Added capability for IVCs to be instantiated with a list of variables

openmdao/core/indepvarcomp.py

@@ -14,13 +14,17 @@ class IndepVarComp(ExplicitComponent):
 
     Parameters
     ----------
-    name : str or None
-        Name of the variable.
+    name : str, list, tuple, or None
+        Name of the variable or list/tuple of variables.
+        If a string, defines a single variable with the specified name.
+        If a list or tuple, each element should be a tuple with the format (name, value) or 
+        (name, value, kwargs) where `name` is a string, `value` can be any type compatible with val,
+        and `kwargs` is a dictionary of keyword arguments.
         If None, variables should be defined external to this class by calling add_output.
     val : float or ndarray
-        Value of the variable if a single variable is being defined.
+        Initial value of the variable if a single variable is being defined.
     **kwargs : dict
-        Keyword arguments.
+        Additional keyword arguments.
     """
 
     def __init__(self, name=None, val=1.0, **kwargs):
@@ -39,6 +43,28 @@ def __init__(self, name=None, val=1.0, **kwargs):
         if isinstance(name, str):
             super().add_output(name, val, **kwargs)
 
+        elif isinstance(name, (list, tuple)):
+            for tup in name:
+                if not isinstance(tup, tuple):
+                    raise TypeError("Each entry in the list of tuples must be of type tuple.")
+                if len(tup) == 2:
+                    if not isinstance(tup[0], str):
+                        raise TypeError("The first element of the tuple must be a string representing the variable name.")
+                    if not isinstance(tup[1], (int, float, list, tuple, np.ndarray)):
+                        raise TypeError("The second element of the tuple must be the initial value of the variable.")
+                    super().add_output(tup[0], tup[1], **kwargs)
+                elif len(tup) == 3:
+                    if not isinstance(tup[0], str):
+                        raise TypeError("The first element of the tuple must be a string representing the variable name.")
+                    if not isinstance(tup[1], (int, float, list, tuple, np.ndarray)):
+                        raise TypeError("The second element of the tuple must be the initial value of the variable.")
+                    if not isinstance(tup[2], dict):
+                        raise TypeError("The third element of the tuple must be a dictionary of keyword arguments.")
+                    super().add_output(tup[0], tup[1], **tup[2])
+                else:
+                    raise ValueError("Each entry in the list of tuples must be of the form "
+                                     "(name, value) or (name, value, keyword_dict).")
+
         elif name is None:
             pass
 

openmdao/core/tests/test_indep_var_comp.py

@@ -105,6 +105,52 @@ def test_add_output(self):
         assert_near_equal(prob.get_val('indep_var_1'), 1.0)
         assert_near_equal(prob.get_val('indep_var_2'), 2.0)
 
+    def test_tuple_ivc(self):
+        """Define one independent variable using a tuple."""
+
+        ivcs = [
+            ('indep_var', 1.0),
+            ('indep_var2', 2.0),
+        ]
+
+        comp = om.IndepVarComp(ivcs)
+
+        prob = om.Problem()
+        prob.model.add_subsystem('comp', comp, promotes=['*'])
+        prob.setup(check=False)
+
+        assert_near_equal(prob.get_val('indep_var'), 1.0)
+        assert_near_equal(prob.get_val('indep_var2'), 2.0)
+
+    def test_tuple_ivc_kwargs(self):
+        """Define one independent variable using a tuple with additional options."""
+
+        ivcs = [
+            ('indep_var', 1.0, {'units': 'm'}),
+            ('indep_var2', 2.0, {'units': 'm'}),
+        ]
+
+        comp = om.IndepVarComp(ivcs)
+
+        prob = om.Problem()
+        prob.model.add_subsystem('comp', comp, promotes=['*'])
+        prob.setup(check=False)
+
+        assert_near_equal(prob.get_val('indep_var', units='m'), 1.0)
+        assert_near_equal(prob.get_val('indep_var2', units='m'), 2.0)
+
+    def test_tuple_error(self):
+        """Test to see if the objects in the list are actually tuples."""
+
+        ivcs = ['indep_var', 'indep_var2']
+
+        try:
+            om.IndepVarComp(ivcs)
+        except TypeError as err:
+            self.assertEqual(str(err), "Each entry in the list of tuples must be of type tuple.")
+        else:
+            self.fail('Exception expected.')
+
     def test_promote_glob_no_inputs(self):
         p = om.Problem()
         p.model.add_subsystem('indep',