2 * Generally useful stuff.
21 double hypotD(const double p[D3], const double q[D3]);
22 double hypotD2(const double p[D3], const double q[D3]);
23 double hypotD2plus(const double p[D3], const double q[D3], double add);
25 double magnD(const double pq[D3]);
26 void xprod(double r[D3], const double a[D3], const double b[D3]);
31 # define fma_fast(f1,f2,t) ((f1)*(f2)+(t))
33 #define ffsqa(factor,term) fma_fast((factor),(factor),(term))