Merge pull request #343 from Kenneth-T-Moore/ken3

Guess nonlinear needs to behave like a NonlinearRunOnce iteration and do data-passing between components after each call to guess.

openmdao/core/component.py

@@ -792,3 +792,11 @@ def _set_partials_meta(self):
 
         for approx in itervalues(self._approx_schemes):
             approx._init_approximations()
+
+    def _guess_nonlinear(self):
+        """
+        Provide initial guess for states.
+
+        Does nothing on any non-implicit component.
+        """
+        pass

openmdao/core/group.py

@@ -102,6 +102,9 @@ def _configure(self):
         for subsys in self._subsystems_myproc:
             subsys._configure()
 
+            if subsys._has_guess:
+                self._has_guess = True
+
         self.configure()
 
     def _setup_procs(self, pathname, comm):
@@ -1267,20 +1270,21 @@ def _solve_nonlinear(self):
 
         name = self.pathname if self.pathname else 'root'
 
-        # Execute guess_nonlinear if specified.
-        # We need to call this early enough so that any solver that needs initial guesses has
-        # them.
-        # TODO: It is pointless to run this ahead of non-iterative solvers.
-        for sub in self.system_iter(recurse=True):
-            if hasattr(sub, 'guess_nonlinear'):
-                with sub._unscaled_context(outputs=[sub._outputs], residuals=[sub._residuals]):
-                    sub.guess_nonlinear(sub._inputs, sub._outputs, sub._residuals)
-
         with Recording(name + '._solve_nonlinear', self.iter_count, self):
             result = self._nonlinear_solver.solve()
 
         return result
 
+    def _guess_nonlinear(self):
+        """
+        Provide initial guess for states.
+        """
+        if self._has_guess:
+            for isub, sub in enumerate(self._subsystems_myproc):
+                if sub._has_guess:
+                    self._transfer('nonlinear', 'fwd', isub)
+                    sub._guess_nonlinear()
+
     def _apply_linear(self, vec_names, mode, scope_out=None, scope_in=None):
         """
         Compute jac-vec product. The model is assumed to be in a scaled state.

openmdao/core/implicitcomponent.py

@@ -26,6 +26,15 @@ def __init__(self, **kwargs):
         """
         super(ImplicitComponent, self).__init__(**kwargs)
 
+        if overrides_method('guess_nonlinear', self, ImplicitComponent):
+            self._has_guess = True
+
+    def _configure(self):
+        """
+        Configure this system to assign children settings.
+
+        Also tag component if it provides a guess_nonlinear.
+        """
         if overrides_method('apply_linear', self, ImplicitComponent):
             self.matrix_free = True
 
@@ -71,6 +80,13 @@ def _solve_nonlinear(self):
             else:
                 return result
 
+    def _guess_nonlinear(self):
+        """
+        Provide initial guess for states.
+        """
+        with self._unscaled_context(outputs=[self._outputs], residuals=[self._residuals]):
+            self.guess_nonlinear(self._inputs, self._outputs, self._residuals)
+
     def _apply_linear(self, vec_names, mode, scope_out=None, scope_in=None):
         """
         Compute jac-vec product. The model is assumed to be in a scaled state.

openmdao/core/system.py

@@ -237,6 +237,9 @@ class System(object):
     #
     _reconfigured : bool
         If True, this system has reconfigured, and the immediate parent should update.
+    #
+    _has_guess : bool
+        True if this system has or contains a system with a `guess_nonlinear` method defined.
     """
 
     def __init__(self, **kwargs):
@@ -344,6 +347,8 @@ def __init__(self, **kwargs):
         self.initialize()
         self.metadata.update(kwargs)
 
+        self._has_guess = False
+
     def _check_reconf(self):
         """
         Check if this systems wants to reconfigure and if so, perform the reconfiguration.

openmdao/core/tests/test_impl_comp.py

@@ -16,8 +16,8 @@
 class QuadraticComp(ImplicitComponent):
     """
     A Simple Implicit Component representing a Quadratic Equation.
-    
-    R(a, b, c, x) = ax^2 + bx + c 
+
+    R(a, b, c, x) = ax^2 + bx + c
 
     Solution via Quadratic Formula:
     x = (-b + sqrt(b^2 - 4ac)) / 2a
@@ -286,6 +286,134 @@ def guess_nonlinear(self, inputs, outputs, resids):
         prob.run_model()
         assert_rel_error(self, prob['comp2.x'], 3.)
 
+    def test_guess_nonlinear_transfer(self):
+        # Test that data is transfered to a component before calling guess_nonlinear.
+
+        class ImpWithInitial(ImplicitComponent):
+
+            def setup(self):
+                self.add_input('x', 3.0)
+                self.add_output('y', 4.0)
+
+            def solve_nonlinear(self, inputs, outputs):
+                """ Do nothing. """
+                pass
+
+            def apply_nonlinear(self, inputs, outputs, resids):
+                """ Do nothing. """
+                pass
+
+            def guess_nonlinear(self, inputs, outputs, resids):
+                # Passthrough
+                outputs['y'] = inputs['x']
+
+
+        group = Group()
+
+        group.add_subsystem('px', IndepVarComp('x', 77.0))
+        group.add_subsystem('comp1', ImpWithInitial())
+        group.add_subsystem('comp2', ImpWithInitial())
+        group.connect('px.x', 'comp1.x')
+        group.connect('comp1.y', 'comp2.x')
+
+        group.nonlinear_solver = NewtonSolver()
+        group.nonlinear_solver.options['maxiter'] = 1
+
+        prob = Problem(model=group)
+        prob.set_solver_print(level=0)
+        prob.setup(check=False)
+
+        prob.run_model()
+        assert_rel_error(self, prob['comp2.y'], 77., 1e-5)
+
+    def test_guess_nonlinear_transfer_subbed(self):
+        # Test that data is transfered to a component before calling guess_nonlinear.
+
+        class ImpWithInitial(ImplicitComponent):
+
+            def setup(self):
+                self.add_input('x', 3.0)
+                self.add_output('y', 4.0)
+
+            def solve_nonlinear(self, inputs, outputs):
+                """ Do nothing. """
+                pass
+
+            def apply_nonlinear(self, inputs, outputs, resids):
+                """ Do nothing. """
+                resids['y'] = 1.0e-6
+                pass
+
+            def guess_nonlinear(self, inputs, outputs, resids):
+                # Passthrough
+                outputs['y'] = inputs['x']
+
+
+        group = Group()
+        sub = Group()
+
+        group.add_subsystem('px', IndepVarComp('x', 77.0))
+        sub.add_subsystem('comp1', ImpWithInitial())
+        sub.add_subsystem('comp2', ImpWithInitial())
+        group.connect('px.x', 'sub.comp1.x')
+        group.connect('sub.comp1.y', 'sub.comp2.x')
+
+        group.add_subsystem('sub', sub)
+
+        group.nonlinear_solver = NewtonSolver()
+        group.nonlinear_solver.options['maxiter'] = 1
+
+        prob = Problem(model=group)
+        prob.set_solver_print(level=0)
+        prob.setup(check=False)
+
+        prob.run_model()
+        assert_rel_error(self, prob['sub.comp2.y'], 77., 1e-5)
+
+    def test_guess_nonlinear_transfer_subbed2(self):
+        # Test that data is transfered to a component before calling guess_nonlinear.
+
+        class ImpWithInitial(ImplicitComponent):
+
+            def setup(self):
+                self.add_input('x', 3.0)
+                self.add_output('y', 4.0)
+
+            def solve_nonlinear(self, inputs, outputs):
+                """ Do nothing. """
+                pass
+
+            def apply_nonlinear(self, inputs, outputs, resids):
+                """ Do nothing. """
+                resids['y'] = 1.0e-6
+                pass
+
+            def guess_nonlinear(self, inputs, outputs, resids):
+                # Passthrough
+                outputs['y'] = inputs['x']
+
+
+        group = Group()
+        sub = Group()
+
+        group.add_subsystem('px', IndepVarComp('x', 77.0))
+        sub.add_subsystem('comp1', ImpWithInitial())
+        sub.add_subsystem('comp2', ImpWithInitial())
+        group.connect('px.x', 'sub.comp1.x')
+        group.connect('sub.comp1.y', 'sub.comp2.x')
+
+        group.add_subsystem('sub', sub)
+
+        sub.nonlinear_solver = NewtonSolver()
+        sub.nonlinear_solver.options['maxiter'] = 1
+
+        prob = Problem(model=group)
+        prob.set_solver_print(level=0)
+        prob.setup(check=False)
+
+        prob.run_model()
+        assert_rel_error(self, prob['sub.comp2.y'], 77., 1e-5)
+
     def test_guess_nonlinear_feature(self):
 
         class ImpWithInitial(ImplicitComponent):

openmdao/solvers/nonlinear/newton.py

@@ -182,10 +182,11 @@ def _iter_initialize(self):
         float
             error at the first iteration.
         """
+        system = self._system
+
         with Recording('Newton_subsolve', 0, self):
             if self.options['solve_subsystems'] and \
                (self._iter_count <= self.options['max_sub_solves']):
-                system = self._system
 
                 self._solver_info.prefix += '+  '
 
@@ -201,6 +202,10 @@ def _iter_initialize(self):
                 self._solver_info.prefix = self._solver_info.prefix[:-3]
 
         if self.options['maxiter'] > 0:
+
+            # Execute guess_nonlinear if specified.
+            system._guess_nonlinear()
+
             self._run_apply()
             norm = self._iter_get_norm()
         else: