Delaunay triangulation in SciPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Delaunay class from scipy.spatial.

SciPy

from scipy.spatial import [1]

points = [[0, 0], [1, 0], [0, 1]]
delaunay = Delaunay(points)

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ADelaunay

BVoronoi

CKDTree

DConvexHull

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Voronoi instead of Delaunay

Using ConvexHull which is for convex shapes, not triangulation

Forgetting to import from scipy.spatial

The Delaunay class from scipy.spatial is used to perform Delaunay triangulation on a set of points.

2fill in blank

medium

Complete the code to create a Delaunay triangulation object from the points array.

SciPy

import numpy as np
from scipy.spatial import Delaunay

points = np.array([[0, 0], [1, 0], [0, 1], [1, 1]])
delaunay = [1](points)

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AKDTree

BVoronoi

CConvexHull

DDelaunay

Attempts:

3 left

💡 Hint

Common Mistakes

Using ConvexHull or Voronoi instead of Delaunay

Passing points incorrectly as a list instead of numpy array

To perform Delaunay triangulation, you create a Delaunay object by passing the points array to it.

3fill in blank

hard

Fix the error in accessing the indices of the simplices (triangles) from the Delaunay object.

SciPy

import numpy as np
from scipy.spatial import Delaunay

points = np.array([[0, 0], [1, 0], [0, 1], [1, 1]])
delaunay = Delaunay(points)
triangles = delaunay.[1]

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Asimplices

Bvertices

Ctriangles

Dindices

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'vertices' which is deprecated

Trying to access 'triangles' which does not exist

Using 'indices' which is not an attribute

The simplices attribute of a Delaunay object contains the indices of points forming the triangles.

4fill in blank

hard

Fill both blanks to create a dictionary that maps each point to the number of triangles it belongs to.

SciPy

triangle_counts = {point: 0 for point in range(len(points))}
for triangle in delaunay.[1]:
    for vertex in triangle:
        triangle_counts[[2]] += 1

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Asimplices

Bvertex

Ctriangle

Dpoints

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'vertices' instead of 'vertex' in the inner loop

Using 'triangle' instead of 'vertex' to index the dictionary

Using 'points' which is the array, not the index

The simplices attribute gives the triangles. Each triangle has vertices, so we increment the count for each vertex.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps each point to the number of triangles it belongs to.

SciPy

triangle_counts = [1]: sum(1 for triangle in delaunay.[2] if [1] in triangle) for [1] in range(len(points))}

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Apoint

Bsimplices

Dvertex

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently

Using 'vertex' instead of 'point' in the comprehension

Using wrong attribute instead of 'simplices'

This dictionary comprehension counts how many triangles each point belongs to by checking membership in simplices.