Positional Arguments in numpy.piecewise()

Asked Jul 10 '23 at 14:50

Active Jul 10 '23 at 21:34

Viewed 43 times

I am trying to create a piecewise function using numpy, and I followed the examples in its documentation, however, only the outer bounds return the correct values.

The function I have for the 44 < x < 58 returns 0, while it should return the value calculated in the cell below. I'm sure this is a simple syntax error, but I am having trouble seeing it.

x = 50
numpy.piecewise(x, [(44 < x) & (x < 58), x <= 44, x >= 58], [(0.4876 +0.1201*math.cos(x*1.017) + 0.5111*math.sin(x*1.1017)), 0, 1])

Edit: I updated the syntax of the boolean and am still getting the same error.

edited Jul 10 '23 at 21:34

jared

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asked Jul 10 '23 at 14:50

Kat Neumann

Please insert code as text and not as an image. – jared Jul 10 '23 at 14:54
`a < x < b` does not work for numpy. Use `(a < x) | (x < b)`. – Frank Yellin Jul 10 '23 at 14:55
@FrankYellin I assume you mean `&` not `|`. – jared Jul 10 '23 at 14:56
Does this answer your question? [Multiple Pieces in a numpy.piecewise](https://stackoverflow.com/questions/19578185/multiple-pieces-in-a-numpy-piecewise) – jared Jul 10 '23 at 14:58
piecewise returns an array of the SAME TYPE as x; x being an int, it returns an int... Try with x = 50.0 – Swifty Jul 10 '23 at 14:59
@Swifty That worked! Thank you. – Kat Neumann Jul 10 '23 at 15:02
@jared, D'oh. Of course. Thanks. – Frank Yellin Jul 10 '23 at 15:07
Also, if you're using numpy, use `np.sin` and `np.cos` rather than the math library's functions. The numpy versions can work with numpy arrays. – jared Jul 10 '23 at 21:35

Positional Arguments in numpy.piecewise()

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