Support class parameters for attrs

floris/simulation/base.py

@@ -26,8 +26,10 @@
 )
 
 from attrs import (
+    Attribute,
     asdict,
     define,
+    field,
     fields,
 )
 
@@ -47,8 +49,9 @@ class BaseClass(LoggerBase, FromDictMixin):
     BaseClass object class. This class does the logging and MixIn class inheritance.
     """
 
-    state = State.UNINITIALIZED
-
+    # Initialize `state` and ensure it is treated as an attribute rather than a constant parameter.
+    # See https://www.attrs.org/en/stable/api-attr.html#attr.ib
+    state = field(init=False, default=State.UNINITIALIZED)  
 
     @classmethod
     def get_model_defaults(cls) -> Dict[str, Any]:
@@ -74,13 +77,17 @@ def _get_model_dict(self) -> dict:
 
 
 @define
-class BaseModel(BaseClass, ABC):
+class BaseModel(BaseClass):
     """
     BaseModel is the generic class for any wake models. It defines the API required to
     create a valid model.
     """
 
-    NUM_EPS: Final[float] = 0.001  # This is a numerical epsilon to prevent divide by zeros
+    NUM_EPS: Final[float] = field(init=False, default=0.001)  # This is a numerical epsilon to prevent divide by zeros
+
+    @NUM_EPS.validator
+    def lock_num_eps(self, attribute: Attribute, value: Any) -> None:
+        assert value == 0.001  # Locks NUM_EPS to a fixed value. You shouldn't change this!
 
     @abstractmethod
     def prepare_function() -> dict:

floris/simulation/wake_deflection/gauss.py

@@ -16,7 +16,7 @@
 
 import numexpr as ne
 import numpy as np
-from attrs import define, field
+from attrs import define, field, fields
 from numpy import pi
 
 from floris.simulation import (
@@ -28,6 +28,7 @@
 )
 from floris.utilities import cosd, sind
 
+NUM_EPS = fields(BaseModel).NUM_EPS.default
 
 @define
 class GaussVelocityDeflection(BaseModel):
@@ -309,11 +310,11 @@ def wake_added_yaw(
     ### compute the spanwise and vertical velocities induced by yaw
 
     # decay = eps ** 2 / (4 * nu * delta_x / Uinf + eps ** 2)   # This is the decay downstream
-    yLocs = delta_y + BaseModel.NUM_EPS
+    yLocs = delta_y + NUM_EPS
 
     # top vortex
     # NOTE: this is the top of the grid, not the top of the rotor
-    zT = z_i - (HH + D / 2) + BaseModel.NUM_EPS  # distance from the top of the grid
+    zT = z_i - (HH + D / 2) + NUM_EPS  # distance from the top of the grid
     rT = ne.evaluate("yLocs ** 2 + zT ** 2")  # TODO: This is (-) in the paper
     # This looks like spanwise decay;
     # it defines the vortex profile in the spanwise directions
@@ -323,15 +324,15 @@ def wake_added_yaw(
     # w_top = (-1 * Gamma_top * yLocs) / (2 * pi * rT) * core_shape * decay
 
     # bottom vortex
-    zB = z_i - (HH - D / 2) + BaseModel.NUM_EPS
+    zB = z_i - (HH - D / 2) + NUM_EPS
     rB = ne.evaluate("yLocs ** 2 + zB ** 2")
     core_shape = ne.evaluate("1 - exp(-rB / (eps ** 2))")
     v_bottom = ne.evaluate("(Gamma_bottom * zB) / (2 * pi * rB) * core_shape")
     v_bottom = np.mean( v_bottom, axis=(3,4) )
     # w_bottom = (-1 * Gamma_bottom * yLocs) / (2 * pi * rB) * core_shape * decay
 
     # wake rotation vortex
-    zC = z_i - HH + BaseModel.NUM_EPS
+    zC = z_i - HH + NUM_EPS
     rC = ne.evaluate("yLocs ** 2 + zC ** 2")
     core_shape = ne.evaluate("1 - exp(-rC / (eps ** 2))")
     v_core = ne.evaluate("(Gamma_wake_rotation * zC) / (2 * pi * rC) * core_shape")
@@ -411,10 +412,10 @@ def calculate_transverse_velocity(
 
     # This is the decay downstream
     decay = ne.evaluate("eps ** 2 / (4 * nu * delta_x / Uinf + eps ** 2)")
-    yLocs = delta_y + BaseModel.NUM_EPS
+    yLocs = delta_y + NUM_EPS
 
     # top vortex
-    zT = z - (HH + D / 2) + BaseModel.NUM_EPS
+    zT = z - (HH + D / 2) + NUM_EPS
     rT = ne.evaluate("yLocs ** 2 + zT ** 2")  # TODO: This is - in the paper
     # This looks like spanwise decay;
     # it defines the vortex profile in the spanwise directions
@@ -423,14 +424,14 @@ def calculate_transverse_velocity(
     W1 = ne.evaluate("(-1 * Gamma_top * yLocs) / (2 * pi * rT) * core_shape * decay")
 
     # bottom vortex
-    zB = z - (HH - D / 2) + BaseModel.NUM_EPS
+    zB = z - (HH - D / 2) + NUM_EPS
     rB = ne.evaluate("yLocs ** 2 + zB ** 2")
     core_shape = ne.evaluate("1 - exp(-rB / (eps ** 2))")
     V2 = ne.evaluate("(Gamma_bottom * zB) / (2 * pi * rB) * core_shape * decay")
     W2 = ne.evaluate("(-1 * Gamma_bottom * yLocs) / (2 * pi * rB) * core_shape * decay")
 
     # wake rotation vortex
-    zC = z - HH + BaseModel.NUM_EPS
+    zC = z - HH + NUM_EPS
     rC = ne.evaluate("yLocs ** 2 + zC ** 2")
     core_shape = ne.evaluate("1 - exp(-rC / (eps ** 2))")
     V5 = ne.evaluate("(Gamma_wake_rotation * zC) / (2 * pi * rC) * core_shape * decay")
@@ -439,7 +440,7 @@ def calculate_transverse_velocity(
     ### Boundary condition - ground mirror vortex
 
     # top vortex - ground
-    zTb = z + (HH + D / 2) + BaseModel.NUM_EPS
+    zTb = z + (HH + D / 2) + NUM_EPS
     rTb = ne.evaluate("yLocs ** 2 + zTb ** 2")
     # This looks like spanwise decay;
     # it defines the vortex profile in the spanwise directions
@@ -448,14 +449,14 @@ def calculate_transverse_velocity(
     W3 = ne.evaluate("(Gamma_top * yLocs) / (2 * pi * rTb) * core_shape * decay")
 
     # bottom vortex - ground
-    zBb = z + (HH - D / 2) + BaseModel.NUM_EPS
+    zBb = z + (HH - D / 2) + NUM_EPS
     rBb = ne.evaluate("yLocs ** 2 + zBb ** 2")
     core_shape = ne.evaluate("1 - exp(-rBb / (eps ** 2))")
     V4 = ne.evaluate("(-1 * Gamma_bottom * zBb) / (2 * pi * rBb) * core_shape * decay")
     W4 = ne.evaluate("(Gamma_bottom * yLocs) / (2 * pi * rBb) * core_shape * decay")
 
     # wake rotation vortex - ground effect
-    zCb = z + HH + BaseModel.NUM_EPS
+    zCb = z + HH + NUM_EPS
     rCb = ne.evaluate("yLocs ** 2 + zCb ** 2")
     core_shape = ne.evaluate("1 - exp(-rCb / (eps ** 2))")
     V6 = ne.evaluate("(-1 * Gamma_wake_rotation * zCb) / (2 * pi * rCb) * core_shape * decay")

floris/simulation/wake_velocity/jensen.py

@@ -14,7 +14,7 @@
 
 import numexpr as ne
 import numpy as np
-from attrs import define, field
+from attrs import define, field, fields
 
 from floris.simulation import (
     BaseModel,
@@ -24,6 +24,7 @@
     Turbine,
 )
 
+NUM_EPS = fields(BaseModel).NUM_EPS.default
 
 @define
 class JensenVelocityDeficit(BaseModel):
@@ -107,7 +108,6 @@ def function(
         dz = ne.evaluate("z - z_i")
 
         we = self.we
-        NUM_EPS = JensenVelocityDeficit.NUM_EPS
 
         # Construct a boolean mask to include all points downstream of the turbine
         downstream_mask = ne.evaluate("dx > 0 + NUM_EPS")

tests/base_test.py

@@ -35,22 +35,31 @@ def test_get_model_defaults():
     """
     This tests that the default parameter values are set correctly and unchanged if not
     explicitly set.
-    Note that NUM_EPS in BaseModel is treated as a default parameter by attrs.
+    Note that state and NUM_EPS in BaseClass and BaseModel are treated as default parameters
+    by attrs.
     """
     defaults = ClassTest.get_model_defaults()
-    assert len(defaults) == 3
+    assert len(defaults) == 4
     assert defaults["x"] == 1
     assert defaults["a_string"] == "abc"
 
 
 def test_get_model_values():
     """
     This tests that the parameters are changed when set by the user.
-    Note that NUM_EPS in BaseModel is treated as a parameter by attrs. It isn't changed
-    in the instantiation method, but it is still included as the parameter set.
+    Note that state and NUM_EPS in BaseClass and BaseModel are treated as parameters by attrs.
+    They aren't changed in the instantiation method, but they are still included in the
+    parameter set.
     """
     cls = ClassTest(x=4, a_string="xyz")
     values = cls._get_model_dict()
-    assert len(values) == 3
+    assert len(values) == 4
     assert values["x"] == 4
     assert values["a_string"] == "xyz"
+
+def test_NUM_EPS():
+    cls = ClassTest(x=4, a_string="xyz")
+    assert cls.NUM_EPS == 0.001
+
+    with pytest.raises(AssertionError):
+        cls.NUM_EPS = 2