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# numpy.log10

`numpy.``log10`(x[, out]) = <ufunc 'log10'>

  Return the base 10 logarithm of the input array, element-wise.

  Parameters: | x : array_like Input values.
  Returns: | y : ndarray The logarithm to the base 10 of x, element-wise. NaNs are returned where x is negative.

  See also

  `emath.log10`

  Notes

  Logarithm is a multivalued function: for each x there is an infinite number of z such that 10**z = x. The convention is to return the z whose imaginary part lies in [-pi, pi].

  For real-valued input data types, `log10` always returns real output. For each value that cannot be expressed as a real number or infinity, it yields `nan` and sets the invalid floating point error flag.

  For complex-valued input, `log10` is a complex analytical function that has a branch cut [-inf, 0] and is continuous from above on it. `log10` handles the floating-point negative zero as an infinitesimal negative number, conforming to the C99 standard.

  References

  [R46] | M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 67. http://www.math.sfu.ca/~cbm/aands/

  [R47] | Wikipedia, “Logarithm”. http://en.wikipedia.org/wiki/Logarithm

  Examples

      >>> np.log10([1e-15, -3.])
      array([-15.,  NaN])