'''
Sampling functions for generating random points on geometric objects.
'''
import random
import math
import numpy as np
from typing import List, Tuple, Optional, FrozenSet, Union
import open3d as o3d
def __set_random_seed(seed):
"""
Set the random seed for reproducibility.
:param seed: int
The seed value for the random number generator.
"""
random.seed(seed)
def __sample_point_circle_2d(center: Tuple[float, float], radius: float=1) -> Tuple[float, float]:
"""
Generate a random point on a 2D circle with a specified radius and center, using rejection sampling.
:param center: tuple
A tuple (x, y) representing the center of the circle.
:param radius: float, optional
The radius of the circle. Default is 1.
:return: tuple
A tuple (x, y) representing the coordinates of the sampled point.
"""
if radius <= 0:
raise ValueError("Radius must be positive.")
while True:
# Generate a random point on the circle with radius 1 centered at (0,0)
x = random.uniform(-1, 1)
y = random.uniform(-1, 1)
# Scale the coordinates to the desired radius
x *= radius
y *= radius
# Translate the point to the desired center
x += center[0]
y += center[1]
# Check if the point is within the circle
if (x - center[0])**2 + (y - center[1])**2 <= radius**2:
return x, y
[docs]def sampling_circle_2d(n_samples:int=1, center:Tuple[float, float]=(0,0), radius:float=1, seed:Optional[int]=None):
"""
Generate random samples on a 2D circle with a specified radius and center.
:param n_samples: The number of random samples to generate on the circle.
:type n_samples: int
:param center: A tuple (x, y) representing the center of the circle. Default is (0,0).
:type center: Tuple[float, float]
:param radius: The radius of the circle. Default is 1.
:type radius: float
:param seed: The seed value for the random number generator. Default is None.
:type seed: int
:return: A list of tuples (x, y) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float]]
.. note:: The samples are uniformly distributed on the circle.
Examples
--------
Generate 100 random samples on a circle with center (2,3) and radius 5:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
Define the limits of the parallelogram and the number of points to sample:
>>> n_samples = 100
>>> center = (2,3)
>>> radius = 5
Generate the samples:
>>> samples = sampling.sampling_circle_2d(n_samples=100, center=center, radius=radius, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[(3.3942679845788373, -1.7498924477733304),
(-0.24970681630880742, 0.23210738148822774),
(4.364712141640124, 4.766994874229113),
(1.2192181968527043, -1.7020278056192968),
(-0.8136202519639664, 3.0535528810336237)]
Plot the samples:
>>> fig, ax = plt.subplots()
>>> xlim_min = center[0] - radius
>>> xlim_max = center[0] + radius
>>> ylim_min = center[1] - radius
>>> ylim_max = center[1] + radius
>>> graph_limits = geometry.get_limits_of_graph_from_limits_of_object(xlim_min, xlim_max, ylim_min, ylim_max)
>>> ax.set_xlim(graph_limits[0], graph_limits[1]) # Set x-axis limits
>>> ax.set_ylim(graph_limits[2], graph_limits[3]*1.1) # Set y-axis limits
>>> ax.scatter(*zip(*samples))
>>> ax.set_aspect('equal')
>>> # create title from n_samples, center, and radius, using f-string
>>> title = (f'{n_samples} Samples on a Circle with Center {center} and Radius {radius}')
>>> ax.set_title(title)
>>> # draw also the circle in red
>>> circle = plt.Circle(center, radius, color='r', fill=False)
>>> ax.add_artist(circle)
>>> # draw the X and Y axes in dotted lines
>>> ax.axhline(0, linestyle='dotted', color='black')
>>> ax.axvline(0, linestyle='dotted', color='black')
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> plt.show()
|sampling_circle_2d|
.. |sampling_circle_2d| image:: ../../doc/source/_static/images/sampling_circle_2d.png
"""
# Set the random seed for reproducibility if provided
if seed is not None:
__set_random_seed(seed)
# Generate the specified number of samples on the circle
samples = [__sample_point_circle_2d(center, radius) for _ in range(n_samples)]
return samples
def __sample_point_circle_3d(radius: float = 1.0, center: np.ndarray =np.array([0, 0, 0]), normal: np.ndarray=np.array([0, 0, 1])) -> np.ndarray:
'''
Sample a point from a 3D circle using the rejection sampling method.
:param radius: The radius of the circle.
:type radius: float
:param center: The center of the circle.
:type center: np.ndarray
:param normal: The normal vector of the plane on which the circle lies.
:type normal: np.ndarray
:return: A list of tuples (x, y, z) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float, float]]
.. note:: The samples are uniformly distributed on the circle.
'''
normal = normal / np.linalg.norm(normal)
while True:
# Generate a random point within the bounding box
point = center + np.array([random.uniform(-radius, radius) for _ in range(3)])
# Project the point onto the plane defined by the circle
projected_point = point - np.dot(point - center, normal) * normal
# Check if the projected point lies within the circle
if np.linalg.norm(projected_point - center) <= radius:
return projected_point
[docs]def sampling_circle_3d(n_samples, radius: float = 1.0, center: np.ndarray =np.array([0, 0, 0]),
normal: np.ndarray=np.array([0, 0, 1]), seed: Optional[int]=None) -> List[np.ndarray]:
'''
Sample a n_samples number of points from a 3D circle using the rejection sampling method.
:param n_samples: The number of samples to generate.
:type n_samples: int
:param radius: The radius of the circle.
:type radius: float
:param center: The center of the circle.
:type center: np.ndarray
:param normal: The normal vector of the plane on which the circle lies.
:type normal: np.ndarray
:return: A list of tuples (x, y, z) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float, float]]
.. note:: The samples are uniformly distributed on the circle.
:Example:
::
Sample 100 points from a circle in an arbitrary position and with arbitrary normal vector:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geom
>>> import rsaitehu.matplot3d as plt3d
>>> import matplotlib.pyplot as plt
>>> import numpy as np
Define the parameters of the circle and the number of points to sample:
>>> n_samples = 100
>>> radius = 5
>>> center = np.array([1, 2, 0])
>>> normal = np.array([1, 1, 0]) / np.linalg.norm(np.array([1, 1, 0]))
Sample the points:
>>> samples = sampling.sampling_circle_3d(n_samples=n_samples, radius=radius, center=center, normal=normal, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[array([ 4.07208022, -1.07208022, -2.24970682]),
array([-1.56630238, 4.56630238, 1.76699487]),
array([0.05579622, 2.94420378, 0.05355288]),
array([0.13849159, 2.86150841, 1.49884438]),
array([2.62250429, 0.37749571, 0.89265684])]
Plot the 3D circle and the samples:
>>> fig = plt.figure()
>>> ax = fig.add_subplot(111, projection='3d')
>>> plt3d.draw_circumference(center=center, radius=radius, normal=normal, color="blue", alpha=0.2, ax=ax)
>>> xlim_min = np.min([sample[0] for sample in samples])
>>> xlim_max = np.max([sample[0] for sample in samples])
>>> ylim_min = np.min([sample[1] for sample in samples])
>>> ylim_max = np.max([sample[1] for sample in samples])
>>> zlim_min = np.min([sample[2] for sample in samples])
>>> zlim_max = np.max([sample[2] for sample in samples])
>>> graph_limits = geom.get_limits_of_3d_graph_from_limits_of_object(xlim_min, xlim_max, ylim_min, ylim_max, zlim_min, zlim_max)
>>> ax.set_xlim(graph_limits[0], graph_limits[1]) # Set x-axis limits
>>> ax.set_ylim(graph_limits[2], graph_limits[3]) # Set y-axis limits
>>> ax.set_zlim(graph_limits[4], graph_limits[5]) # Set z-axis limits
>>> ax.scatter(*zip(*samples))
>>> # create title from n_samples, center, and radius, using f-string
>>> title = (f'{n_samples} Samples on a Circle with Center {center} and Radius {radius}')
>>> ax.set_title(title)
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> ax.set_zlabel('Z')
>>> plt.show()
|sampling_circle_3d|
.. |sampling_circle_3d| image:: ../../doc/source/_static/images/sampling_circle_3d.png
'''
if seed is not None:
random.seed(seed)
samples = [__sample_point_circle_3d(radius, center, normal) for _ in range(n_samples)]
return samples
def __sample_point_parallelogram_2d(normal1: Tuple[float, float], normal2: Tuple[float, float], center: Tuple[float, float], length1: float, length2: float) -> Tuple[float, float]:
'''
Sample a point from a parallelogram with sides parallel to the vectors normal1 and normal2.
:param normal1: Tuple[float, float]
The first vector normal to the sides of the parallelogram.
:param normal2: Tuple[float, float]
The second vector normal to the sides of the parallelogram.
:param center: Tuple[float, float]
The center of the parallelogram.
:param length1: float
The length of the first side of the parallelogram.
:param length2: float
The length of the second side of the parallelogram.
:return: Tuple[float, float]
A tuple (x, y) representing the coordinates of the sampled point.
'''
# Generate two random numbers between -length1/2 and length1/2 and -length2/2 and length2/2 respectively
x = random.uniform(-length1/2, length1/2)
y = random.uniform(-length2/2, length2/2)
# Those numbers represent the coordinates of the sampled point in the normal coordinate system
# Transform the coordinates to the global coordinate system
projected_point = (x * normal1[0] + y * normal2[0] + center[0], x * normal1[1] + y * normal2[1] + center[1])
return projected_point
[docs]def sampling_parallelogram_2d(n_samples: int, normal1: Tuple[float, float], normal2: Tuple[float, float],
center: Tuple[float, float], length1: float, length2: float,
seed: Optional[int] = None) -> List[Tuple[float, float]]:
"""
Sample a n_samples number of points from a 2D parallelogram.
The parallelogram has sides parallel to the vectors normal1 and normal2,
with lengths length1 and length2 respectively, and centered at center.
:param n_samples: The number of samples to generate.
:type n_samples: int
:param normal1: The first vector normal to the sides of the parallelogram.
:type normal1: Tuple[float, float]
:param normal2: The second vector normal to the sides of the parallelogram.
:type normal2: Tuple[float, float]
:param center: The center of the parallelogram.
:type center: Tuple[float, float]
:param length1: The length of the first side of the parallelogram.
:type length1: float
:param length2: The length of the second side of the parallelogram.
:type length2: float
:return: A list of tuples (x, y) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float]]
.. note:: The samples are uniformly distributed on the parallelogram.
Examples
--------
Sample 100 points from a parallelogram in an arbitrary position and with arbitrary sides:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
>>> import numpy as np
Define the parameters of the parallelogram and the number of points to sample:
>>> n_samples = 100
>>> normal1 = (1, 1)
>>> normal2 = (-2, 1)
>>> center = (1, 2)
>>> length1 = 5
>>> length2 = 4
Sample the points:
>>> samples = sampling.sampling_parallelogram_2d(n_samples=n_samples, normal1=normal1, normal2=normal2,
center=center, length1=length1, length2=length2, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[(5.497047950508083, 0.7971770131800864),
(2.0894606866550145, -0.23201045555911293),
(0.7687601714367718, 3.8891540205117074),
(6.265387177488898, 2.3086531690418917),
(4.3712313429217895, -0.2712020238213664)]
Plot the samples:
>>> fig, ax = plt.subplots()
>>> ax.scatter(*zip(*samples))
>>> ax.set_aspect('equal')
>>> center = np.array(center)
>>> normal1 = np.array(normal1)
>>> normal2 = np.array(normal2)
>>> vertex1 = center + normal1 * length1 / 2 + normal2 * length2 / 2
>>> vertex2 = center - normal1 * length1 / 2 + normal2 * length2 / 2
>>> vertex3 = center - normal1 * length1 / 2 - normal2 * length2 / 2
>>> vertex4 = center + normal1 * length1 / 2 - normal2 * length2 / 2
>>> xlim_min = min(vertex1[0], vertex2[0], vertex3[0], vertex4[0])
>>> xlim_max = max(vertex1[0], vertex2[0], vertex3[0], vertex4[0])
>>> ylim_min = min(vertex1[1], vertex2[1], vertex3[1], vertex4[1])
>>> ylim_max = max(vertex1[1], vertex2[1], vertex3[1], vertex4[1])
>>> graph_limits = geometry.get_limits_of_graph_from_limits_of_object(xlim_min, xlim_max, ylim_min, ylim_max)
>>> ax.set_xlim(graph_limits[0], graph_limits[1]) # Set x-axis limits
>>> ax.set_ylim(graph_limits[2], graph_limits[3]) # Set y-axis limits
>>> # create title from n_samples, center, and radius, using f-string
>>> title = (f'{n_samples} Samples on a Parallelogram with normal vectors ({normal1[0]}, {normal1[1]}) '
>>> f'and ({normal2[0]}, {normal2[1]}), center ({center[0]}, {center[1]}), length1 of {length1}, '
>>> f'and length2 of {length2}'
>>> )
>>> ax.set_title(title)
>>> # draw also the parallelogram in red
>>> vertices = geometry.get_parallelogram_2d_vertices(center, normal1, normal2, length1, length2)
>>> ax.plot([vertices[0][0], vertices[1][0]], [vertices[0][1], vertices[1][1]], color='r')
>>> ax.plot([vertices[1][0], vertices[2][0]], [vertices[1][1], vertices[2][1]], color='r')
>>> ax.plot([vertices[2][0], vertices[3][0]], [vertices[2][1], vertices[3][1]], color='r')
>>> ax.plot([vertices[3][0], vertices[0][0]], [vertices[3][1], vertices[0][1]], color='r')
>>> # Draw the X and Y axes in dotted lines
>>> ax.axhline(0, linestyle='dotted', color='black')
>>> ax.axvline(0, linestyle='dotted', color='black')
>>> # Draw the normals at a quarter of their corresponding length
>>> quarter_length1 = length1 / 8
>>> quarter_length2 = length2 / 8
>>> arrow_length1 = quarter_length1 / 2
>>> arrow_length2 = quarter_length2 / 2
>>> ax.arrow(center[0], center[1], normal1[0] * quarter_length1, normal1[1] * quarter_length1,
>>> head_width=arrow_length1, head_length=arrow_length2, fc='b', ec='b')
>>> ax.arrow(center[0], center[1], normal2[0] * quarter_length2, normal2[1] * quarter_length2,
>>> head_width=arrow_length2, head_length=arrow_length1, fc='b', ec='b')
>>> plt.show()
|sampling_parallelogram_2d|
.. |sampling_parallelogram_2d| image:: ../../doc/source/_static/images/sampling_parallelogram_2d.png
"""
if seed is not None:
random.seed(seed)
normal1 = np.array(normal1)
normal2 = np.array(normal2)
center = np.array(center)
samples = [__sample_point_parallelogram_2d(normal1, normal2, center, length1, length2) for _ in range(n_samples)]
return samples
def __sample_point_alligned_parallelogram_2d(min_x: float, max_x: float, min_y: float, max_y: float) -> Tuple[float, float]:
'''
Sample a point from a parallelogram with sides parallel to the x and y axes.
:param min_x: float
The minimum x coordinate of the parallelogram.
:param max_x: float
The maximum x coordinate of the parallelogram.
:param min_y: float
The minimum y coordinate of the parallelogram.
:param max_y: float
The maximum y coordinate of the parallelogram.
:return: Tuple[float, float]
A tuple (x, y) representing the coordinates of the sampled point.
.. note:: The samples are uniformly distributed on the parallelogram.
Examples
--------
Sample a point from a parallelogram with sides parallel to the x and y axes:
>>> sample_point_alligned_parallelogram(-1, 1, -1, 1)
(-0.5, 0.5)
'''
x = random.uniform(min_x, max_x)
y = random.uniform(min_y, max_y)
return x, y
[docs]def sampling_alligned_parallelogram_2d(n_samples: int, min_x: float, max_x: float, min_y: float, max_y: float,
seed: Optional[int] = None) -> List[Tuple[float, float]]:
'''
Sample points from a parallelogram with sides parallel to the x and y axes.
:param n_samples: The number of samples to generate.
:type n_samples: int
:param min_x: The minimum x coordinate of the parallelogram.
:type min_x: float
:param max_x: The maximum x coordinate of the parallelogram.
:type max_x: float
:param min_y: The minimum y coordinate of the parallelogram.
:type min_y: float
:param max_y: The maximum y coordinate of the parallelogram.
:type max_y: float
:param seed: The seed to use for the random number generator.
:type seed: Optional[int]
:return: A list of tuples (x, y) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float]]
.. note:: The samples are uniformly distributed on the parallelogram.
Examples
--------
Sample 100 points from a parallelogram with sides parallel to the x and y axes:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
Define the limits of the parallelogram and the number of points to sample:
>>> n_samples = 100
>>> min_x = -3
>>> max_x = 2
>>> min_y = -1
>>> max_y = 5
Sample the points:
>>> samples = sampling.sampling_alligned_parallelogram_2d(n_samples=n_samples, min_x=min_x,
>>> max_x=max_x, min_y=min_y, max_y=max_y, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[(0.19713399228941864, -0.8499354686639984),
(-1.6248534081544037, 0.3392644288929365),
(0.6823560708200622, 3.0601969245374683),
(1.460897838524227, -0.4783670042235031),
(-0.8903909015736478, -0.8212166833715779)]
Plot the samples:
>>> fig, ax = plt.subplots()
>>> graph_limits = geometry.get_limits_of_graph_from_limits_of_object(min_x, max_x, min_y, max_y)
>>> ax.set_xlim(graph_limits[0], graph_limits[1]) # Set x-axis limits
>>> ax.set_ylim(graph_limits[2], graph_limits[3]*1.1) # Set y-axis limits
>>> ax.scatter(*zip(*samples))
>>> ax.set_aspect('equal')
>>> # create title from n_samples, center, and radius, usign fstring
>>> title = (f'{n_samples} Samples on an axes alligned Parallelogram with bottom left corner '
>>> f'({min_x}, {min_y}) and top right corner ({max_x}, {max_y})'
>>> )
>>> ax.set_title(title)
>>> # draw also the parallelogram in red
>>> ax.plot([min_x, max_x], [min_y, min_y], color='r')
>>> ax.plot([min_x, max_x], [max_y, max_y], color='r')
>>> ax.plot([min_x, min_x], [min_y, max_y], color='r')
>>> ax.plot([max_x, max_x], [min_y, max_y], color='r')
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> # Draw the X and Y axes in dotted lines
>>> ax.axhline(0, linestyle='dotted', color='black')
>>> ax.axvline(0, linestyle='dotted', color='black')
>>> plt.show()
|sampling_alligned_parallelogram_2d|
.. |sampling_alligned_parallelogram_2d| image:: ../../doc/source/_static/images/sampling_alligned_parallelogram_2d.png
'''
if seed is not None:
random.seed(seed)
samples = [__sample_point_alligned_parallelogram_2d(min_x, max_x, min_y, max_y) for _ in range(n_samples)]
return samples
def __sample_point_parallelogram_3d(normal1: Tuple[float, float, float], normal2: Tuple[float, float, float],
center: Tuple[float, float, float], length1: float, length2: float) -> Tuple[float, float, float]:
'''
Sample a point from a parallelogram with sides parallel to the vectors normal1 and normal2.
:param normal1: Tuple[float, float, float]
The first vector normal to the sides of the parallelogram.
:param normal2: Tuple[float, float, float]
The second vector normal to the sides of the parallelogram.
:param center: Tuple[float, float, float]
The center of the parallelogram.
:param length1: float
The length of the first side of the parallelogram.
:param length2: float
The length of the second side of the parallelogram.
:return: Tuple[float, float, float]
A tuple (x, y, z) representing the coordinates of the sampled point.
'''
# Generate two random numbers between -length1/2 and length1/2 and -length2/2 and length2/2 respectively
x = random.uniform(-length1/2, length1/2)
y = random.uniform(-length2/2, length2/2)
# Those numbers represent the coordinates of the sampled point in the normal coordinate system
# Transform the coordinates to the global coordinate system
projected_point = x * np.array(normal1) + y * np.array(normal2) + np.array(center)
return projected_point
def __sample_point_parallelepiped_3d(normal1: Tuple[float, float, float], normal2: Tuple[float, float, float],
normal3: Tuple[float, float, float], center: Tuple[float, float, float],
length1: float, length2: float, length3: float) -> Tuple[float, float, float]:
'''
Sample a point from a parallelepiped with sides parallel to the vectors normal1, normal2 and normal3.
:param normal1: Tuple[float, float, float]
The first vector normal to the sides of the parallelepiped.
:param normal2: Tuple[float, float, float]
The second vector normal to the sides of the parallelepiped.
:param normal3: Tuple[float, float, float]
The third vector normal to the sides of the parallelepiped.
:param center: Tuple[float, float, float]
The center of the parallelepiped.
:param length1: float
The length of the first side of the parallelepiped.
:param length2: float
The length of the second side of the parallelepiped.
:param length3: float
The length of the third side of the parallelepiped.
:return: Tuple[float, float, float]
A tuple (x, y, z) representing the coordinates of the sampled point.
'''
# Generate two random numbers between -length1/2 and length1/2 and -length2/2 and length2/2 respectively
x = random.uniform(-length1/2, length1/2)
y = random.uniform(-length2/2, length2/2)
z = random.uniform(-length3/2, length3/2)
# Those numbers represent the coordinates of the sampled point in the normal coordinate system
# Transform the coordinates to the global coordinate system
projected_point = x * np.array(normal1) + y * np.array(normal2) + z * np.array(normal3) + np.array(center)
return projected_point
[docs]def sampling_parallelogram_3d(n_samples: int, normal1: Tuple[float, float, float], normal2: Tuple[float, float, float],
center: Tuple[float, float, float], length1: float, length2: float, seed: Optional[int] = None) -> List[Tuple[float, float, float]]:
'''
Sample n_samples points from a parallelogram
The parallelogram is defined by the vectors normal1 and normal2, the center and the lengths of the sides.
:param n_samples: The number of samples to generate.
:type n_samples: int
:param normal1: The first vector normal to the sides of the parallelepiped.
:type normal1: Tuple[float, float, float]
:param normal2: The second vector normal to the sides of the parallelepiped.
:type normal2: Tuple[float, float, float]
:param center: The center of the parallelepiped.
:type center: Tuple[float, float, float]
:param length1: The length of the first side of the parallelepiped.
:type length1: float
:param length2: The length of the second side of the parallelepiped.
:type length2: float
:param seed: The seed to use for the random number generator.
:type seed: Optional[int]
:return: A list of tuples (x, y, z) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float, float]]
.. note:: The samples are uniformly distributed on the parallelogram.
Examples
--------
Sample 100 points from a parallelogram in an arbitrary position and with arbitrary sides:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
>>> import numpy as np
Define the parameters of the parallelogram and the number of points to sample:
>>> n_samples = 100
>>> normal1 = (1, 1, 0)
>>> normal2 = (-2, 1, 1)
>>> center = (1, 2, 0)
>>> length1 = 5
>>> length2 = 4
Sample the points:
>>> samples = sampling.sampling_parallelogram_3d(n_samples=n_samples, normal1=normal1, normal2=normal2,
... center=center, length1=length1, length2=length2, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[array([ 5.49704795, 0.79717701, -1.89995698]),
array([ 2.08946069, -0.23201046, -1.10715705]),
array([0.76876017, 3.88915402, 0.70679795]),
array([ 6.26538718, 2.30865317, -1.65224467]),
array([ 4.37123134, -0.27120202, -1.88081112])]
Plot the 3D parallelogram and the samples:
>>> samples = np.array(samples)
>>> fig = plt.figure()
>>> ax = fig.add_subplot(111, projection='3d')
>>> ax.scatter(samples[:, 0], samples[:, 1], samples[:, 2])
>>> # create title from n_samples, center, and radius, using fstring
>>> title = (f'{n_samples} Samples on a 3D Parallelogram with normal vectors {normal1} and {normal2}, '
>>> f'center {center}, length1 of {length1} and length2 of {length2}')
>>> ax.set_title(title)
>>> # Draw the parallelogram
>>> vertices = geometry.get_parallelogram_3d_vertices(center, normal1, normal2, length1, length2)
>>> # Define the edges of the 3d parallelogram
>>> edges = [(0, 1), (1, 2), (2, 3), (3, 0)]
>>> # Plot the edges
>>> for edge in edges:
>>> ax.plot([vertices[edge[0]][0], vertices[edge[1]][0]],
>>> [vertices[edge[0]][1], vertices[edge[1]][1]],
>>> [vertices[edge[0]][2], vertices[edge[1]][2]], color='red')
>>> # Draw the normals at a quarter of their corresponding length
>>> quarter_length1 = length1 / 4
>>> quarter_length2 = length2 / 4
>>> arrow_length1 = quarter_length1 / 2
>>> arrow_length2 = quarter_length2 / 2
>>> ax.quiver(center[0], center[1], center[2], normal1[0], normal1[1], normal1[2], length=arrow_length1, normalize=False, color='red')
>>> ax.quiver(center[0], center[1], center[2], normal2[0], normal2[1], normal2[2], length=arrow_length2, normalize=False, color='red')
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> ax.set_zlabel('Z')
>>> plt.show()
|sampling_parallelogram_3d|
.. |sampling_parallelogram_3d| image:: ../../doc/source/_static/images/sampling_parallelogram_3d.png
'''
if seed is not None:
random.seed(seed)
normal1 = np.array(normal1)
normal2 = np.array(normal2)
center = np.array(center)
samples = [__sample_point_parallelogram_3d(normal1, normal2, center, length1, length2) for _ in range(n_samples)]
return samples
[docs]def sampling_parallelepiped_3d(n_samples: int, normal1: Tuple[float, float, float], normal2: Tuple[float, float, float],
normal3: Tuple[float, float, float], center: Tuple[float, float, float],
length1: float, length2: float, length3: float, seed: Optional[int] = None) -> List[Tuple[float, float, float]]:
'''
Sample n_samples points from a parallelepiped
The parallelogram is defined by the vectors normal1, normal2 and normal3, the center and the lengths of the sides.
:param n_samples: The number of samples to generate.
:type n_samples: int
:param normal1: The first vector normal to the sides of the parallelepiped.
:type normal1: Tuple[float, float, float]
:param normal2: The second vector normal to the sides of the parallelepiped.
:type normal2: Tuple[float, float, float]
:param normal3: The third vector normal to the sides of the parallelepiped.
:type normal3: Tuple[float, float, float]
:param center: The center of the parallelepiped.
:type center: Tuple[float, float, float]
:param length1: The length of the first side of the parallelepiped.
:type length1: float
:param length2: The length of the second side of the parallelepiped.
:type length2: float
:param length3: The length of the third side of the parallelepiped.
:type length3: float
:param seed: The seed to use for the random number generator.
:type seed: Optional[int]
:return: A list of tuples (x, y, z) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float, float]]
.. note:: The samples are uniformly distributed on the parallelepiped.
Examples
--------
Sample 100 points from a parallelepiped in an arbitrary position and with arbitrary sides:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
>>> import numpy as np
Define the parameters of the parallelepiped and the number of points to sample:
>>> n_samples = 100
>>> normal1 = (1, 1, 0)
>>> normal2 = (-2, 1, 1)
>>> normal3 = (1, -1, 3)
>>> center = (1, 2, 0)
>>> length1 = 5
>>> length2 = 4
>>> length3 = 3
Sample the points:
>>> samples = sampling.sampling_parallelepiped_3d(n_samples=n_samples, normal1=normal1, normal2=normal2,
... normal3=normal3, center=center, length1=length1,
... length2=length2, length3=length3, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[array([ 4.82213591, 1.47208906, -3.92469311]),
array([-1.74561756, 1.03184009, 2.53618024]),
array([ 6.03115264, 2.54288771, -2.35494829]),
array([ 0.91594816, -1.49252787, -1.07725051]),
array([ 1.49163196, -2.02162286, 0.14431054])]
Plot the 3D parallelepiped and the samples:
>>> samples = np.array(samples)
>>> fig = plt.figure()
>>> ax = fig.add_subplot(111, projection='3d')
>>> ax.scatter(samples[:, 0], samples[:, 1], samples[:, 2])
>>> # create title from n_samples, center, and radius, using fstring
>>> title = (f'{n_samples} Samples on a 3D Parallelepiped with normal vectors {normal1}, {normal2} and {normal3}, '
>>> f'center {center}, length1 of {length1}, length2 of {length2} and length3 of {length3}')
>>> ax.set_title(title)
>>> # Draw the parallelepiped
>>> vertices = geometry.get_parallelepiped_3d_vertices(center, normal1, normal2, normal3, length1, length2, length3)
>>> # Define the edges of the 3d parallelepiped
>>> edges = [(0, 1), (1, 2), (2, 3), (3, 0), (4, 5), (5, 6),
>>> (6, 7), (7, 4), (0, 4), (1, 5), (2, 6), (3, 7)]
>>> # Plot the edges
>>> for edge in edges:
>>> ax.plot([vertices[edge[0]][0], vertices[edge[1]][0]],
>>> [vertices[edge[0]][1], vertices[edge[1]][1]],
>>> [vertices[edge[0]][2], vertices[edge[1]][2]], color='red')
>>> # Draw the normals at a quarter of their corresponding length
>>> quarter_length1 = length1 / 4
>>> quarter_length2 = length2 / 4
>>> arrow_length1 = quarter_length1 / 2
>>> arrow_length2 = quarter_length2 / 2
>>> ax.quiver(center[0], center[1], center[2], normal1[0], normal1[1], normal1[2], length=arrow_length1, normalize=False, color='red')
>>> ax.quiver(center[0], center[1], center[2], normal2[0], normal2[1], normal2[2], length=arrow_length2, normalize=False, color='red')
>>> ax.quiver(center[0], center[1], center[2], normal3[0], normal3[1], normal3[2], length=arrow_length2, normalize=False, color='red')
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> ax.set_zlabel('Z')
>>> plt.show()
|sampling_parallelepiped_3d|
.. |sampling_parallelepiped_3d| image:: ../../doc/source/_static/images/sampling_parallelepiped_3d.png
'''
if seed is not None:
random.seed(seed)
normal1 = np.array(normal1)
normal2 = np.array(normal2)
normal3 = np.array(normal3)
center = np.array(center)
samples = [__sample_point_parallelepiped_3d(normal1, normal2, normal3, center, length1, length2, length3) for _ in range(n_samples)]
return samples
def __sample_point_cuboid(a, b, c, d, h):
u = random.random()
v = random.random()
w = random.random()
x = a[0] + u * (b[0] - a[0]) + v * (c[0] - a[0]) + w * (d[0] - a[0])
y = a[1] + u * (b[1] - a[1]) + v * (c[1] - a[1]) + w * (d[1] - a[1])
z = a[2] + u * (b[2] - a[2]) + v * (c[2] - a[2]) + w * (d[2] - a[2]) + h
return x, y, z
def sampling_cuboid(n_samples, a, b, c, d, h):
samples = [__sample_point_cuboid(a, b, c, d, h) for _ in range(n_samples)]
return samples
def __sample_point_sphere(center:Tuple[float, float, float]=(0, 0, 0), radius:float=1):
"""
Generate a random point on a sphere with a specified radius and center, using rejection sampling.
:param center: tuple
A tuple (x, y, z) representing the center of the circle.
:param radius: float, optional
The radius of the circle. Default is 1.
:return: tuple
A tuple (x, y, z) representing the coordinates of the sampled point.
"""
while True:
# Generate a random point on the circle with radius 1 centered at (0,0)
x = random.uniform(-1, 1)
y = random.uniform(-1, 1)
z = random.uniform(-1, 1)
# Scale the coordinates to the desired radius
x *= radius
y *= radius
z *= radius
# Translate the point to the desired center
x += center[0]
y += center[1]
z += center[2]
# Check if the point is within the circle
if (x - center[0])**2 + (y - center[1])**2 + (z - center[2])**2 <= radius**2:
return x, y, z
[docs]def sampling_sphere(n_samples:int=1, center:Tuple[float, float, float]=(0,0,0), radius:float=1, seed:Optional[int]=None) \
-> List[Tuple[float, float, float]]:
"""
Generate random samples on a sphere with a specified radius and center.
:param n_samples: The number of random samples to generate on the circle.
:type n_samples: int
:param center: A tuple (x, y, z) representing the center of the circle. Default is (0,0).
:type center: Tuple[float, float, float]
:param radius: The radius of the circle. Default is 1.
:type radius: float
:param seed: The seed value for the random number generator. Default is None.
:type seed: Optional[int]
:return: A list of tuples (x, y, z) representing the coordinates of the sampled points.
:rtype: List[Tuple[float, float, float]]
.. note:: The samples are uniformly distributed on the sphere.
Examples
--------
Sample 100 points from a sphere:
Required imports:
>>> import rsaitehu.sampling as sampling
>>> import rsaitehu.geometry as geometry
>>> import matplotlib.pyplot as plt
>>> import numpy as np
Define the parameters of the sphere and the number of points to sample:
>>> n_samples = 100
>>> center = (2, 3, 1)
>>> radius = 5
Sample the points:
>>> samples = sampling.sampling_sphere(n_samples=n_samples, center=center, radius=radius, seed=42)
>>> # list the first 5 samples
>>> samples[:5]
[(-0.7678926185117723, 5.364712141640124, 2.766994874229113),
(2.4494148060321668, 0.204406220406967, 1.8926568387590872),
(3.9813939498822686, 1.4025051651799187, -2.4452050018821847),
(5.071282732743802, 5.297317866938179, 1.3622809145470074),
(6.731157639793706, 1.7853437720835348, 1.52040631273227)]
Plot the samples:
>>> samples = np.array(samples)
>>> fig = plt.figure()
>>> ax = fig.add_subplot(111, projection='3d')
>>> ax.scatter(samples[:, 0], samples[:, 1], samples[:, 2])
>>> # plot the sphere
>>> u, v = np.mgrid[0:2*np.pi:20j, 0:np.pi:10j]
>>> x = radius*np.cos(u)*np.sin(v) + center[0]
>>> y = radius*np.sin(u)*np.sin(v) + center[1]
>>> z = radius*np.cos(v) + center[2]
>>> ax.plot_wireframe(x, y, z, color="r")
>>> title = f'{n_samples} Samples on a Sphere with Center ({center[0]}, {center[1]}, {center[2]}) and Radius {radius}'
>>> ax.set_title(title)
>>> ax.set_xlabel('X')
>>> ax.set_ylabel('Y')
>>> ax.set_zlabel('Z')
>>> plt.show()
|sampling_sphere|
.. |sampling_sphere| image:: ../../doc/source/_static/images/sampling_sphere.png
"""
# Set the random seed for reproducibility if provided
if seed is not None:
__set_random_seed(seed)
# Generate the specified number of samples on the circle
samples = [__sample_point_sphere(center, radius) for _ in range(n_samples)]
return samples
[docs]def sampling_np_array_elements(elements:np.ndarray, num_samplings: int = 1, replacement: bool=False,
len_elements: Optional[int]=None, seed: Optional[int]=None) -> np.ndarray:
"""
Sample elements from a numpy array.
:param elements: The array of elements to sample from.
:type elements: np.ndarray
:param num_samplings: The number of elements to sample. Default is 1.
:type num_samplings: int
:param replacement: Whether to sample with replacement or not. Default is False.
:type replacement: bool
:param len_elements: The length of the elements array. Default is None.
:type len_elements: int
:param seed: The seed value for the random number generator. Default is None.
:type seed: int
:return: The sampled elements.
:rtype: np.ndarray
Examples
--------
>>> import numpy as np
>>> import rsaitehu.sampling as sampling
>>> sampling.sampling_np_array_elements(np.array([1,2,3,4,5]), 3, False, seed=42)
array([2, 5, 3])
>>> sampling.sampling_np_array_elements(np.array([(1,2),(3,4),(5,6),(7,8),(9,10)]), 3, False, seed=42)
array([[ 3, 4],
[ 9, 10],
[ 5, 6]])
"""
if len_elements is None:
len_elements = len(elements)
if seed is not None:
np.random.seed(seed)
random_elements_indices = np.random.choice(range(len_elements), num_samplings, replace=replacement)
random_elements = elements[random_elements_indices]
return random_elements
[docs]def sampling_pcd_points(pcd: o3d.geometry.PointCloud, num_points: int = 1, seed: Optional[int] = None):
"""
Sample points from a point cloud.
:param pcd: The point cloud to sample from.
:type pcd: o3d.geometry.PointCloud
:param num_points: The number of points to sample. Default is 1.
:type num_points: int
:param seed: The seed value for the random number generator. Default is None.
:type seed: int
:return: The sampled points.
:rtype: np.ndarray
Examples
--------
>>> import open3d as o3d
>>> import rsaitehu.sampling as sampling
>>> # Create a point cloud from random points sampled from a 3D parallelogram
>>> n_samples = 1000
>>> normal1 = (1, 1, 0)
>>> normal2 = (-2, 1, 1)
>>> normal3 = (1, -1, 3)
>>> center = (1, 2, 0)
>>> length1 = 5
>>> length2 = 4
>>> length3 = 3
>>> samples = sampling.sampling_parallelogram_3d(n_samples=n_samples, normal1=normal1, normal2=normal2,
normal3=normal3, center=center, length1=length1,
length2=length2, length3=length3, seed=42)
>>> samples[:5]
[array([ 4.82213591, 1.47208906, -3.92469311]),
array([-1.74561756, 1.03184009, 2.53618024]),
array([ 6.03115264, 2.54288771, -2.35494829]),
array([ 0.91594816, -1.49252787, -1.07725051]),
array([ 1.49163196, -2.02162286, 0.14431054])]
>>> pcd = o3d.geometry.PointCloud()
>>> pcd.points = o3d.utility.Vector3dVector(samples)
>>> # paint the point cloud in blue
>>> pcd.paint_uniform_color([0, 0, 1])
>>> # Sample 300 random points from the point cloud
>>> sampled_points = sampling.sampling_pcd_points(pcd, 300, seed=42)
>>> sampled_points[:5]
array([[-3.29369778, 2.38822478, 3.96820711],
[-0.15203634, 3.14597455, 3.11019749],
[ 2.41599518, -1.37126689, -3.70481201],
[ 3.02922805, -2.15456602, -0.98563083],
[ 0.75636732, 5.3772318 , -2.63251376]])
>>> # create a point cloud from the sampled points
>>> sampled_pcd = o3d.geometry.PointCloud()
>>> sampled_pcd.points = o3d.utility.Vector3dVector(sampled_points)
>>> # paint the sampled points in red
>>> sampled_pcd.paint_uniform_color([1, 0, 0])
>>> # visualize the point clouds
>>> o3d.visualization.draw_geometries([pcd, sampled_pcd])
|sampling_pcd_points|
.. |sampling_pcd_points| image:: ../../doc/source/_static/images/sampling_pcd_points.png
"""
points = np.asarray(pcd.points)
random_points = sampling_np_array_elements(elements=points, num_samplings=num_points, seed=seed)
return random_points
[docs]def sampling_np_arrays_from_enumerable(source_list: Union[List, np.ndarray], cardinality_of_np_arrays: int, number_of_np_arrays: int=1, num_source_elems: Optional[int] = None, seed: Optional[int] = None) -> List[np.ndarray]:
"""
Returns a list with **number_of_np_arrays** numpy arrays of size **cardinality_of_np_arrays** with random elements from a list or numpy array.
:param source_list: The list or numpy array to sample from.
:type source_list: Union[list, np.ndarray]
:param cardinality_of_np_arrays: The cardinality of the numpy arrays to generate.
:type cardinality_of_np_arrays: int
:param number_of_np_arrays: The number of numpy arrays to generate. Default is 1.
:type number_of_np_arrays: int
:param num_source_elems: The number of elements in the source list or numpy array. Default is None.
:type num_source_elems: int
:param seed: The seed value for the random number generator. Default is None.
:type seed: int
:return: List of numpy arrays containing the sampled arrays.
:rtype: List[np.ndarray]
:Example:
::
>>> import rsaitehu.sampling as sampling
>>> import numpy as np
>>> sampling.sampling_np_arrays_from_enumerable(np.array([1,2,3,4,5,6,7,8,9,10]), 3, 2, seed=42)
>>> [array([9, 2, 6]), array([1, 8, 3])]
>>> np.random.seed(42)
>>> random_3d_points = np.random.rand(100, 3)
>>> random_np_arrays_of_points = sampling.sampling_np_arrays_from_enumerable(random_3d_points, cardinality_of_np_arrays=3, number_of_np_arrays=4, seed=42)
>>> random_np_arrays_of_points
>>> [array([[0.85300946, 0.29444889, 0.38509773],
>>> [0.72821635, 0.36778313, 0.63230583],
>>> [0.54873379, 0.6918952 , 0.65196126]]),
>>> array([[0.32320293, 0.51879062, 0.70301896],
>>> [0.11986537, 0.33761517, 0.9429097 ],
>>> [0.18657006, 0.892559 , 0.53934224]]),
>>> array([[0.14092422, 0.80219698, 0.07455064],
>>> [0.94045858, 0.95392858, 0.91486439],
>>> [0.60754485, 0.17052412, 0.06505159]]),
>>> array([[0.37454012, 0.95071431, 0.73199394],
>>> [0.59789998, 0.92187424, 0.0884925 ],
>>> [0.11959425, 0.71324479, 0.76078505]])]
"""
if num_source_elems is None:
num_source_elems = len(source_list)
if seed is not None:
np.random.seed(seed)
random_elems_indices = np.random.choice(range(num_source_elems), size= cardinality_of_np_arrays * number_of_np_arrays, replace=False)
random_elems = np.array(source_list)[random_elems_indices]
# Split random_elems into sets
sampled_np_arrays = [random_elems[i * cardinality_of_np_arrays:(i + 1) * cardinality_of_np_arrays] for i in range(number_of_np_arrays)]
return sampled_np_arrays