Add equality operator for URDF model

CHANGELOG.md

@@ -1,7 +1,8 @@
 # Changelog
 
-## Version 0.0.45 (development)
+## Version 0.0.45 (upcoming, development)
 - Upgrade to trimesh version 3.11.2
+- Add `__eq__` operator to URDF based on equality of individual elements (order-invariant)
 
 ## Version 0.0.44 (development)
 - Parse and write `name` attribute of `material` element 

src/yourdfpy/urdf.py

@@ -1,5 +1,4 @@
 import os
-from numpy.lib.npyio import load
 import six
 import copy
 import logging
@@ -16,27 +15,85 @@
 _logger = logging.getLogger(__name__)
 
 
-@dataclass
+def _array_eq(arr1, arr2):
+    if arr1 is None and arr2 is None:
+        return True
+    return (
+        isinstance(arr1, np.ndarray)
+        and isinstance(arr2, np.ndarray)
+        and arr1.shape == arr2.shape
+        and (arr1 == arr2).all()
+    )
+
+
+@dataclass(eq=False)
 class TransmissionJoint:
     name: str
     hardware_interfaces: List[str] = field(default_factory=list)
 
+    def __eq__(self, other):
+        if not isinstance(other, TransmissionJoint):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and all(
+                self_hi in other.hardware_interfaces
+                for self_hi in self.hardware_interfaces
+            )
+            and all(
+                other_hi in self.hardware_interfaces
+                for other_hi in other.hardware_interfaces
+            )
+        )
 
-@dataclass
+
+@dataclass(eq=False)
 class Actuator:
     name: str
     mechanical_reduction: Optional[float] = None
     # The follwing is only valid for ROS Indigo and prior versions
     hardware_interfaces: List[str] = field(default_factory=list)
 
+    def __eq__(self, other):
+        if not isinstance(other, Actuator):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and self.mechanical_reduction == other.mechanical_reduction
+            and all(
+                self_hi in other.hardware_interfaces
+                for self_hi in self.hardware_interfaces
+            )
+            and all(
+                other_hi in self.hardware_interfaces
+                for other_hi in other.hardware_interfaces
+            )
+        )
+
 
-@dataclass
+@dataclass(eq=False)
 class Transmission:
     name: str
     type: Optional[str] = None
     joints: List[TransmissionJoint] = field(default_factory=list)
     actuators: List[Actuator] = field(default_factory=list)
 
+    def __eq__(self, other):
+        if not isinstance(other, Transmission):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and self.type == other.type
+            and all(self_joint in other.joints for self_joint in self.joints)
+            and all(other_joint in self.joints for other_joint in other.joints)
+            and all(
+                self_actuator in other.actuators for self_actuator in self.actuators
+            )
+            and all(
+                other_actuator in self.actuators for other_actuator in other.actuators
+            )
+        )
+
 
 @dataclass
 class Calibration:
@@ -70,16 +127,33 @@ class Cylinder:
     length: float
 
 
-@dataclass
+@dataclass(eq=False)
 class Box:
     size: np.ndarray
 
+    def __eq__(self, other):
+        if not isinstance(other, Box):
+            return NotImplemented
+        return _array_eq(self.size, other.size)
 
-@dataclass
+
+@dataclass(eq=False)
 class Mesh:
     filename: str
     scale: Optional[Union[float, np.ndarray]] = None
 
+    def __eq__(self, other):
+        if not isinstance(other, Mesh):
+            return NotImplemented
+
+        if self.filename != other.filename:
+            return False
+
+        if isinstance(self.scale, float) and isinstance(other.scale, float):
+            return self.scale == other.scale
+
+        return _array_eq(self.scale, other.scale)
+
 
 @dataclass
 class Geometry:
@@ -89,10 +163,15 @@ class Geometry:
     mesh: Optional[Mesh] = None
 
 
-@dataclass
+@dataclass(eq=False)
 class Color:
     rgba: np.ndarray
 
+    def __eq__(self, other):
+        if not isinstance(other, Color):
+            return NotImplemented
+        return _array_eq(self.rgba, other.rgba)
+
 
 @dataclass
 class Texture:
@@ -106,35 +185,80 @@ class Material:
     texture: Optional[Texture] = None
 
 
-@dataclass
+@dataclass(eq=False)
 class Visual:
     name: Optional[str] = None
     origin: Optional[np.ndarray] = None
     geometry: Optional[Geometry] = None  # That's not really optional according to ROS
     material: Optional[Material] = None
 
+    def __eq__(self, other):
+        if not isinstance(other, Visual):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and _array_eq(self.origin, other.origin)
+            and self.geometry == other.geometry
+            and self.material == other.material
+        )
 
-@dataclass
+
+@dataclass(eq=False)
 class Collision:
     name: str
     origin: Optional[np.ndarray] = None
     geometry: Geometry = None
 
+    def __eq__(self, other):
+        if not isinstance(other, Collision):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and _array_eq(self.origin, other.origin)
+            and self.geometry == other.geometry
+        )
 
-@dataclass
+
+@dataclass(eq=False)
 class Inertial:
     origin: Optional[np.ndarray] = None
     mass: Optional[float] = None
     inertia: Optional[np.ndarray] = None
 
+    def __eq__(self, other):
+        if not isinstance(other, Inertial):
+            return NotImplemented
+        return (
+            _array_eq(self.origin, other.origin)
+            and self.mass == other.mass
+            and _array_eq(self.inertia, other.inertia)
+        )
+
 
-@dataclass
+@dataclass(eq=False)
 class Link:
     name: str
     inertial: Optional[Inertial] = None
     visuals: List[Visual] = field(default_factory=list)
     collisions: List[Collision] = field(default_factory=list)
 
+    def __eq__(self, other):
+        if not isinstance(other, Link):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and self.inertial == other.inertial
+            and all(self_visual in other.visuals for self_visual in self.visuals)
+            and all(other_visual in self.visuals for other_visual in other.visuals)
+            and all(
+                self_collision in other.collisions for self_collision in self.collisions
+            )
+            and all(
+                other_collision in self.collisions
+                for other_collision in other.collisions
+            )
+        )
+
 
 @dataclass
 class Dynamics:
@@ -150,7 +274,7 @@ class Limit:
     upper: Optional[float] = None
 
 
-@dataclass
+@dataclass(eq=False)
 class Joint:
     name: str
     type: str = None
@@ -164,15 +288,53 @@ class Joint:
     calibration: Optional[Calibration] = None
     safety_controller: Optional[SafetyController] = None
 
+    def __eq__(self, other):
+        if not isinstance(other, Joint):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and self.type == other.type
+            and self.parent == other.parent
+            and self.child == other.child
+            and _array_eq(self.origin, other.origin)
+            and _array_eq(self.axis, other.axis)
+            and self.dynamics == other.dynamics
+            and self.limit == other.limit
+            and self.mimic == other.mimic
+            and self.calibration == other.calibration
+            and self.safety_controller == other.safety_controller
+        )
 
-@dataclass
+
+@dataclass(eq=False)
 class Robot:
     name: str
     links: List[Link] = field(default_factory=list)
     joints: List[Joint] = field(default_factory=list)
     transmission: List[str] = field(default_factory=list)
     gazebo: List[str] = field(default_factory=list)
 
+    def __eq__(self, other):
+        if not isinstance(other, Robot):
+            return NotImplemented
+        return (
+            self.name == other.name
+            and all(self_link in other.links for self_link in self.links)
+            and all(other_link in self.links for other_link in other.links)
+            and all(self_joint in other.joints for self_joint in self.joints)
+            and all(other_joint in self.joints for other_joint in other.joints)
+            and all(
+                self_transmission in other.transmission
+                for self_transmission in self.transmission
+            )
+            and all(
+                other_transmission in self.transmission
+                for other_transmission in other.transmission
+            )
+            and all(self_gazebo in other.gazebo for self_gazebo in self.gazebo)
+            and all(other_gazebo in self.gazebo for other_gazebo in other.gazebo)
+        )
+
 
 class URDFError(Exception):
     """General URDF exception."""
@@ -1982,3 +2144,8 @@ def _write_robot(self, robot):
             self._write_joint(xml_element, joint)
 
         return xml_element
+
+    def __eq__(self, other):
+        if not isinstance(other, URDF):
+            raise NotImplemented
+        return self.robot == other.robot

tests/test_urdf.py

@@ -31,3 +31,26 @@ def test_validate():
 def test_mimic_joint():
     urdf_fname = os.path.join(DIR_MODELS, "franka", "franka.urdf")
     urdf_model = urdf.URDF.load(urdf_fname)
+
+    assert True
+
+
+def test_equality():
+    urdf_fname = os.path.join(DIR_MODELS, "franka", "franka.urdf")
+    urdf_model_0 = urdf.URDF.load(urdf_fname)
+
+    urdf_model_1 = urdf.URDF.load(urdf_fname)
+
+    assert urdf_model_0 == urdf_model_1
+
+
+def test_equality_different_link_order():
+    robot_0 = _create_robot()
+    robot_0.links.append(urdf.Link(name="link_0"))
+    robot_0.links.append(urdf.Link(name="link_1"))
+
+    robot_1 = _create_robot()
+    robot_1.links.append(urdf.Link(name="link_1"))
+    robot_1.links.append(urdf.Link(name="link_0"))
+
+    assert robot_0 == robot_1