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#include <u.h>
#include <libc.h>
#include "map.h"
static int
Xlagrange(struct place *place, double *x, double *y)
{
double z1,z2;
double w1,w2,t1,t2;
struct place p;
copyplace(place,&p);
if(place->nlat.l<0) {
p.nlat.l = -p.nlat.l;
p.nlat.s = -p.nlat.s;
}
Xstereographic(&p,&z1,&z2);
csqrt(-z2/2,z1/2,&w1,&w2);
cdiv(w1-1,w2,w1+1,w2,&t1,&t2);
*y = -t1;
*x = t2;
if(place->nlat.l<0)
*y = -*y;
return(1);
}
proj
lagrange(void)
{
return(Xlagrange);
}
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