Error in Example 3.5

[surtich]

There is an error in the number of runs to reach the minimum using the coordinate descent algorithm for this equation:

g(w1, w2) = 2w1² + 2w² + 2w1w2

The minimum is not reached in just two iterations.

The problem is that you call the algorithm with integer values ​​for the initial estimate of the w vector.

But if you use float values instead:

w = np.array([3.0,4.0])
max_its = 5
weight_history,cost_history = coordinate_descent_for_quadratic(g,w,max_its,a,b,C)

You get the correct values:

[array([3., 4.]), array([-2.,  4.]), array([-2.,  1.]), array([-0.5,  1. ]), array([-0.5 ,  0.25]), array([-0.125,  0.25 ]), array([-0.125 ,  0.0625]), array([-0.03125,  0.0625 ]), array([-0.03125 ,  0.015625]), array([-0.0078125,  0.015625 ]), array([-0.0078125 ,  0.00390625])]```

[RezaBorhani]

@surtich Thanks for pointing this out! We've updated Figure 3.4 as follows