[Kinetics] Ensure correct units for pre-exponential factor

Cantera · Jul 22, 2021 · f4595d2 · f4595d2
1 parent a890c5e
commit f4595d2
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Showing 4 changed files with 28 additions and 1 deletion.
diff --git a/include/cantera/kinetics/ReactionRateFactory.h b/include/cantera/kinetics/ReactionRateFactory.h
@@ -76,7 +76,13 @@ shared_ptr<ReactionRateBase> newReactionRate(const std::string& type);
  * @param rate_units Unit system of the reaction rate
  */
 shared_ptr<ReactionRateBase> newReactionRate(
-    const AnyMap& rate_node, const Units& rate_units=Units(1.0));
+    const AnyMap& rate_node, const Units& rate_units);
+
+//! Create a new Rate object using the specified parameters
+/*!
+ * @param rate_node AnyMap node describing reaction rate.
+ */
+shared_ptr<ReactionRateBase> newReactionRate(const AnyMap& rate_node);
 
 //! Retrieve the canoncial rate object name
 /*!

diff --git a/interfaces/cython/cantera/reaction.pyx b/interfaces/cython/cantera/reaction.pyx
@@ -95,6 +95,9 @@ cdef class ReactionRate:
             rate = ReactionRate.from_yaml(
                 "rate-constant: {A: 38.7, b: 2.7, Ea: 6260.0 cal/mol}")
 
+        Units for ``A`` require a unit system with length in ``m`` and quantity in
+        ``kmol`` (standard Cantera units).
+
         :param text:
             The YAML reaction rate string.
         """

diff --git a/interfaces/cython/cantera/test/test_reaction.py b/interfaces/cython/cantera/test/test_reaction.py
@@ -1,5 +1,6 @@
 from math import exp
 from pathlib import Path
+import textwrap
 
 import cantera as ct
 import numpy as np
@@ -188,6 +189,12 @@ def test_from_yaml(self):
         self.assertNear(rate(self.gas.T, self.gas.P),
                         self.rate(self.gas.T, self.gas.P))
 
+    def test_with_units(self):
+        units = "units: {length: cm, quantity: mol}"
+        yaml = f"{textwrap.dedent(self._yaml)}\n{units}"
+        with self.assertRaisesRegex(Exception, "not supported"):
+            rate = ct.ReactionRate.from_yaml(yaml)
+
 
 class TestArrheniusRate(ReactionRateTests, utilities.CanteraTest):
     # test Arrhenius rate expressions

diff --git a/src/kinetics/ReactionRateFactory.cpp b/src/kinetics/ReactionRateFactory.cpp
@@ -72,6 +72,17 @@ shared_ptr<ReactionRateBase> newReactionRate(
         ReactionRateFactory::factory()->create(type, rate_node, rate_units));
 }
 
+shared_ptr<ReactionRateBase> newReactionRate(const AnyMap& rate_node)
+{
+    UnitSystem system = rate_node.units();
+    if (system.convertTo(1., "m") != 1. || system.convertTo(1., "kmol") != 1.) {
+        throw InputFileError("ReactionRateFactory::newReactionRate", rate_node,
+            "Alternative units for 'length' or 'quantity` are not supported "
+            "when creating a standalone 'ReactionBase' object.");
+    }
+    return newReactionRate(rate_node, Units(1.));
+}
+
 std::string canonicalRateName(const std::string& type)
 {
     if (ReactionRateFactory::factory()->exists(type)) {