g-bauer · Feb 8, 2024 · Feb 7, 2024
diff --git a/examples/pc_saft_phase_diagram_to_dict.ipynb b/examples/pc_saft_phase_diagram_to_dict.ipynb
diff --git a/feos-core/CHANGELOG.md b/feos-core/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Unreleased
 ### Added
 - Added specific isochoric and isobaric heat capacities to the Python interface. [#223](https://github.com/feos-org/feos/pull/223))
+- Added `to_dict` method for `PyStateVec`. [#224](https://github.com/feos-org/feos/pull/224)
+
+### Fixed
+- Added comparison for pressures of both phases in `PyPhaseDiagram.to_dict` to make the method work with `spinodal` constructor. [#224](https://github.com/feos-org/feos/pull/224)
 
 ## [0.6.1] 2024-01-11
 ### Fixed

diff --git a/feos-core/src/python/phase_equilibria.rs b/feos-core/src/python/phase_equilibria.rs
@@ -906,7 +906,7 @@ macro_rules! impl_phase_equilibrium {
             #[pyo3(signature = (contributions=Contributions::Total), text_signature = "($self, contributions)")]
             pub fn to_dict(&self, contributions: Contributions) -> HashMap<String, Vec<f64>> {
                 let n = self.0.states[0].liquid().eos.components();
-                let mut dict = HashMap::with_capacity(8 + 2 * n);
+                let mut dict = HashMap::with_capacity(16 + 2 * n);
                 if n != 1 {
                     let xs = self.0.liquid().molefracs();
                     let ys = self.0.vapor().molefracs();
@@ -916,7 +916,18 @@ macro_rules! impl_phase_equilibrium {
                     }
                 }
                 dict.insert(String::from("temperature"), self.0.vapor().temperature().convert_into(KELVIN).into_raw_vec());
-                dict.insert(String::from("pressure"), self.0.vapor().pressure().convert_into(PASCAL).into_raw_vec());
+
+                // Check if liquid and vapor pressures are different (e.g. if )
+                let p_v = self.0.vapor().pressure().convert_into(PASCAL).into_raw_vec();
+                let p_l = self.0.liquid().pressure().convert_into(PASCAL).into_raw_vec();
+                let different_pressures = p_v.iter().zip(p_l.iter()).any(|(pv, pl)| (pv - pl).abs() / pv > 1e-3);
+
+                if different_pressures {
+                    dict.insert(String::from("pressure vapor"), p_v);
+                    dict.insert(String::from("pressure liquid"), p_l);
+                }else {
+                    dict.insert(String::from("pressure"), p_v);
+                }
                 dict.insert(String::from("density liquid"), self.0.liquid().density().convert_into(MOL / METER.powi::<P3>()).into_raw_vec());
                 dict.insert(String::from("density vapor"), self.0.vapor().density().convert_into(MOL / METER.powi::<P3>()).into_raw_vec());
                 dict.insert(String::from("mass density liquid"), self.0.liquid().mass_density().convert_into(KILOGRAM / METER.powi::<P3>()).into_raw_vec());

diff --git a/feos-core/src/python/state.rs b/feos-core/src/python/state.rs
@@ -1307,6 +1307,53 @@ macro_rules! impl_state {
             fn get_massfracs<'py>(&self, py: Python<'py>) -> &'py PyArray2<f64> {
                 StateVec::from(self).massfracs().view().to_pyarray(py)
             }
+
+            /// Returns selected properties of a StateVec as dictionary.
+            ///
+            /// Parameters
+            /// ----------
+            /// contributions : Contributions, optional
+            ///     The contributions to consider when calculating properties.
+            ///     Defaults to Contributions.Total.
+            ///
+            /// Returns
+            /// -------
+            /// Dict[str, List[float]]
+            ///     Keys: property names. Values: property for each state.
+            ///
+            /// Notes
+            /// -----
+            /// - temperature : K
+            /// - pressure : Pa
+            /// - densities : mol / m³
+            /// - mass densities : kg / m³
+            /// - molar enthalpies : kJ / mol
+            /// - molar entropies : kJ / mol / K
+            /// - specific enthalpies : kJ / kg
+            /// - specific entropies : kJ / kg / K
+            /// - xi: molefraction of component i
+            /// - component index `i` matches to order of components in parameters.
+            #[pyo3(signature = (contributions=Contributions::Total), text_signature = "($self, contributions)")]
+            pub fn to_dict(&self, contributions: Contributions) -> HashMap<String, Vec<f64>> {
+                let states = StateVec::from(self);
+                let n = states.0[0].eos.components();
+                let mut dict = HashMap::with_capacity(8 + n);
+                if n != 1 {
+                    let xs = states.molefracs();
+                    for i in 0..n {
+                        dict.insert(String::from(format!("x{}", i)), xs.column(i).to_vec());
+                    }
+                }
+                dict.insert(String::from("temperature"), states.temperature().convert_into(KELVIN).into_raw_vec());
+                dict.insert(String::from("pressure"), states.pressure().convert_into(PASCAL).into_raw_vec());
+                dict.insert(String::from("density"), states.density().convert_into(MOL / METER.powi::<P3>()).into_raw_vec());
+                dict.insert(String::from("mass density"), states.mass_density().convert_into(KILOGRAM / METER.powi::<P3>()).into_raw_vec());
+                dict.insert(String::from("molar enthalpy"), states.molar_enthalpy(contributions).convert_into(KILO * JOULE / MOL).into_raw_vec());
+                dict.insert(String::from("molar entropy"), states.molar_entropy(contributions).convert_into(KILO * JOULE / KELVIN / MOL).into_raw_vec());
+                dict.insert(String::from("specific enthalpy"), states.specific_enthalpy(contributions).convert_into(KILO * JOULE / KILOGRAM).into_raw_vec());
+                dict.insert(String::from("specific entropy"), states.specific_entropy(contributions).convert_into(KILO * JOULE / KELVIN / KILOGRAM).into_raw_vec());
+                dict
+            }
         }
     };
 }