// TFSF boundaries
void TFSF(Field &EM, Loss &lass, Loss1d &lass1d, double Cour, double ppw){
int dx, dy, loc = 0;
// TFSF boundary
Bound first, last;
first.x = 10; last.x = 1990;
first.y = 10; last.y = 1490;
// Update along right edge!
dx = last.x;
for (int dy = first.y; dy <= last.y; dy++){
EM.Hy(dx,dy) += lass.HyE(dx, dy) * EM.Ez1d[dx];
}
// Updating along left edge
dx = first.x - 1;
for (int dy = first.y; dy <= last.y; dy++){
EM.Hy(dx,dy) -= lass.HyE(dx, dy) * EM.Ez1d[dx+1];
}
// Updating along top
dy = last.y;
for (int dx = first.x; dx <= last.x; dx++){
EM.Hx(dx,dy) -= lass.HxE(dx, dy) * EM.Ez1d[dx];
}
// Update along bot
dy = first.y - 1;
for (int dx = first.x; dx <= last.x; dx++){
EM.Hx(dx,dy) += lass.HxE(dx, dy) * EM.Ez1d[dx];
}
// Insert 1d grid stuff here. Update magnetic and electric field
Hupdate1d(EM, lass1d, EM.t);
Eupdate1d(EM, lass1d, EM.t);
//EM.Ez1d[10] = ricker(EM.t,0, Cour);
EM.Ez1d[10] = planewave(EM.t, loc, Cour, ppw);
EM.t++;
std::cout << EM.t << '\n';
// Check mag instead of ricker.
// Update along right
dx = last.x;
for (int dy = first.y; dy <= last.y; dy++){
EM.Ez(dx, dy) += lass.EzH(dx, dy) * EM.Hy1d[dx];
}
// Updating Ez along left
dx = first.x;
for (int dy = first.y; dy <= last.y; dy++){
EM.Ez(dx, dy) -= lass.EzH(dx, dy) * EM.Hy1d[dx - 1];
}
//return EM;
}
void Eupdate2d(Field &EM, Loss &lass, int t){
// update electric field
#pragma omp parallel for
for (size_t dx = 1; dx < spacex - 1; dx++){
for (size_t dy = 1; dy < spacey - 1; dy++){
EM.Ez(dx,dy) = lass.EzE(dx,dy) * EM.Ez(dx,dy)
+ lass.EzH(dx,dy) * ((EM.Hy(dx, dy)
- EM.Hy(dx - 1, dy))
- (EM.Hx(dx,dy)
- EM.Hx(dx, dy - 1)));
}
}
//return EM;
}
// 2 dimensional functions for E / H movement
void Hupdate2d(Field &EM, Loss &lass, int t){
// update magnetic field, x direction
#pragma omp parallel for
for (size_t dx = 0; dx < spacex; dx++){
for (size_t dy = 0; dy < spacey - 1; dy++){
EM.Hx(dx,dy) = lass.HxH(dx,dy) * EM.Hx(dx, dy)
- lass.HxE(dx,dy) * (EM.Ez(dx,dy + 1)
- EM.Ez(dx,dy));
}
}
// update magnetic field, y direction
#pragma omp parallel for
for (size_t dx = 0; dx < spacex - 1; dx++){
for (size_t dy = 0; dy < spacey; dy++){
EM.Hy(dx,dy) = lass.HyH(dx,dy) * EM.Hy(dx,dy)
+ lass.HyE(dx,dy) * (EM.Ez(dx + 1,dy)
- EM.Ez(dx,dy));
}
}
//return EM;
}
// This is the function we writs the bulk of the code in
void FDTD(Field &EM,
int final_time, double eps,
std::ofstream& output){
double loss = 0.00;
double Cour = 1 / sqrt(2), ppw;
int numtry = 10;
Loss lass;
createloss2d(lass, eps, Cour, loss);
Loss1d lass1d;
createloss1d(lass1d, eps, Cour, loss);
// Time looping
for (int q = 0; q < numtry; q++){
ppw = 5 + (1/(double)numtry) * q;
for (int t = 0; t < final_time; t++){
Hupdate2d(EM, lass, t);
TFSF(EM, lass, lass1d, Cour, ppw);
Eupdate2d(EM,lass,t);
ABCcheck(EM, lass);
// Outputting to a file
int check = 30000;
if (t % check == 0 && t != 0){
for (size_t dx = 0; dx < spacex; dx++){
for (size_t dy = 0; dy < spacey; dy++){
output << t << '\t' << dx <<'\t' << dy << '\t'
<< EM.Ez(dx, dy) << '\n';
// '\t' << EM.Hy(dx, dy)
// << '\t' << EM.Hx(dx, dy) << '\t' << '\n';
}
}
output << '\n' << '\n';
}
}
}
}
// This is the function we writs the bulk of the code in
void FDTD(Field EM,
const int final_time, const double eps, const int space, Loss lass,
std::ofstream& output){
// For magnetic field:
// double offset = 0.00005;
// for electric field:
double offset = 0.05;
double loss = 0.0;
double Cour = 1.0 / sqrt(2.0);
// Relative permittivity
for (int dx = 0; dx < space; dx++){
for (int dy = 0; dy < space; dy++){
if (dx > 100 && dx < 150){
lass.EzH(dx, dy) = Cour * eps;
lass.EzE(dx, dy) = 1.0;
lass.HyH(dx, dy) = 1.0;
lass.HyE(dx, dy) = Cour / eps;
lass.HxE(dx, dy) = Cour / eps;
lass.HxH(dx, dy) = 1.0;
/*
lass.EzH(dx, dy) = eps / 9.0 /(1.0 - loss);
lass.EzE(dx, dy) = (1.0 - loss) / (1.0 + loss);
lass.HyH(dx, dy) = (1.0 - loss) / (1.0 + loss);
lass.HyE(dx, dy) = (1.0 / eps) / (1.0 + loss);
lass.HxE(dx, dy) = (1.0 / eps) / (1.0 + loss);
lass.HxH(dx, dy) = (1.0 - loss) / (1.0 + loss);
*/
}
else{
lass.EzH(dx, dy) = Cour * eps;
lass.EzE(dx, dy) = 1.0;
lass.HyH(dx, dy) = 1.0;
lass.HyE(dx, dy) = Cour / eps;
lass.HxE(dx, dy) = Cour / eps;
lass.HxH(dx, dy) = 1.0;
/*
lass.EzH(dx, dy) = eps;
lass.EzE(dx, dy) = 1.0;
lass.HyH(dx, dy) = 1.0;
lass.HyE(dx, dy) = (1.0 / eps);
lass.HxE(dx, dy) = (1.0 / eps);
lass.HxH(dx, dy) = 1.0;
*/
}
}
}
// Time looping
for (int t = 0; t < final_time; t++){
// Linking the final two elements for an ABC
for (int da = 0; da < space; da++){
EM.Hy(da,space - 1) = EM.Hy(da,space - 2);
EM.Hx(space - 1,da) = EM.Hx(space - 2,da);
}
// update magnetic field, y direction
for (int dx = 0; dx < space - 1; dx++){
for (int dy = 0; dy < space; dy++){
EM.Hy(dx,dy) = lass.HyH(dx,dy) * EM.Hy(dx,dy)
+ lass.HyE(dx,dy) * (EM.Ez(dx + 1,dy)
- EM.Ez(dx,dy));
}
}
// update magnetic field, x direction
for (int dx = 0; dx < space; dx++){
for (int dy = 0; dy < space - 1; dy++){
EM.Hx(dx,dy) = lass.HxH(dx,dy) * EM.Hx(dx, dy)
+ lass.HxE(dx,dy) * (EM.Ez(dx,dy + 1)
- EM.Ez(dx,dy));
}
}
// Correction to the H field for the TFSF boundary
// Hy[49] -= exp(-(t - 40.) * (t - 40.)/100.0) / eps;
// Hy[49] -= sin((t-10.0)*0.2)*0.0005;
// Linking the first two elements in the electric field
for (int dy = 0; dy < space; dy++){
EM.Ez(0,dy) = EM.Ez(1,dy);
EM.Ez(space - 1,dy) = EM.Ez(space - 2,dy);
}
// update electric field
for (int dx = 1; dx < space - 1; dx++){
for (int dy = 1; dy < space - 1; dy++){
EM.Ez(dx,dy) = lass.EzE(dx,dy) * EM.Ez(dx,dy)
+ lass.EzH[dx] * (EM.Hy(dx, dy)
- EM.Hy(dx - 1, dy)
- EM.Hx(dx,dy)
- EM.Hx(dx, dy - 1));
}
}
// set src for next step
for (int dy = 0; dy < space; dy++){
EM.Ez(50,dy) += exp(-((t + 1 - 40.) * (t + 1 - 40.))/100.0);
}
// EM.Ez[0] = 0;
// Ez[50] += sin((t - 10.0 + 1)*0.2)*0.0005;
/*
if (t > 0){
Ez[50] = sin(0.1 * t) / (0.1 * t);
}
else{
Ez[50] = 1;
}
*/
if (t % 50 == 0){
for (int dx = 0; dx < space; dx = dx + 50){
for (int dy = 0; dy < space; dy = dy + 50){
output << t << '\t' << dx <<'\t' << dy << '\t'
<< EM.Ez(dx, dy) << '\n';
//output << Ez(dx,dy) + (t * offset) << '\n';
//output << Hy[dx] + (t * offset) << '\n';
}
}
output << '\n' << '\n';
}
}
}
// Checking Absorbing Boundary Conditions (ABC)
void ABCcheck(Field &EM, Loss &lass){
// defining constant for ABC
double c1, c2, c3, temp1, temp2;
temp1 = sqrt(lass.EzH(0,0) * lass.HyE(0,0));
temp2 = 1.0 / temp1 + 2.0 + temp1;
c1 = -(1.0 / temp1 - 2.0 + temp1) / temp2;
c2 = -2.0 * (temp1 - 1.0 / temp1) / temp2;
c3 = 4.0 * (temp1 + 1.0 / temp1) / temp2;
size_t dx, dy;
// Setting ABC for top
for (dx = 0; dx < spacex; dx++){
EM.Ez(dx, spacey - 1) = c1 * (EM.Ez(dx, spacey - 3) + EM.Etop(0, 1, dx))
+ c2 * (EM.Etop(0, 0, dx) + EM.Etop(2, 0 , dx)
-EM.Ez(dx,spacey - 2) -EM.Etop(1, 1, dx))
+ c3 * EM.Etop(1, 0, dx) - EM.Etop(2, 1, dx);
// memorizing fields...
for (dy = 0; dy < 3; dy++){
EM.Etop(dy, 1, dx) = EM.Etop(dy, 0, dx);
EM.Etop(dy, 0, dx) = EM.Ez(dx, spacey - 1 - dy);
}
}
// Setting ABC for bottom
for (dx = 0; dx < spacex; dx++){
EM.Ez(dx,0) = c1 * (EM.Ez(dx, 2) + EM.Ebot(0, 1, dx))
+ c2 * (EM.Ebot(0, 0, dx) + EM.Ebot(2, 0 , dx)
-EM.Ez(dx,1) -EM.Ebot(1, 1, dx))
+ c3 * EM.Ebot(1, 0, dx) - EM.Ebot(2, 1, dx);
// memorizing fields...
for (dy = 0; dy < 3; dy++){
EM.Ebot(dy, 1, dx) = EM.Ebot(dy, 0, dx);
EM.Ebot(dy, 0, dx) = EM.Ez(dx, dy);
}
}
// ABC on right
for (dy = 0; dy < spacey; dy++){
EM.Ez(spacex - 1,dy) = c1 * (EM.Ez(spacex - 3,dy) + EM.Eright(0, 1, dy))
+ c2 * (EM.Eright(0, 0, dy) + EM.Eright(2, 0 , dy)
-EM.Ez(spacex - 2,dy) -EM.Eright(1, 1, dy))
+ c3 * EM.Eright(1, 0, dy) - EM.Eright(2, 1, dy);
// memorizing fields...
for (dx = 0; dx < 3; dx++){
EM.Eright(dx, 1, dy) = EM.Eright(dx, 0, dy);
EM.Eright(dx, 0, dy) = EM.Ez(spacex - 1 - dx, dy);
}
}
// Setting ABC for left side of grid. Woo!
for (dy = 0; dy < spacey; dy++){
EM.Ez(0,dy) = c1 * (EM.Ez(2,dy) + EM.Eleft(0, 1, dy))
+ c2 * (EM.Eleft(0, 0, dy) + EM.Eleft(2, 0 , dy)
-EM.Ez(1,dy) -EM.Eleft(1, 1, dy))
+ c3 * EM.Eleft(1, 0, dy) - EM.Eleft(2, 1, dy);
// memorizing fields...
for (dx = 0; dx < 3; dx++){
EM.Eleft(dx, 1, dy) = EM.Eleft(dx, 0, dy);
EM.Eleft(dx, 0, dy) = EM.Ez(dx, dy);
}
}
// return EM;
}
