1 files changed, 87 insertions, 0 deletions
diff --git a/archive/setup_ellipsoid_initial_guess.cc b/archive/setup_ellipsoid_initial_guess.cc
new file mode 100644
index 0000000..f8ba391
--- /dev/null
+++ b/archive/setup_ellipsoid_initial_guess.cc
@@ -0,0 +1,87 @@
+//
+// This function sets up an ellipsoid in the gridfn h, using the
+// formulas in "ellipsoid.maple" and the Maple-generated C code in
+// "ellipsoid.c":
+//
+// ellipsoid has center (A,B,C), radius (a,b,c)
+// angular coordinate system has center (U,V,W)
+//
+// direction cosines wrt angular coordinate center are (xcos,ycos,zcos)
+// i.e. a point has coordinates (U+xcos*r, V+ycos*r, W+zcos*r)
+//
+// then the equation of the ellipsoid is
+//	(U+xcos*r - A)^2     (V+ycos*r - B)^2     (W+zcos*r - C)^2
+//	-----------------  +  ----------------  +  -----------------  =  1
+//	        a^2                  b^2                   c^2
+//
+// to solve this, we introduce intermediate variables
+//	AU = A - U
+//	BV = B - V
+//	CW = C - W
+//
+namespace {
+void setup_ellipsoid_initial_guess
+	(patch_system& ps,
+	 fp global_center_x, fp global_center_y, fp global_center_z,
+	 fp radius_x, fp radius_y, fp radius_z)
+{
+CCTK_VInfo(CCTK_THORNSTRING,
+	   "   h = ellipsoid: global_center=(%g,%g,%g)",
+	   global_center_x, global_center_y, global_center_z);
+CCTK_VInfo(CCTK_THORNSTRING,
+	   "                  radius=(%g,%g,%g)",
+	   radius_x, radius_y, radius_z);
+
+	for (int pn = 0 ; pn < ps.N_patches() ; ++pn)
+	{
+	patch& p = ps.ith_patch(pn);
+
+		for (int irho = p.min_irho() ; irho <= p.max_irho() ; ++irho)
+		{
+		for (int isigma = p.min_isigma() ;
+		     isigma <= p.max_isigma() ;
+		     ++isigma)
+		{
+		const fp rho = p.rho_of_irho(irho);
+		const fp sigma = p.sigma_of_isigma(isigma);
+		fp xcos, ycos, zcos;
+		p.xyzcos_of_rho_sigma(rho,sigma, xcos,ycos,zcos);
+
+		// set up variables used by Maple-generated code
+		const fp AU = global_center_x - ps.origin_x();
+		const fp BV = global_center_y - ps.origin_y();
+		const fp CW = global_center_z - ps.origin_z();
+		const fp a = radius_x;
+		const fp b = radius_y;
+		const fp c = radius_z;
+
+		// compute the solutions r_plus and r_minus
+		fp r_plus, r_minus;
+		#include "ellipsoid.c"
+
+		// exactly one of the solutions (call it r) should be positive
+		fp r;
+		if      ((r_plus > 0.0) && (r_minus < 0.0))
+		   then r = r_plus;
+		else if ((r_plus < 0.0) && (r_minus > 0.0))
+		   then r = r_minus;
+		else    CCTK_VWarn(-1, __LINE__, __FILE__, CCTK_THORNSTRING,
+				   "\n"
+"   expected exactly one r>0 solution, got 0 or 2!\n"
+"   %s patch (irho,isigma)=(%d,%d) ==> (rho,sigma)=(%g,%g)\n"
+"   direction cosines (xcos,ycos,zcos)=(%g,%g,%g)\n"
+"   ==> r_plus=%g r_minus=%g\n"
+				   ,
+				   p.name(), irho, isigma,
+				   double(rho), double(sigma),
+				   double(xcos), double(ycos), double(zcos),
+				   double(r_plus), double(r_minus));
+		   						/*NOTREACHED*/
+
+		// r = horizon radius at this grid point
+		p.ghosted_gridfn(ghosted_gfns::gfn__h, irho,isigma) = r;
+		}
+		}
+	}
+}
+	  }