Use Joback as ideal gas model for the PR eos (#10)

Use Joback as ideal gas model for the PR eos

src/cubic.rs

@@ -1,5 +1,7 @@
-use crate::equation_of_state::{EquationOfState, HelmholtzEnergy, HelmholtzEnergyDual};
-use crate::joback::JobackRecord;
+use crate::equation_of_state::{
+ EquationOfState, HelmholtzEnergy, HelmholtzEnergyDual, IdealGasContribution,
+};
+use crate::joback::{Joback, JobackRecord};
 use crate::parameter::{Identifier, Parameter, ParameterError, PureRecord};
 use crate::si::{GRAM, MOL};
 use crate::state::StateHD;
@@ -144,11 +146,19 @@ impl Parameter for PengRobinsonParameters {
 
 pub struct PengRobinson {
  parameters: Rc<PengRobinsonParameters>,
+ ideal_gas: Joback,
 }
 
 impl PengRobinson {
  pub fn new(parameters: Rc<PengRobinsonParameters>) -> Self {
- Self { parameters }
+ let ideal_gas = parameters.joback_records.as_ref().map_or_else(
+ || Joback::default(parameters.tc.len()),
+ |j| Joback::new(j.clone()),
+ );
+ Self {
+ parameters,
+ ideal_gas,
+ }
  }
 }
 
@@ -204,6 +214,10 @@ impl EquationOfState for PengRobinson {
  {
  vec![("Peng-Robinson".into(), self.evaluate_residual(state))]
  }
+
+ fn ideal_gas(&self) -> &dyn IdealGasContribution {
+ &self.ideal_gas
+ }
 }
 
 impl MolarWeight<SIUnit> for PengRobinson {