Implement Fluid Generation

src/boat_simulator/boat_simulator/nodes/physics_engine/fluid_generation.py

@@ -5,31 +5,31 @@
 
 from boat_simulator.common.generators import VectorGenerator
 from boat_simulator.common.types import Scalar
+from boat_simulator.common.utils import bound_to_180, rad_to_degrees
 
 
 class FluidGenerator:
  """This class provides functionality to generate velocity vectors representing fluid movements.
 
  Attributes:
- `generator` (VectorGenerator): The vector generator used to generate fluid velocities.
+ `generator` (VectorGenerator): The vector generator used to generate 2D fluid velocities.
  `velocity` (NDArray): The most recently generated fluid velocity vector, expressed in
- meters per second (m/s).
+ meters per second (m/s). It is expected to be a 2D vector.
  """
 
  def __init__(self, generator: VectorGenerator):
  self.__generator = generator
  self.__velocity = np.array(self.__generator.next())
+ assert self.__velocity.shape == (2,)
 
  def next(self) -> NDArray:
  """Generates the next velocity vector for the fluid simulation.
 
  Returns:
  NDArray: An array representing the updated velocity vector for the fluid simulation.
  """
-
- # TODO: Implement this to generate the next velocity vector.
-
- raise NotImplementedError()
+ self.__velocity = np.array(self.__generator.next())
+ return self.__velocity
 
  @property
  def velocity(self) -> NDArray:
@@ -39,8 +39,7 @@ def velocity(self) -> NDArray:
  NDArray: The velocity vector of the fluid, expressed in meters per second (m/s) and
  ranging from negative infinity to positive infinity.
  """
-
- raise NotImplementedError()
+ return self.__velocity
 
  @property
  def speed(self) -> Scalar:
@@ -50,10 +49,7 @@ def speed(self) -> Scalar:
  Scalar: The speed of the fluid, expressed in meters per second (m/s) and within the
  range of 0 to positive infinity.
  """
-
- # TODO: Implement this using the current velocity vector.
-
- raise NotImplementedError()
+ return np.linalg.norm(self.__velocity)
 
  @property
  def direction(self) -> Scalar:
@@ -63,7 +59,6 @@ def direction(self) -> Scalar:
  Scalar: The direction of the fluid, expressed in degrees and bounded between
  [-180, 180).
  """
-
- # TODO: Implement this using the current velocity vector.
-
- raise NotImplementedError()
+ angle_rad = np.arctan2(self.__velocity[1], self.__velocity[0])
+ angle_deg = rad_to_degrees(angle_rad)
+ return bound_to_180(angle_deg)

src/boat_simulator/tests/unit/nodes/physics_engine/test_fluids.py

@@ -1,9 +1,75 @@
 """Tests classes and functions in boat_simulator/nodes/physics_engine/fluids.py"""
 
+import numpy as np
+import pytest
+
+from boat_simulator.common.generators import ConstantGenerator, MVGaussianGenerator
+from boat_simulator.nodes.physics_engine.fluid_generation import FluidGenerator
+
 
 class TestFluidGenerator:
- pass
+ @pytest.mark.parametrize(
+ "vector",
+ [
+ (np.array([1, 0])),
+ (np.array([0, 1])),
+ (np.array([1, 0])),
+ ],
+ )
+ def test_velocity_constant(self, vector):
+ vector_generator = ConstantGenerator(constant=vector)
+ fluid_generator = FluidGenerator(generator=vector_generator)
+ first_fluid_vector = fluid_generator.velocity
+ assert np.all(first_fluid_vector == vector)
+ assert np.all(first_fluid_vector == fluid_generator.next())
+
+ @pytest.mark.parametrize(
+ "mean, cov",
+ [
+ (np.array([1, 2]), np.array([[2, 1], [1, 2]])),
+ (np.array([4, 5]), np.array([[3, 1], [1, 3]])),
+ (np.array([100, 50]), np.array([[10, 5], [5, 10]])),
+ (np.array([120, 130]), np.array([[10, 5], [5, 10]])),
+ ],
+ )
+ def test_velocity_random(self, mean, cov):
+ vector_generator = MVGaussianGenerator(mean=mean, cov=cov)
+ fluid_generator = FluidGenerator(vector_generator)
+ first_fluid_vector = fluid_generator.velocity
+ next_fluid_vector = fluid_generator.next()
+ assert np.all(next_fluid_vector != first_fluid_vector)
 
+ @pytest.mark.parametrize(
+ "vector",
+ [
+ (np.array([1, 0])),
+ (np.array([0, 1])),
+ (np.array([-1, 0])),
+ (np.array([0, -1])),
+ (np.array([1, 1])),
+ (np.array([-1, -1])),
+ ],
+ )
+ def test_speed(self, vector):
+ vector_generator = ConstantGenerator(constant=vector)
+ fluid_generator = FluidGenerator(generator=vector_generator)
+ generated_fluid_vector = fluid_generator.next()
+ assert np.all(vector == generated_fluid_vector)
+ assert np.linalg.norm(vector) == fluid_generator.speed
 
-class TestWindGenerator:
- pass
+ @pytest.mark.parametrize(
+ "vector, expected_direction",
+ [
+ (np.array([1, 0]), 0),
+ (np.array([0, 1]), 90),
+ (np.array([-1, 0]), -180),
+ (np.array([0, -1]), -90),
+ (np.array([1, 1]), 45),
+ (np.array([-1, -1]), -135),
+ ],
+ )
+ def test_direction(self, vector, expected_direction):
+ vector_generator = ConstantGenerator(constant=vector)
+ fluid_generator = FluidGenerator(generator=vector_generator)
+ calculated_direction = fluid_generator.direction
+ assert np.isclose(calculated_direction, expected_direction, atol=1e-7)