[Reactor] Improve error message when advancing to past time

Resolves #1195
Cantera · Aug 4, 2023 · 3ec4577 · 3ec4577
1 parent 0b80608
commit 3ec4577
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diff --git a/src/numerics/CVodesIntegrator.cpp b/src/numerics/CVodesIntegrator.cpp
@@ -514,6 +514,11 @@ void CVodesIntegrator::integrate(double tout)
 {
     if (tout == m_time) {
         return;
+    } else if (tout < m_time) {
+        throw CanteraError("CVodesIntegrator::integrate",
+                           "Cannot integrate backwards in time.\n"
+                           "Requested time {} < current time {}",
+                           tout, m_time);
     }
     int nsteps = 0;
     while (m_tInteg < tout) {

diff --git a/src/numerics/IdasIntegrator.cpp b/src/numerics/IdasIntegrator.cpp
@@ -453,6 +453,11 @@ void IdasIntegrator::integrate(double tout)
 {
     if (tout == m_time) {
         return;
+    } else if (tout < m_time) {
+        throw CanteraError("IdasIntegrator::integrate",
+                           "Cannot integrate backwards in time.\n"
+                           "Requested time {} < current time {}",
+                           tout, m_time);
     }
     int nsteps = 0;
     while (m_tInteg < tout) {

diff --git a/test/python/test_reactor.py b/test/python/test_reactor.py
@@ -348,6 +348,12 @@ def test_advance_limits_invalid(self):
         with pytest.raises(ct.CanteraError, match="No component named 'spam'"):
             self.r1.set_advance_limit("spam", 0.1)
 
+    def test_advance_reverse(self):
+        self.make_reactors(n_reactors=1)
+        self.net.advance(0.1)
+        with pytest.raises(ct.CanteraError, match="backwards in time"):
+            self.net.advance(0.09)
+
     def test_heat_transfer2(self):
         # Result should be the same if (m * cp) / (U * A) is held constant
         self.make_reactors(T1=300, T2=1000)
@@ -1531,6 +1537,15 @@ def make_reactors(self, gas, surf):
         sim = ct.ReactorNet([r])
         return r, rsurf, sim
 
+    def test_advance_reverse(self):
+        surf, gas = self.import_phases()
+        gas.TPX = 1500, 4000, 'NH3:1.0, SiF4:0.4'
+        r, rsurf, sim = self.make_reactors(gas, surf)
+
+        sim.advance(0.1)
+        with pytest.raises(ct.CanteraError, match="backwards in time"):
+            sim.advance(0.09)
+
     def test_no_mass_flow_rate(self):
         surf, gas = self.import_phases()
         r = ct.FlowReactor(gas)