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# scipy.special.boxcox1p

scipy.special.boxcox1p(x, lmbda, out=None) = <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:
    x array_like

      Data to be transformed.

    lmbda array_like

      Power parameter of the Box-Cox transform.

    out ndarray, optional

      Optional output array for the function values

  Returns:
    y scalar or ndarray

      Transformed data.

  Notes

  Added in version 0.14.0.

  Array API Standard Support

  `boxcox1p` has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable `SCIPY_ARRAY_API=1` and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

  Library | CPU | GPU
  --- | --- | ---
  NumPy | ✅ | n/a
  CuPy | n/a | ✅
  PyTorch | ✅ | ⛔
  JAX | ⚠️ no JIT | ⛔
  Dask | ✅ | n/a

  > See Support for the array API standard for more information.

  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])