scipy.special.boxcox1p

scipy.special.boxcox1p(x, lmbda) = <ufunc 'boxcox1p'>

Compute the Box-Cox transformation of 1 + x.

The Box-Cox transformation computed by boxcox1p is:

y = ((1+x)**lmbda - 1) / lmbda  if lmbda != 0
    log(1+x)                    if lmbda == 0

Returns nan if x < -1. Returns -inf if x == -1 and lmbda < 0.

Parameters

xarray_like

Data to be transformed.

lmbdaarray_like

Power parameter of the Box-Cox transform.

Returns

yarray

Transformed data.

Notes

New in version 0.14.0.

Examples

>>> from scipy.special import boxcox1p
>>> boxcox1p(1e-4, [0, 0.5, 1])
array([  9.99950003e-05,   9.99975001e-05,   1.00000000e-04])
>>> boxcox1p([0.01, 0.1], 0.25)
array([ 0.00996272,  0.09645476])