[Numpy-discussion] Combining Sigmoid Curves

Christopher Barker Chris.Barker@noaa....
Fri May 2 17:59:55 CDT 2008

Anne Archibald wrote:
> 2008/5/2 Rich Shepard <rshepard@appl-ecosys.com>:
> No, no. You *want* scaled_x to range from -1 to 1. 

Why not just scale to -pi to pi right there?

(The 0.998 is because you didn't include the endpoint, 100.)

Which is why you want linspace, rather than arange. Really, trust me on 

If the cosine curve isn't right for you, a little create use of np.where 
would let you do what you want in maybe another line or two of code. 
Something like:

y = np.where( x < 0 , Leftfun(x), Rightfun(x) )

or just compute one side and then flip it to make the other side:

y = np.zeros_like(x)
y[center:] = fun(x[center:])
y[:center] = y[center+1:][::-1] # don't want the center point twice

if it's symetric anyway.


Christopher Barker, Ph.D.

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception


More information about the Numpy-discussion mailing list