FDTD really is a surprisingly simple algorithm. Its core is just 3 nested "for" loops, with two multiplications and a bunch of additions. Run it once to get the electric field from the magnetic field of the surrounding grids, and run again to do the opposite. Just this is enough to model all classical electromagnetism in the universe. #electronics
![void Engine::UpdateVoltages(unsigned int startX, unsigned int numX)
{
unsigned int pos[3];
bool shift[3];
pos[0] = startX;
//voltage updates
for (unsigned int posX=0; posX<numX; ++posX)
{
shift[0]=pos[0];
for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
{
shift[1]=pos[1];
for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
{
shift[2]=pos[2];
//do the updates here
//for x
volt[0][pos[0]][pos[1]][pos[2]] *=
Op->vv[0][pos[0]][pos[1]][pos[2]];
volt[0][pos[0]][pos[1]][pos[2]] +=
Op->vi[0][pos[0]][pos[1]][pos[2]] * (
curr[2][pos[0]][pos[1] ][pos[2] ] -
curr[2][pos[0]][pos[1]-shift[1]][pos[2] ] -
curr[1][pos[0]][pos[1] ][pos[2] ] +
curr[1][pos[0]][pos[1] ][pos[2]-shift[2]]
);
//for y
volt[1][pos[0]][pos[1]][pos[2]] *=
Op->vv[1][pos[0]][pos[1]][pos[2]];
volt[1][pos[0]][pos[1]][pos[2]] +=
Op->vi[1][pos[0]][pos[1]][pos[2]] * (
curr[0][pos[0] ][pos[1]][pos[2] ] -
curr[0][pos[0] ][pos[1]][pos[2]-shift[2]] -
curr[2][pos[0] ][pos[1]][pos[2] ] +
curr[2][pos[0]-shift[0]][pos[1]][pos[2] ]
);
//for z
volt[2][pos[0]][pos[1]][pos[2]] *=
Op->vv[2][pos[0]][pos[1]][pos[2]];
volt[2][pos[0]][pos[1]][pos[2]] +=
Op->vi[2][pos[0]][pos[1]][pos[2]] * (
curr[1][pos[0] ][pos[1] ][pos[2]] -
curr[1][pos[0]-shift[0]][pos[1] ][pos[2]] -
curr[0][pos[0] ][pos[1] ][pos[2]] +
curr[0][pos[0] ][pos[1]-shift[1]][pos[2]]
);
}
}
++pos[0];
}
}](https://keybored.me/photo/preview/640/957637 "void Engine::UpdateVoltages(unsigned int startX, unsigned int numX)
{
unsigned int pos[3];
bool shift[3];
pos[0] = startX;
//voltage updates
for (unsigned int posX=0; posX<numX; ++posX)
{
shift[0]=pos[0];
for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
{
shift[1]=pos[1];
for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
{
shift[2]=pos[2];
//do the updates here
//for x
volt[0][pos[0]][pos[1]][pos[2]] *=
Op->vv[0][pos[0]][pos[1]][pos[2]];
volt[0][pos[0]][pos[1]][pos[2]] +=
Op->vi[0][pos[0]][pos[1]][pos[2]] * (
curr[2][pos[0]][pos[1] ][pos[2] ] -
curr[2][pos[0]][pos[1]-shift[1]][pos[2] ] -
curr[1][pos[0]][pos[1] ][pos[2] ] +
curr[1][pos[0]][pos[1] ][pos[2]-shift[2]]
);
//for y
volt[1][pos[0]][pos[1]][pos[2]] *=
Op->vv[1][pos[0]][pos[1]][pos[2]];
volt[1][pos[0]][pos[1]][pos[2]] +=
Op->vi[1][pos[0]][pos[1]][pos[2]] * (
curr[0][pos[0] ][pos[1]][pos[2] ] -
curr[0][pos[0] ][pos[1]][pos[2]-shift[2]] -
curr[2][pos[0] ][pos[1]][pos[2] ] +
curr[2][pos[0]-shift[0]][pos[1]][pos[2] ]
);
//for z
volt[2][pos[0]][pos[1]][pos[2]] *=
Op->vv[2][pos[0]][pos[1]][pos[2]];
volt[2][pos[0]][pos[1]][pos[2]] +=
Op->vi[2][pos[0]][pos[1]][pos[2]] * (
curr[1][pos[0] ][pos[1] ][pos[2]] -
curr[1][pos[0]-shift[0]][pos[1] ][pos[2]] -
curr[0][pos[0] ][pos[1] ][pos[2]] +
curr[0][pos[0] ][pos[1]-shift[1]][pos[2]]
);
}
}
++pos[0];
}
}")