TukeyBiweight.psi(z)
[source]
The psi function for Tukey’s biweight estimator
The analytic derivative of rho
Parameters: | z (array-like) – 1d array |
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Returns: |
psi – psi(z) = z*(1 - (z/c)**2)**2 for |z| <= R psi(z) = 0 for |z| > R |
Return type: | array |
© 2009–2012 Statsmodels Developers
© 2006–2008 Scipy Developers
© 2006 Jonathan E. Taylor
Licensed under the 3-clause BSD License.
http://www.statsmodels.org/stable/generated/statsmodels.robust.norms.TukeyBiweight.psi.html