/**
* Computes x + y without losing precision using ln(x) and ln(y).
*
* @param lna Value.
* @param lnc Value.
* @return Result.
*/
public static double LogSum(float lna, float lnc) {
if (lna == Float.NEGATIVE_INFINITY) return lnc;
if (lnc == Float.NEGATIVE_INFINITY) return lna;
if (lna > lnc) return lna + Special.Log1p(Math.exp(lnc - lna));
return lnc + Special.Log1p(Math.exp(lna - lnc));
}
