// 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,
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';
}
}
}
// Creating loss
void createloss2d(Loss &lass, double eps, double Cour,
double loss){
double radius = 400;
int sourcex = 450, sourcex2 = 250;
int sourcey = 750, sourcey2 = 100;
double dist, var, Q, epsp, mup, dist2, var_old;
double cutoff = 1.5;
for (size_t dx = 0; dx < spacex; dx++){
for (size_t dy = 0; dy < spacey; dy++){
dist = sqrt((dx - sourcex)*(dx - sourcex)
+ (dy - sourcey)*(dy - sourcey));
dist2 = sqrt((dx - sourcex2)*(dx - sourcex2)
+ (dy - sourcey2)*(dy - sourcey2));
// if (dx > 100 && dx < 150 && dy > 75 && dy < 125){
if (dist < radius){
// if (dist > 100000000){
Q = cbrt(-(radius / dist) + sqrt((radius/dist)
* (radius/dist) + (1.0/27.0)));
var = (Q - (1.0 / (3.0 * Q))) * (Q - (1.0 / (3.0 * Q)));
// var = radius / dist;
// var = 1.1;
if (abs(var - var_old) > cutoff){
var = var_old;
}
if (var > 10){
var = 10;
}
if (isnan(var)){
var = var_old;
}
epsp = eps / (var * var);
mup = 1 / (var * var);
/*
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) = Cour * epsp /(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) = Cour * (mup / eps) / (1.0 + loss);
lass.HxE(dx, dy) = Cour * (mup / eps) / (1.0 + loss);
lass.HxH(dx, dy) = (1.0 - loss) / (1.0 + loss);
/*
// PEC stuff
lass.EzH(dx, dy) = 0;
lass.EzE(dx, dy) = 0;
lass.HyH(dx, dy) = 0;
lass.HyE(dx, dy) = 0;
lass.HxE(dx, dy) = 0;
lass.HxH(dx, dy) = 0;
*/
var_old = var;
}
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) = Cour * eps /(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) = Cour * (1.0 / eps) / (1.0 + loss);
lass.HxE(dx, dy) = Cour * (1.0 / eps) / (1.0 + loss);
lass.HxH(dx, dy) = (1.0 - loss) / (1.0 + loss);
*/
lass.EzH(dx, dy) = Cour * eps;
lass.EzE(dx, dy) = 1.0;
lass.HyH(dx, dy) = 1.0;
lass.HyE(dx, dy) = Cour * (1.0 / eps);
lass.HxE(dx, dy) = Cour * (1.0 / eps);
lass.HxH(dx, dy) = 1.0;
}
}
}
//return lass;
}