pub fn th(t: f64, h: f64, o_id: i32) -> f64
The extended input pair th(t,h,o_id)
use if97::*; let t:f64=300.0-273.15; let h:f64=0.115331273e+3; let p=th(t,h,OP); println!("t={p:.6} h={h:.6} p={p:.6}");