Add a version of UnitSystem.convert that handles default values

include/cantera/base/Units.h

@@ -17,6 +17,7 @@ namespace Cantera
 {
 
 class AnyValue;
+class AnyMap;
 
 //! A representation of the units associated with a dimensional quantity.
 /*!
@@ -131,6 +132,16 @@ public:
     double convert(const AnyValue& val, const std::string& dest) const;
     double convert(const AnyValue& val, const Units& dest) const;
 
+    //! Convert the value at `node[key]` to the units specified in `dest`. If
+    //! the input is a double, convert it using the default units. If the input
+    //! is a string, treat this as a dimensioned value, e.g. '988 kg/m^3' and
+    //! convert from the specified units. If the key is missing, the `default_`
+    //! value is returned.
+    double convert(const AnyMap& node, const std::string key,
+                   const std::string& dest, double default_) const;
+    double convert(const AnyMap& node, const std::string key,
+                   const Units& dest, double default_) const;
+
     //! Convert an array of AnyValue nodes to the units specified in `dest`. For
     //! each node, if the value is a double, convert it using the default units,
     //! and if it is a string, treat it as a value with the given dimensions.
@@ -154,6 +165,14 @@ public:
     //! convert from the specified units.
     double convertMolarEnergy(const AnyValue& val, const std::string& dest) const;
 
+    //! Convert the value at `node[key]` to the molar energy units specified in
+    //! `dest`. If the input is a double, convert it using the default units. If
+    //! the input is a string, treat this as a dimensioned value, e.g. '988
+    //! cal/mol' and convert from the specified units. If the key is missing,
+    //! the `default_` value is returned.
+    double convertMolarEnergy(const AnyMap& node, const std::string& key,
+                              const std::string& dest, double default_) const;
+
 private:
     //! Factor to convert mass from this unit system to kg
     double m_mass_factor;

src/base/Units.cpp

@@ -326,6 +326,27 @@ double UnitSystem::convert(const AnyValue& v, const Units& dest) const
     }
 }
 
+double UnitSystem::convert(const AnyMap& node, const std::string key,
+                           const std::string& dest, double default_) const
+{
+    if (node.hasKey(key)) {
+        return convert(node.at(key), Units(dest));
+    } else {
+        return default_;
+    }
+}
+
+double UnitSystem::convert(const AnyMap& node, const std::string key,
+                           const Units& dest, double default_) const
+{
+    if (node.hasKey(key)) {
+        return convert(node.at(key), dest);
+    } else {
+        return default_;
+    }
+}
+
+
 vector_fp UnitSystem::convert(const std::vector<AnyValue>& vals,
                               const std::string& dest) const
 {
@@ -402,4 +423,15 @@ double UnitSystem::convertMolarEnergy(const AnyValue& v,
     }
 }
 
+double UnitSystem::convertMolarEnergy(
+    const AnyMap& node, const std::string& key,
+    const std::string& dest, double default_) const
+{
+    if (node.hasKey(key)) {
+        return convertMolarEnergy(node.at(key), dest);
+    } else {
+        return default_;
+    }
+}
+
 }

src/thermo/SpeciesThermoFactory.cpp

@@ -145,10 +145,7 @@ static SpeciesThermoInterpType* newNasaThermoFromXML(vector<XML_Node*> nodes)
 void setupSpeciesThermo(SpeciesThermoInterpType& thermo,
                         const AnyMap& node, const UnitSystem& units)
 {
-    double Pref = OneAtm;
-    if (node.hasKey("reference-pressure")) {
-        Pref = units.convert(node.at("reference-pressure"), "Pa");
-    }
+    double Pref = units.convert(node, "reference-pressure", "Pa", OneAtm);
     thermo.setRefPressure(Pref);
 }
 

test/general/test_units.cpp

@@ -82,3 +82,12 @@ TEST(Units, from_anymap) {
     EXPECT_DOUBLE_EQ(U.convert(k1[0], "m^3/kmol"), 1e-9*5e2);
     EXPECT_DOUBLE_EQ(U.convertMolarEnergy(k1[2], "J/kmol"), 29000);
 }
+
+TEST(Units, from_anymap_default) {
+    AnyMap m = AnyMap::fromYamlString("{p0: 10 atm, h0: 10 cal/kmol}");
+    UnitSystem U;
+    EXPECT_DOUBLE_EQ(U.convert(m, "p0", "Pa", 999), 10*OneAtm);
+    EXPECT_DOUBLE_EQ(U.convert(m, "p1", "Pa", 999), 999);
+    EXPECT_DOUBLE_EQ(U.convert(m, "h0", "J/kmol", 999), 41.84);
+    EXPECT_DOUBLE_EQ(U.convert(m, "h1", "J/kmol", 999), 999);
+}