the critical point

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "if97"
-version = "1.4.0"
+version = "1.4.1"
 edition = "2021"
 authors = ["Cheng Maohua <cmh@seu.edu.cn>"]
 description = "The high-speed IAPWS-IF97 package with C and Python binding"
@@ -22,7 +22,7 @@ stdcall = []
 python = ["pyo3"]
 
 [dependencies.pyo3]
-version = "0.15.1"
+version = "0.19.2"
 features = ["extension-module"]
 optional = true
 

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = seuif97
-version = 2.0.7
+version = 2.0.8
 author=Cheng Maohua
 author_email=cmh@seu.edu.cn
 keywords = IAPWS-IF97, IF97

src/cdecl_c_if97.rs

@@ -70,6 +70,14 @@ pub unsafe extern "C" fn px(p: f64, x: f64, o_id: i32) -> f64 {
 /// double tx(double t,double x,short o_id) - the propertry of `o_id` (thermodynamic)
 #[no_mangle]
 pub unsafe extern "C" fn tx(t: f64, x: f64, o_id: i32) -> f64 {
+    if (o_id==OT)
+    {
+        return t;
+    } 
+    if (o_id==OX)
+    {
+        return x;
+    } 
     let T: f64 = t + 273.15;
     if T > T_MAX4 || T < T_MIN4 || x > 1.0 || x < 0.0 {
         return INVALID_VALUE as f64;

src/common/constant.rs

@@ -10,6 +10,8 @@ pub const INVALID_H: i32 = -2103;
 pub const INVALID_PT: i32 = -2201;
 pub const INVALID_HS: i32 = -2202;
 
+pub const FLOAT_ERROR:f64 =1.0e-6;
+
 /// constants  
 pub const K: f64 = 273.15;
 pub const RGAS_WATER: f64 = 0.461526; //gas constant in KJ/(kg K)

src/python_if97.rs

@@ -66,8 +66,16 @@ fn px(p: f64, x: f64, o_id: i32) -> f64 {
 
 #[pyfunction]
 fn tx(t: f64, x: f64, o_id: i32) -> f64 {
+    if (o_id==OT)
+    {
+        return t;
+    } 
+    if (o_id==OX)
+    {
+        return x;
+    } 
     let T: f64 = t + 273.15;
-    if T > T_MAX4 || T < T_MIN4 || x > 1.0 || x < 0.0 {
+    if T>T_MAX4 || T < T_MIN4 || x > 1.0 || x < 0.0 {
         return INVALID_VALUE as f64;
     }
     Tx_reg4(T, x, o_id)

src/r4/region4_pTx.rs

@@ -28,7 +28,7 @@ pub fn p2sat_water(p: f64, o_id: i32) -> f64 {
     } else {
         // region3
         let mut v: f64 = 0.0;
-        if p == PC_WATER {
+        if (p -PC_WATER).abs()<FLOAT_ERROR {
             v = 1.0 / 322.0;
         } else {
             v = pT2v_sat_reg3(p, T, 0.0);
@@ -62,7 +62,7 @@ pub fn p2sat_steam(p: f64, o_id: i32) -> f64 {
     } else {
         //reg3d =ss
         let mut v: f64 = 0.0;
-        if p == PC_WATER {
+        if (p -PC_WATER).abs()<FLOAT_ERROR {
             let v: f64 = 1.0 / 322.0;
         } else {
             let v: f64 = pT2v_sat_reg3(p, T, 1.0);
@@ -85,7 +85,7 @@ pub fn T2sat_water(T: f64, o_id: i32) -> f64 {
     }
 
     let mut p: f64 = 0.0;
-    if T == TC_WATER {
+    if (T - TC_WATER).abs() < FLOAT_ERROR  {
         p = PC_WATER;
     } else {
         p = p_saturation(T);
@@ -99,7 +99,7 @@ pub fn T2sat_water(T: f64, o_id: i32) -> f64 {
     } else {
         // region3
         let mut v: f64 = 0.0;
-        if T == TC_WATER {
+        if (T - TC_WATER).abs() < FLOAT_ERROR {
             if o_id == OS {
                 return SC_WATER;
             };
@@ -126,9 +126,8 @@ pub fn T2sat_steam(T: f64, o_id: i32) -> f64 {
     if o_id == OT {
         return T;
     }
-
     let mut p: f64 = 0.0;
-    if T == TC_WATER {
+    if (T - TC_WATER).abs() < FLOAT_ERROR {
         p = PC_WATER;
     } else {
         p = p_saturation(T);
@@ -142,7 +141,7 @@ pub fn T2sat_steam(T: f64, o_id: i32) -> f64 {
     } else {
         //region3
         let mut v: f64 = 0.0;
-        if T == TC_WATER {
+        if (T - TC_WATER).abs() < FLOAT_ERROR {
             if o_id == OS {
                 return SC_WATER;
             }
@@ -201,7 +200,30 @@ pub fn Tx_reg4(T: f64, x: f64, o_id: i32) -> f64 {
     let p: f64 = p_saturation(T);
     if o_id == OP {
         return p;
-    } else {
-        return px_reg4(p, x, o_id);
+    };
+    if x == 0.0 {
+        return T2sat_water(T, o_id);
+    } else if x == 1.0 {
+        return T2sat_steam(T, o_id);
+    }
+    let mut r: f64 = 0.0;
+    match o_id {
+        OH | OS | OV | OU | OF | OG | OE => {
+            // region 4 x(0,1) return  v,h,s only
+            let mut rl: f64 = 0.0;
+            let mut rv: f64 = 0.0;
+            if T > 623.15 {
+                let dl = 1.0 / pT2v_sat_reg3(p, T, 0.0);
+                rl = Td_reg3(T, dl, o_id);
+                let dv = 1.0 / pT2v_sat_reg3(p, T, 1.0);
+                rv = Td_reg3(T, dv, o_id);
+            } else {
+                rl = pT_reg1(p, T, o_id);
+                rv = pT_reg2(p, T, o_id);
+            }
+            r = rl + x * (rv - rl);
+        }
+        _ => return INVALID_OUTID as f64,
     }
+    r
 }

src/r4/region4_sat_pT.rs

@@ -22,8 +22,7 @@ const n: [f64; 10] = [
 /// saturation pressure, MPa
 pub fn p_saturation(T: f64) -> f64 {
     let mut ps: f64 = 0.0;
-    if T < 273.15 || T > 647.096
-    // TC_WATER=647.096
+    if T < 273.15 || T> T_MAX4
     {
         ps = INVALID_VALUE as f64;
     } else {

src/rust_if97.rs

@@ -207,6 +207,14 @@ pub fn px(p: f64, x: f64, o_id: i32) -> f64 {
 /// ```
 ///
 pub fn tx(t: f64, x: f64, o_id: i32) -> f64 {
+    if (o_id==OT)
+    {
+        return t;
+    } 
+    if (o_id==OX)
+    {
+        return x;
+    } 
     let T: f64 = t + 273.15;
     if T > T_MAX4 || T < T_MIN4 || x > 1.0 || x < 0.0 {
         return INVALID_VALUE as f64;

src/stdcall_c_if97.rs

@@ -70,6 +70,12 @@ pub unsafe extern "stdcall" fn px(p: f64, x: f64, o_id: i32) -> f64 {
 /// double tx(double t,double x,short o_id) - the propertry of `o_id` (thermodynamic)
 #[no_mangle]
 pub unsafe extern "stdcall" fn tx(t: f64, x: f64, o_id: i32) -> f64 {
+    if (o_id == OT) {
+        return t;
+    }
+    if (o_id == OX) {
+        return x;
+    }
     let T: f64 = t + 273.15;
     if T > T_MAX4 || T < T_MIN4 || x > 1.0 || x < 0.0 {
         return INVALID_VALUE as f64;