Improved TempSensorCalcs

double calcDewPointFast(double T, double RH)
{
 double Td = T - ((100 - RH)/5.);  //https://iridl.ldeo.columbia.edu/dochelp/QA/Basic/dewpoint.html
 if (Td < 0) Td = 0;
 return Td;
}

double calcHeatIndex(double T, double RH)
{
  //  The Rothfusz regression is not appropriate when conditions of temperature and humidity warrant a heat index value below about 80 degrees F.
  //  In those cases, a simpler formula is applied to calculate values consistent with Steadman's results:
  //    HI = 0.5 * {T + 61.0 + [(T-68.0)*1.2] + (RH*0.094)}
  // In practice, the simple formula is computed first and the result averaged with the temperature. If this heat index value is 80 degrees F or higher, the full regression equation along with any adjustment as described above is applied.

  double HI = 0.5 * (T + 61.0 + ((T-68.0)*1.2) + (RH*0.094));

  if (HI > 80.0)
  {
    HI = -42.379 + 2.04901523*T + 10.14333127*RH - .22475541*T*RH - .00683783*T*T - .05481717*RH*RH + .00122874*T*T*RH + .00085282*T*RH*RH - .00000199*T*T*RH*RH;

    //  If the RH is less than 13% and the temperature is between 80 and 112 degrees F
    //    ADJUSTMENT = [(13-RH)/4]*SQRT{[17-ABS(T-95.)]/17}

    if (RH < 13 & (T > 80.0 & T < 112.0))
    {
      double ADJUSTMENT = ((13-RH)/4)*sqrt((17-abs(T-95.))/17);
      HI = HI - ADJUSTMENT;
    }

    //  If the RH is greater than 85% and the temperature is between 80 and 87 degrees F
    //    ADJUSTMENT = [(RH-85)/10] * [(87-T)/5]
    if (RH > 85 & (T > 80.0 & T < 87.0))
    {
      double ADJUSTMENT = ((RH-85)/10) * ((87-T)/5);
      HI = HI - ADJUSTMENT;
    }
  }
  return HI;
}