder,nsteps*dt,nsteps*dt_new);
max_cfl *= dt_new/dt;
dt = dt_new;
printf("Largest CFL number = %lf\n",max_cfl);
#endif
/*Conserved variable on the computational coordinate mesh*/
double **Q;
double *dataQ;
//make contiguous multiarray
Q = (double **) malloc(sizeof(double *)*nx1);
dataQ = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
Q[i] = &(dataQ[nx2*i]);
}
/*Initial condition */
//specified as a function of cartesian physical cooridnates, as is the stream function
for(i=is; i<ie; i++){
for(j=js; j<je; j++){
Q[i][j] = initial_condition(x[i][j],y[i][j]);
}
}
//net fluctuations/fluxes
double U_plus,U_minus,V_plus,V_minus;
double **net_fluctuation;
double *dataFlux;
net_fluctuation = (double **) malloc(sizeof(double *)*nx1);
dataFlux = (double *) malloc(sizeof(double)*nx1*nx2);
for(i=0; i<nx1; i++){
net_fluctuation[i] = &(dataFlux[nx2*i]);
}
/* Using Visit VTK writer */
char filename[20];
int dims[] = {nx1_r+1, nx2_r+1, 1}; //dont output ghost cells. //nodal variables have extra edge point
int nvars = 2;
int vardims[] = {1, 3}; //Q is a scalar, velocity is a 3-vector
int centering[] = {0, 1}; // Q is cell centered, velocity is defined at edges
const char *varnames[] = {"Q", "edge_velocity"};
/* Curvilinear mesh points stored x0,y0,z0,x1,y1,z1,...*/
//An array of size nI*nJ*nK*3 . These points are nodal, not zonal... unfortunatley
float *pts = (float *) malloc(sizeof(float)*(nx1_r+1)*(nx2_r+1)*3);
//The array should be layed out as (pt(i=0,j=0,k=0), pt(i=1,j=0,k=0), ...
//pt(i=nI-1,j=0,k=0), pt(i=0,j=1,k=0), ...).
int index=0;
for(k=0; k<1; k++){
for(j=js; j<=je; j++){
for(i=is; i<=ie; i++){
pts[index] = x_b[i][j];
pts[++index] = y_b[i][j];
pts[++index] = 0.0;
index++;
}
}
}
/* pack U and V into a vector */
float *edge_vel = (float *) malloc(sizeof(float)*(nx1_r+1)*(nx2_r+1)*3); //An array of size nI*nJ*nK*3
index=0;
for(k=0; k<1; k++){
for(j=js; j<=je; j++){
for(i=is; i<=ie; i++){
vector_coordinate_to_physical(U[i][j],V[i][j], x2[j], &ux,&vy);
//edge_vel[index] = U[i][j];
//edge_vel[++index] = V[i][j];
edge_vel[index] = ux;
edge_vel[++index] = vy;
edge_vel[++index] = 0.0;
index++;
}
}
}
// vars An array of variables. The size of vars should be nvars.
// The size of vars[i] should be npts*vardim[i].
float *realQ;
realQ =(float *) malloc(sizeof(double)*nx1_r*nx2_r);
float *vars[] = {(float *) realQ, (float *)edge_vel};
/*-----------------------*/
/* Main timestepping loop */
/*-----------------------*/
for (n=0; n<nsteps; n++){
/*Boundary conditions */
//bcs are specified along a computational coord direction, but are a function of the physical coordinate of adjacent "real cells"
for(k=0;k<num_ghost; k++){
for (j=js; j<je; j++){
Q[k][j] = bc_x1i(x[is][j],y[is][j]);
Q[nx1-1-k][j] = bc_x1f(x[ie-1][j],y[ie-1][j],(n+1)*dt);
}
for (i=is; i<ie; i++){
if(X2_PERIODIC){
Q[i][k] = Q[i][je-1-k];
Q[i][nx2-1-k] = Q[i][js+k];
}
else{
Q[i][k] = bc_x2i(x[i][js],y[i][js]);
Q[i][nx2-1-k] = bc_x2f(x[i][je-1],y[i][je-1]);
}
}
}
double flux_limiter =0.0;
double *qmu = (double *) malloc(sizeof(double)*3); //manually copy array for computing slope limiters
/* Donor cell upwinding */
for (i=is; i<ie; i++){
for (j=js; j<je; j++){
/* First coordinate */
U_plus = fmax(U[i][j],0.0); // max{U_{i-1/2,j},0.0} LHS boundary
U_minus = fmin(U[i+1][j],0.0); // min{U_{i+1/2,j},0.0} RHS boundary
/*Fluctuations: A^+ \Delta Q_{i-1/2,j} + A^- \Delta Q_{i+1/2,j} */
// net_fluctuation[i][j] = dt/(kappa[i][j]*dx1)*(U_plus*(Q[i][j] - Q[i-1][j]) + U_minus*(Q[i+1][j] - Q[i][j]));
/* First order fluxes: F_i+1/2 - F_i-1/2 */
net_fluctuation[i][j] = dt/(kappa[i][j]*dx1)*(x1_b[i+1]*(fmax(U[i+1][j],0.0)*Q[i][j] + U_minus*Q[i+1][j])-x1_b[i]*(U_plus*Q[i-1][j] + fmin(U[i][j],0.0)*Q[i][j]));
#ifdef SECOND_ORDER
/* Second order fluxes */
if (U[i+1][j] > 0.0){ //middle element is always the upwind element
qmu[0] = Q[i-1][j];
qmu[1] = Q[i][j];
qmu[2] = Q[i+1][j];
flux_limiter= flux_PLM(dx1,qmu);
}
else{
qmu[0] = Q[i+2][j];
qmu[1] = Q[i+1][j];
qmu[2] = Q[i][j];
flux_limiter= flux_PLM(dx1,qmu);
/* if (flux_limiter != 0.0){
printf("i,j: %d,%d F_{i+1/2} flux limiter: %lf\n",i,j,flux_limiter);
printf("Q0 = %lf Q1= %lf Q2 = %lf\n",qmu[0],qmu[1],qmu[2]); } */
}
//F^H_{i+1/2,j}
net_fluctuation[i][j] -= dt/(kappa[i][j]*dx1)*(x1_b[i+1]*(1-dt*fabs(U[i+1][j])/(dx1))*fabs(U[i+1][j])*flux_limiter/2);
// net_fluctuation[i][j] -= dt/(kappa[i][j]*dx1)*((kappa[i][j]/x1_b[i+1]-dt*fabs(U[i+1][j])/(x1_b[i+1]*dx1))*fabs(U[i+1][j])*flux_limiter/2);
// net_fluctuation[i][j] += dt/(kappa[i][j]*dx1)*(x1_b[i+1]*(kappa[i][j]/x1_b[i+1]-dt*fabs(U[i+1][j])/(x1_b[i+1]*dx1))*fabs(U[i+1][j])*flux_limiter/2);
if (U[i][j] > 0.0){
qmu[0] = Q[i-2][j]; //points to the two preceeding bins;
qmu[1] = Q[i-1][j];
qmu[2] = Q[i][j];
flux_limiter= flux_PLM(dx1,qmu);
}
else{
qmu[0] = Q[i+1][j]; //centered around current bin
qmu[1] = Q[i][j];
qmu[2] = Q[i-1][j];
flux_limiter= flux_PLM(dx1,qmu);
}
//F^H_{i-1/2,j}
net_fluctuation[i][j] += dt/(kappa[i][j]*dx1)*(x1_b[i]*(1-dt*fabs(U[i][j])/(dx1))*fabs(U[i][j])*flux_limiter/2);
// net_fluctuation[i][j] += dt/(kappa[i][j]*dx1)*((kappa[i-1][j]/x1_b[i]-dt*fabs(U[i][j])/(x1_b[i]*dx1))*fabs(U[i][j])*flux_limiter/2);
//net_fluctuation[i][j] -= dt/(kappa[i][j]*dx1)*(x1_b[i]*(kappa[i-1][j]/x1_b[i]-dt*fabs(U[i][j])/(x1_b[i]*dx1))*fabs(U[i][j])*flux_limiter/2);
#endif
/* Second coordinate */
V_plus = fmax(V[i][j],0.0); // max{V_{i,j-1/2},0.0} LHS boundary
V_minus = fmin(V[i][j+1],0.0); // min{V_{i,j+1/2},0.0} RHS boundary
/*Fluctuations: B^+ \Delta Q_{i,j-1/2} + B^- \Delta Q_{i,j+1/2} */
//net_fluctuation[i][j] += dt/(kappa[i][j]*dx2)*(V_plus*(Q[i][j] - Q[i][j-1]) + V_minus*(Q[i][j+1] - Q[i][j]));
/* Fluxes: G_i,j+1/2 - G_i,j-1/2 */
net_fluctuation[i][j] += dt/(kappa[i][j]*dx2)*((fmax(V[i][j+1],0.0)*Q[i][j] + V_minus*Q[i][j+1])-(V_plus*Q[i][j-1] + fmin(V[i][j],0.0)*Q[i][j]));
#ifdef SECOND_ORDER
/* Second order fluxes */
if (V[i][j+1] > 0.0){
qmu[0] = Q[i][j-1]; //points to the two preceeding bins;
qmu[1] = Q[i][j];
qmu[2] = Q[i][j+1];
flux_limiter= flux_PLM(dx2,qmu);
}
else{
qmu[0] = Q[i][j+2]; //centered around current bin
qmu[1] = Q[i][j+1];
qmu[2] = Q[i][j];
flux_limiter= flux_PLM(dx2,qmu);
/* if (flux_limiter != 0.0){
printf("i,j: %d,%d F_{i+1/2} flux limiter: %lf\n",i,j,flux_limiter);
printf("Q0 = %lf Q1= %lf Q2 = %lf\n",qmu[0],qmu[1],qmu[2]); } */
}
//G^H_{i,j+1/2}
net_fluctuation[i][j] -= dt/(kappa[i][j]*dx2)*((1-dt*fabs(V[i][j+1])/(kappa[i][j]*dx2))*fabs(V[i][j+1])*flux_limiter/2);
//net_fluctuation[i][j] -= dt/(kappa[i][j]*dx2)*((1-dt*fabs(V[i][j+1])/(dx2))*fabs(V[i][j+1])*flux_limiter/2);
if (V[i][j] > 0.0){
qmu[0] = Q[i][j-2]; //points to the two preceeding bins;
qmu[1] = Q[i][j-1];
qmu[2] = Q[i][j];
flux_limiter = flux_PLM(dx2,qmu);
}
else{
qmu[0] = Q[i][j+1]; //centered around current bin
qmu[1] = Q[i][j];
qmu[2] = Q[i][j-1];
flux_limiter= flux_PLM(dx2,qmu);
}
//G^H_{i,j-1/2}
net_fluctuation[i][j] += dt/(kappa[i][j]*dx2)*((1-dt*fabs(V[i][j])/(kappa[i][j]*dx2))*fabs(V[i][j])*flux_limiter/2);
//net_fluctuation[i][j] += dt/(kappa[i][j]*dx2)*((1-dt*fabs(V[i][j])/(dx2))*fabs(V[i][j])*flux_limiter/2);
#endif
}
}
/*Apply fluctuations */
for (i=is; i<ie; i++)
for (j=js; j<je; j++){
Q[i][j] -= net_fluctuation[i][j];
}
/*Source terms */
for (i=is; i<ie; i++)
for (j=js; j<je; j++){
}
/*Output */
//for now, explicitly copy subarray corresponding to real zonal info:
index=0;
for (k=0; k<1; k++){
for (j=js; j<je; j++){
for (i=is; i<ie; i++){
//index =(j-num_ghost)*nx2_r + (i-num_ghost);
realQ[index] = (float) Q[i][j];//*kappa[i][j]; //\bar{q}=qk density in computational space
index++;
}
}
}
//debug only horizontal flow
/* if (find_max(realQ,nx1_r*nx2_r) > 1.1){
printf("Q greater than 1.0!\n");
for (i=1;i<nx1; i++){
for (j=1; j<nx2; j++){
if (Q[i][j] > 1.0){
printf("i=%d j=%d Q[i][j] = %0.10lf\n",i,j,Q[i][j]);
return(0);
}
}
}
}*/
sprintf(filename,"advect-%.3d.vtk",n);
if(!OUTPUT_INTERVAL){
if (n==nsteps-1) //for only the final result
write_curvilinear_mesh(filename,3,dims, pts, nvars,vardims, centering, varnames, vars);}
else{
if (!(n%OUTPUT_INTERVAL)) //HAVENT CHECKED THIS
write_curvilinear_mesh(filename,3,dims, pts, nvars,vardims, centering, varnames, vars);}
printf("step: %d time: %lf max{Q} = %0.7lf min{Q} = %0.7lf sum{Q} = %0.7lf \n",
n+1,(n+1)*dt,find_max(realQ,nx1_r*nx2_r),find_min(realQ,nx1_r*nx2_r),sum(realQ,nx1_r*nx2_r));
}
return(0);
}