#include "fdtd-macro-tez.h" #include "fdtd-alloc1.h" #include void gridInit(Grid *g) { double imp0 = 377.0; int mm, nn; /* terms for the PEC scatterer */ double rad, r2, xLocation, yLocation, xCenter, yCenter; Type = teZGrid; SizeX = 92; // size of domain SizeY = 82; MaxTime = 300; // duration of simulation Cdtds = 1.0 / sqrt(2.0); // Courant number ALLOC_2D(g->hz, SizeX - 1, SizeY - 1, double); ALLOC_2D(g->chzh, SizeX - 1, SizeY - 1, double); ALLOC_2D(g->chze, SizeX - 1, SizeY - 1, double); ALLOC_2D(g->ex, SizeX - 1, SizeY, double); ALLOC_2D(g->cexh, SizeX - 1, SizeY, double); ALLOC_2D(g->cexe, SizeX - 1, SizeY, double); ALLOC_2D(g->ey, SizeX, SizeY - 1, double); ALLOC_2D(g->ceye, SizeX, SizeY - 1, double); ALLOC_2D(g->ceyh, SizeX, SizeY - 1, double); /* set electric-field update coefficients */ for (mm = 0; mm < SizeX - 1; mm++) for (nn = 0; nn < SizeY; nn++) { Cexe(mm, nn) = 1.0; Cexh(mm, nn) = Cdtds * imp0; } for (mm = 0; mm < SizeX; mm++) for (nn = 0; nn < SizeY - 1; nn++) { Ceye(mm, nn) = 1.0; Ceyh(mm, nn) = Cdtds * imp0; } /* Set to zero nodes associated with PEC scatterer. * Circular scatterer assumed centered on Hz node * at (xCenter, yCenter). If an Hz node is less than * the radius away from this node, set to zero the * four electric fields that surround that node. */ rad = 12; // radius of circle xCenter = SizeX / 2; yCenter = SizeY / 2; r2 = rad * rad; // square of radius for (mm = 1; mm < SizeX - 1; mm++) { xLocation = mm - xCenter; for (nn = 1; nn < SizeY - 1; nn++) { yLocation = nn - yCenter; if (xLocation * xLocation + yLocation * yLocation < r2) { Cexe(mm, nn) = 0.0; Cexh(mm, nn) = 0.0; Cexe(mm, nn + 1) = 0.0; Cexh(mm, nn + 1) = 0.0; Ceye(mm + 1, nn) = 0.0; Ceyh(mm + 1, nn) = 0.0; Ceye(mm, nn) = 0.0; Ceyh(mm, nn) = 0.0; } } } /* set magnetic-field update coefficients */ for (mm = 0; mm < SizeX - 1; mm++) for (nn = 0; nn < SizeY - 1; nn++) { Chzh(mm, nn) = 1.0; Chze(mm, nn) = Cdtds / imp0; } return; }