EVOLUTION-MANAGER

Edit File: PJ_nell_h.c

#define PJ_LIB__ # include <projects.h> PROJ_HEAD(nell_h, "Nell-Hammer") "\n\tPCyl., Sph."; #define NITER 9 #define EPS 1e-7 FORWARD(s_forward); /* spheroid */ xy.x = 0.5 * lp.lam * (1. + cos(lp.phi)); xy.y = 2.0 * (lp.phi - tan(0.5 *lp.phi)); return (xy); } INVERSE(s_inverse); /* spheroid */ double V, c, p; int i; p = 0.5 * xy.y; for (i = NITER; i ; --i) { c = cos(0.5 * lp.phi); lp.phi -= V = (lp.phi - tan(lp.phi/2) - p)/(1. - 0.5/(c*c)); if (fabs(V) < EPS) break; } if (!i) { lp.phi = p < 0. ? -HALFPI : HALFPI; lp.lam = 2. * xy.x; } else lp.lam = 2. * xy.x / (1. + cos(lp.phi)); return (lp); } FREEUP; if (P) pj_dalloc(P); } ENTRY0(nell_h) P->es = 0.; P->inv = s_inverse; P->fwd = s_forward; ENDENTRY(P)