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# numpy.logaddexp

`numpy.``logaddexp`(x1, x2[, out]) = <ufunc 'logaddexp'>

  Logarithm of the sum of exponentiations of the inputs.

  Calculates `log(exp(x1) + exp(x2))`. This function is useful in statistics where the calculated probabilities of events may be so small as to exceed the range of normal floating point numbers. In such cases the logarithm of the calculated probability is stored. This function allows adding probabilities stored in such a fashion.

  Parameters : | x1, x2 : array_like Input values.
  Returns : | result : ndarray Logarithm of `exp(x1) + exp(x2)`.

  See also

  `logaddexp2`
    Logarithm of the sum of exponentiations of inputs in base 2.

  Notes

  New in version 1.3.0.

  Examples

      >>> prob1 = np.log(1e-50)
      >>> prob2 = np.log(2.5e-50)
      >>> prob12 = np.logaddexp(prob1, prob2)
      >>> prob12
      -113.87649168120691
      >>> np.exp(prob12)
      3.5000000000000057e-50