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Old 10-13-2012, 06:12 AM
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magdon magdon is offline
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Join Date: Aug 2009
Location: Troy, NY, USA.
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Default Re: Problem 3.3 Typo

A simple way to plot a nonlinear classification hypothesis, which is actually the way used for all the figures in the book, is the brute force approach. Construct a grid of points, for example:

x1={0,0.01,0.02,...,1}
x2={0,0.01,0.02,...,1}

So every pair (x1,x2) from each set is a point in 2 dimensions. Now, for every such pair, evaluate the hypothesis h(x1,x2) and plot a red point if h=-1 and a blue point if h=+1. Note h can be any hypothesis, 3rd order polynomial, etc.

It is slow but it works.

Quote:
Originally Posted by rpistu View Post
For part e, when plotting the data and the final hypothesis learnt from a 3rd order polynomial feature transform, the shape of the nonlinear hypothesis is almost like a line. Is that true? Actually, I didn't find an effective way to plot the nonlinear hypothesis.
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