Expose getting/setting of max-steps to python interface & test

include/cantera/numerics/CVodesIntegrator.h

@@ -53,6 +53,7 @@ public:
     virtual void setMaxStepSize(double hmax);
     virtual void setMinStepSize(double hmin);
     virtual void setMaxSteps(int nmax);
+    virtual int maxSteps();
     virtual void setMaxErrTestFails(int n);
     virtual void setBandwidth(int N_Upper, int N_Lower) {
         m_mupper = N_Upper;

include/cantera/numerics/Integrator.h

@@ -183,10 +183,21 @@ public:
         warn("setMaxErrTestFails");
     }
 
+    //! Set the maximum number of time-steps the integrator can take
+    //!  before reaching the next output time
+    //!  @param nmax The maximum number of steps, setting this value
+    //!              to zero disables this option.
     virtual void setMaxSteps(int nmax) {
         warn("setMaxStep");
     }
 
+    //! Returns the maximum number of time-steps the integrator can take
+    //!  before reaching the next output time
+    virtual int maxSteps() {
+        warn("maxSteps");
+        return 0;
+    }
+
     virtual void setBandwidth(int N_Upper, int N_Lower) {
         warn("setBandwidth");
     }

include/cantera/zeroD/ReactorNet.h

@@ -207,6 +207,21 @@ public:
         m_integrator_init = false;
     }
 
+    //! Set the maximum number of internal integration time-steps the
+    //! integrator will take before reaching the next output time
+    //! @param nmax The maximum number of steps, setting this value
+    //!             to zero disables this option.
+    virtual void setMaxSteps(int nmax) {
+        m_integ->setMaxSteps(nmax);
+    }
+
+    //! Returns the maximum number of internal integration time-steps the
+    //!  integrator will take before reaching the next output time
+    //!
+    virtual int maxSteps() {
+        return m_integ->maxSteps();
+    }
+
 protected:
     //! Initialize the reactor network. Called automatically the first time
     //! advance or step is called.

interfaces/cython/cantera/_cantera.pxd

@@ -579,6 +579,8 @@ cdef extern from "cantera/zeroD/ReactorNet.h":
         double atol()
         void setMaxTimeStep(double)
         void setMaxErrTestFails(int)
+        void setMaxSteps(int)
+        int maxSteps()
         cbool verbose()
         void setVerbose(cbool)
         size_t neq()

interfaces/cython/cantera/reactor.pyx

@@ -896,6 +896,16 @@ cdef class ReactorNet:
         def __set__(self, n):
             self.net.setMaxErrTestFails(n)
 
+    property max_steps:
+        """
+        The maximum number of internal integration time-steps that CVODES
+        is allowed to take before reaching the next output time.
+        """
+        def __set__(self, nsteps):
+            self.net.setMaxSteps(nsteps)
+        def __get__(self):
+            return self.net.maxSteps()
+
     property rtol:
         """
         The relative error tolerance used while integrating the reactor

interfaces/cython/cantera/test/test_reactor.py

@@ -140,6 +140,22 @@ class TestReactor(utilities.CanteraTest):
 
         #self.assertNear(self.net.time, tEnd)
 
+    def test_maxsteps(self):
+        self.make_reactors()
+
+        # set the up a case where we can't take
+        # enough time-steps to reach the endtime
+        max_steps = 10
+        max_step_size = 1e-07
+        self.net.set_initial_time(0)
+        self.net.set_max_time_step(max_step_size)
+        self.net.max_steps = max_steps
+        with self.assertRaisesRegex(
+                ct.CanteraError, 'mxstep steps taken before reaching tout'):
+            self.net.advance(1e-04)
+        self.assertLessEqual(self.net.time, max_steps * max_step_size)
+        self.assertEqual(self.net.max_steps, max_steps)
+
     def test_equalize_pressure(self):
         self.make_reactors(P1=101325, P2=300000)
         self.add_wall(K=0.1, A=1.0)

src/numerics/CVodesIntegrator.cpp

@@ -210,6 +210,11 @@ void CVodesIntegrator::setMaxSteps(int nmax)
     }
 }
 
+int CVodesIntegrator::maxSteps()
+{
+    return m_maxsteps;
+}
+
 void CVodesIntegrator::setMaxErrTestFails(int n)
 {
     m_maxErrTestFails = n;