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enter image description here In Figure 5.3, Pattern recognition and machine learning (Bishop), the author says he fitted 4 function: f(x) = x^2; f(x) = sin(x) ; f(x) = abs(x); f(x) = Heaviside(x), using 50 points chosen uniformly over the range [-1; 1]. And he did it with a 2-layer neural networks with 3 hidden units, and with "tanh" activation function. The problem is with the sine function: In the figure there are obviously a local minima and a local maxima, but we know that those 2 points are : x = pi/2 and x = -pi/2, and they are not in the range [-1; 1]. So how are we going to fit the sine function with the local minima (and maxima) if we don't even have any information about them ? Thank you very much

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There's nothing about this in the 2011 errata to Bishop's PRML. If you believe that this is an error, you could contact the author.

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As it appears in other scratches of code (see https://github.com/ctgk/PRML for Python), it's actually $sin(\pi x)$.

May you have a nice day!

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    $\begingroup$ Very good github page +1 $\endgroup$
    – Zhubarb
    Jul 9, 2018 at 10:59
  • $\begingroup$ But is this the official page? $\endgroup$ Jul 9, 2018 at 12:34
  • $\begingroup$ Not sure. Wouldn't think so...! But pretty good anyway. $\endgroup$
    – ailoher
    Jul 9, 2018 at 14:44

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