Numpy Exercise 1

Imports



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import numpy as np
%matplotlib inline
import matplotlib.pyplot as plt
import seaborn as sns



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import antipackage
import github.ellisonbg.misc.vizarray as va

Checkerboard

Write a Python function that creates a square (size,size) 2d Numpy array with the values 0.0 and 1.0:

Your function should work for both odd and even size.
The 0,0 element should be 1.0.
The dtype should be float.



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def checkerboard(size):
    """Return a 2d checkboard of 0.0 and 1.0 as a NumPy array"""
    board = np.ones((size,size), dtype=float)
    for i in range(size):
        if i%2==0:
            board[i,1:size:2]=0
        else:
            board[i,0:size:2]=0
    va.enable()
    return board
checkerboard(10)









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a = checkerboard(4)
assert a[0,0]==1.0
assert a.sum()==8.0
assert a.dtype==np.dtype(float)
assert np.all(a[0,0:5:2]==1.0)
assert np.all(a[1,0:5:2]==0.0)

b = checkerboard(5)
assert b[0,0]==1.0
assert b.sum()==13.0
assert np.all(b.ravel()[0:26:2]==1.0)
assert np.all(b.ravel()[1:25:2]==0.0)

Use vizarray to visualize a checkerboard of size=20 with a block size of 10px.



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va.set_block_size(10)
checkerboard(20)









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assert True

Use vizarray to visualize a checkerboard of size=27 with a block size of 5px.



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va.set_block_size(5)
checkerboard(27)









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assert True



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