enable using the multiparameter ideal gas models independently

feos-org · prehner · Oct 17, 2025 · Oct 16, 2025 · Oct 16, 2025 · Oct 16, 2025
commit 04e3b74b7d50ca58dec4222883608392ee5d65d1
diff --git a/py-feos/Cargo.toml b/py-feos/Cargo.toml
@@ -60,4 +60,5 @@ all_models = [
     "pets",
     "saftvrqmie",
     "saftvrmie",
+    "multiparameter"
 ]
diff --git a/py-feos/src/eos/constructors.rs b/py-feos/src/eos/constructors.rs
@@ -71,14 +71,17 @@ impl PyEquationOfState {
     /// Returns
     /// -------
     /// EquationOfState
-    fn python_ideal_gas(&mut self, ideal_gas: Vec<Bound<'_, PyAny>>) -> PyResult<()> {
-        self.add_ideal_gas(
+    fn python_ideal_gas<'py>(
+        slf: Bound<'py, Self>,
+        ideal_gas: Vec<Bound<'py, PyAny>>,
+    ) -> PyResult<Bound<'py, Self>> {
+        slf.borrow_mut().add_ideal_gas(
             ideal_gas
                 .into_iter()
                 .map(|i| Ok(IdealGasModel::Python(Arc::new(PyIdealGas::new(i)?))))
                 .collect::<PyResult<_>>()?,
         );
-        Ok(())
+        Ok(slf)
     }
 
     /// Ideal gas model of Joback and Reid.
@@ -91,14 +94,14 @@ impl PyEquationOfState {
     /// Returns
     /// -------
     /// EquationOfState
-    fn joback(&mut self, joback: PyGcParameters) -> PyResult<()> {
-        self.add_ideal_gas(
+    fn joback(slf: Bound<'_, Self>, joback: PyGcParameters) -> PyResult<Bound<'_, Self>> {
+        slf.borrow_mut().add_ideal_gas(
             Joback::new(joback.try_convert_homosegmented()?)
                 .into_iter()
                 .map(IdealGasModel::Joback)
                 .collect(),
         );
-        Ok(())
+        Ok(slf)
     }
 
     /// Ideal gas model based on DIPPR equations for the ideal
@@ -112,13 +115,13 @@ impl PyEquationOfState {
     /// Returns
     /// -------
     /// EquationOfState
-    fn dippr(&mut self, dippr: PyParameters) -> PyResult<()> {
-        self.add_ideal_gas(
+    fn dippr(slf: Bound<'_, Self>, dippr: PyParameters) -> PyResult<Bound<'_, Self>> {
+        slf.borrow_mut().add_ideal_gas(
             Dippr::new(dippr.try_convert()?)
                 .into_iter()
                 .map(IdealGasModel::Dippr)
                 .collect(),
         );
-        Ok(())
+        Ok(slf)
     }
 }
diff --git a/py-feos/src/eos/multiparameter.rs b/py-feos/src/eos/multiparameter.rs
@@ -19,7 +19,6 @@ impl PyEquationOfState {
     /// Returns
     /// -------
     /// EquationOfState
-    ///     The equation of state that can be used to compute thermodynamic states.
     #[staticmethod]
     pub fn multiparameter(parameters: PyParameters) -> PyResult<Self> {
         let eos = MultiParameter::new(parameters.try_convert()?);
@@ -31,4 +30,28 @@ impl PyEquationOfState {
             .collect();
         Ok(Self(Arc::new(EquationOfState::new(ideal_gas, residual))))
     }
+
+    /// Ideal gas model used in multiparameter Helmholtz energy equations of state.
+    ///
+    /// Parameters
+    /// ----------
+    /// parameters : Parameters
+    ///     The parameters of the multiparameter Helmholtz equation of state.
+    ///
+    /// Returns
+    /// -------
+    /// EquationOfState
+    pub fn multiparameter_ideal_gas(
+        slf: Bound<'_, Self>,
+        parameters: PyParameters,
+    ) -> PyResult<Bound<'_, Self>> {
+        let eos = MultiParameter::new(parameters.try_convert()?);
+        let ideal_gas = eos
+            .ideal_gas
+            .into_iter()
+            .map(IdealGasModel::MultiParameter)
+            .collect();
+        slf.borrow_mut().add_ideal_gas(ideal_gas);
+        Ok(slf)
+    }
 }