// Newton's method to calculate roots
bigfloat AlgRemez::rtnewt(bigfloat *poly, long i, bigfloat x1,
bigfloat x2, bigfloat xacc) {
int j;
bigfloat df, dx, f, rtn;
rtn=(bigfloat)0.5*(x1+x2);
for (j=1; j<=JMAX;j++) {
f = polyEval(rtn, poly, i);
df = polyDiff(rtn, poly, i);
dx = f/df;
rtn -= dx;
//if ((x1-rtn)*(rtn-x2) < (bigfloat)0.0)
//printf("Jumped out of brackets in rtnewt\n");
if (abs_bf(dx) < xacc) return rtn;
}
printf("Maximum number of iterations exceeded in rtnewt\n");
return 0.0;
}
// Newton's method to calculate roots
bigfloat AlgRemez::rtnewt(bigfloat *poly, long i, bigfloat x1, bigfloat x2, bigfloat xacc) {
char *fname = "rtnnewt(bigfloat *, long, bigfloatm bigfloat, bigfloat)";
VRB.Func(cname,fname);
int j;
bigfloat df, dx, f, rtn;
rtn=(bigfloat)0.5*(x1+x2);
for (j=1; j<=JMAX;j++) {
f = polyEval(rtn, poly, i);
df = polyDiff(rtn, poly, i);
dx = f/df;
rtn -= dx;
if ((x1-rtn)*(rtn-x2) < (bigfloat)0.0)
VRB.Warn(cname,fname,"Jumped out of brackets in rtnewt\n");
if (abs_bf(dx) < xacc) return rtn;
}
VRB.Warn(cname,fname,"Maximum number of iterations exceeded in rtnewt\n");
return 0.0;
}
