Merge pull request #650 from jkirk5/units

Added unit conversion capability to add_aviary_input, output, option

aviary/subsystems/mass/gasp_based/design_load.py

@@ -37,7 +37,7 @@ def setup(self):
 
         if self.options[Aircraft.Design.PART25_STRUCTURAL_CATEGORY] < 3:
 
-            add_aviary_input(self, Aircraft.Wing.LOADING, val=128)
+            add_aviary_input(self, Aircraft.Wing.LOADING, val=128, units='lbf/ft**2')
 
         self.add_output("max_airspeed", val=0, units="kn",
                         desc="VM0: maximum operating equivalent airspeed",
@@ -634,7 +634,9 @@ def setup(self):
         add_aviary_input(self, Aircraft.Wing.SWEEP, val=0.436, units="rad")
         add_aviary_input(self, Mission.Design.MACH, val=0.8)
 
-        add_aviary_output(self, Aircraft.Design.LIFT_CURVE_SLOPE, val=7.1765)
+        add_aviary_output(
+            self, Aircraft.Design.LIFT_CURVE_SLOPE, val=7.1765, units='1/rad'
+        )
 
         self.declare_partials(Aircraft.Design.LIFT_CURVE_SLOPE, "*")
 
@@ -673,7 +675,7 @@ def initialize(self):
 
     def setup(self):
 
-        add_aviary_input(self, Aircraft.Wing.LOADING, val=128)
+        add_aviary_input(self, Aircraft.Wing.LOADING, val=128, units='lbf/ft**2')
 
         self.add_input(
             "density_ratio",
@@ -695,8 +697,10 @@ def setup(self):
             desc="EMLF: maximum maneuver load factor, units are in g`s",
         )
 
-        add_aviary_input(self, Aircraft.Wing.AVERAGE_CHORD, val=12.6131)
-        add_aviary_input(self, Aircraft.Design.LIFT_CURVE_SLOPE, val=7.1765)
+        add_aviary_input(self, Aircraft.Wing.AVERAGE_CHORD, val=12.6131, units='ft')
+        add_aviary_input(
+            self, Aircraft.Design.LIFT_CURVE_SLOPE, val=7.1765, units='1/rad'
+        )
 
         add_aviary_output(self, Aircraft.Wing.ULTIMATE_LOAD_FACTOR, val=3.5)
 

aviary/variable_info/functions.py

@@ -35,7 +35,7 @@ def add_aviary_input(comp, varname, val=None, units=None, desc=None, shape_by_co
     val: float or ndarray
         Default value for variable.
     units: str
-        (Optional) when speficying val, units should also be specified.
+        (Optional) when specifying val, units should also be specified.
     desc: str
         (Optional) description text for the variable.
     shape_by_conn: bool
@@ -47,13 +47,16 @@ def add_aviary_input(comp, varname, val=None, units=None, desc=None, shape_by_co
         (Optional) shape for this input.
     """
     meta = meta_data[varname]
+    # units of None are overwritten with defaults. Overwriting units with None is
+    # unnecessary as it will cause errors down the line if the default is not already
+    # None
+    default_units = meta['units']
+
     if units:
         input_units = units
     else:
-        # units of None are overwritten with defaults. Overwriting units with None is
-        # unecessary as it will cause errors down the line if the default is not already
-        # None
-        input_units = meta['units']
+        input_units = default_units
+
     if desc:
         input_desc = desc
     else:
@@ -69,6 +72,18 @@ def add_aviary_input(comp, varname, val=None, units=None, desc=None, shape_by_co
                 val = np.zeros(shape)
             else:
                 val = np.ones(shape) * val
+
+        # val was not provided but different units were
+        if input_units != default_units:
+            try:
+                # convert the default units to requested units
+                val = convert_units(val, default_units, input_units)
+            except ValueError:
+                raise ValueError(
+                    f'The requested units {units} for input {varname} in component '
+                    f'{comp.name} are invalid.'
+                )
+
     comp.add_input(varname, val=val, units=input_units,
                    desc=input_desc, shape_by_conn=shape_by_conn, shape=shape)
 
@@ -104,13 +119,16 @@ def add_aviary_output(comp, varname, val=None, units=None, desc=None, shape_by_c
         (Optional) shape for this input.
     """
     meta = meta_data[varname]
+    # units of None are overwritten with defaults. Overwriting units with None is
+    # unnecessary as it will cause errors down the line if the default is not already
+    # None
+    default_units = meta['units']
+
     if units:
         output_units = units
     else:
-        # units of None are overwritten with defaults. Overwriting units with None is
-        # unecessary as it will cause errors down the line if the default is not already
-        # None
-        output_units = meta['units']
+        output_units = default_units
+
     if desc:
         output_desc = desc
     else:
@@ -126,6 +144,18 @@ def add_aviary_output(comp, varname, val=None, units=None, desc=None, shape_by_c
                 val = np.zeros(shape)
             else:
                 val = np.ones(shape) * val
+
+        # val was not provided but different units were
+        if output_units != default_units:
+            try:
+                # convert the default units to requested units
+                val = convert_units(val, default_units, output_units)
+            except ValueError:
+                raise ValueError(
+                    f'The requested units {units} for output {varname} in component '
+                    f'{comp.name} are invalid.'
+                )
+
     comp.add_output(varname, val=val, units=output_units,
                     desc=output_desc, shape_by_conn=shape_by_conn)
 
@@ -226,10 +256,18 @@ def add_aviary_option(comp, name, val=_unspecified, units=None, desc=None, meta_
         be used.
     """
     meta = meta_data[name]
+    # units of None are overwritten with defaults. Overwriting units with None is
+    # unnecessary as it will cause errors down the line if the default is not already
+    # None
+    default_units = meta['units']
+
+    if units:
+        option_units = units
+    else:
+        option_units = default_units
+
     if not desc:
         desc = meta['desc']
-    if val is _unspecified:
-        val = meta['default_value']
 
     types = meta['types']
     if meta['multivalue']:
@@ -238,6 +276,20 @@ def add_aviary_option(comp, name, val=_unspecified, units=None, desc=None, meta_
         else:
             types = (list, types)
 
+    if val is _unspecified:
+        val = meta['default_value']
+
+        # val was not provided but different units were
+        if option_units != default_units:
+            try:
+                # convert the default units to requested units
+                val = convert_units(val, default_units, option_units)
+            except ValueError:
+                raise ValueError(
+                    f'The requested units {units} for output {name} in component '
+                    f'{comp.name} are invalid.'
+                )
+
     if units not in [None, 'unitless']:
         types = tuple
         comp.options.declare(name, default=(val, units),

aviary/variable_info/test/test_functions.py

@@ -0,0 +1,63 @@
+import unittest
+import openmdao.api as om
+
+from aviary.utils.develop_metadata import add_meta_data
+from aviary.variable_info.functions import (
+    add_aviary_input,
+    add_aviary_output,
+    add_aviary_option,
+)
+from openmdao.utils.assert_utils import assert_near_equal
+
+
+class InputOutputOptionTest(unittest.TestCase):
+    """
+    Test the use of unit conversion when adding Aviary inputs, outputs, options
+    """
+
+    def test_unit_conversion(self):
+        comp = DummyComp()
+        prob = om.Problem()
+        prob.model.add_subsystem('comp', comp, promotes=['*'])
+        prob.setup()
+        prob.run_model()
+        tol = 1e-4  # whether or not a unit is converted does not need high tol
+        assert_near_equal(43.0556, prob.get_val('area'), tolerance=tol)
+        assert_near_equal(9.84252, prob.get_val('length_out'), tolerance=tol)
+        assert_near_equal(5000, prob.get_val('mass'), tolerance=tol)
+        assert_near_equal(11.0231, prob.get_val('mass_out'), tolerance=tol)
+
+
+class DummyComp(om.ExplicitComponent):
+    """
+    Simple component to test unit conversion
+    """
+
+    def initialize(self):
+        add_aviary_option(self, 'mass', units='lbm', meta_data=dummy_metadata)
+
+    def setup(self):
+        add_aviary_input(self, 'length', units='ft', meta_data=dummy_metadata)
+
+        add_aviary_output(self, 'area', units='ft**2', meta_data=dummy_metadata)
+        self.add_output('length_out', val=0)
+        add_aviary_output(self, 'mass', units='g', meta_data=dummy_metadata)
+        self.add_output('mass_out', val=0)
+
+    def compute(self, inputs, outputs):
+        mass = self.options['mass'][0]  # should be 5 kg -> lbm
+        length = inputs['length']  # should be 3 m -> ft
+
+        # outputs['area'] should default to 4 m**2 -> ft**2
+        outputs['length_out'] = length  # should return input 'length' in ft, NOT 3
+        # outputs['mass'] should default to 5 kg -> g
+        outputs['mass_out'] = mass  # should return option 'mass' in lbm, NOT 5
+
+
+dummy_metadata = {}
+add_meta_data('mass', dummy_metadata, units='kg', default_value=5)
+add_meta_data('length', dummy_metadata, units='m', default_value=3)
+add_meta_data('area', dummy_metadata, units='m**2', default_value=4)
+
+if __name__ == '__main__':
+    unittest.main()