section_path: Calculation
section_name: Calculation
paragraph_text: Calculation
  
  Logarithms are easy to compute in some cases, such as log (1000) = 3. In general, logarithms can be calculated using power series or the arithmetic–geometric mean, or be retrieved from a precalculated logarithm table that provides a fixed precision. Newton's method, an iterative method to solve equations approximately, can also be used to calculate the logarithm, because its inverse function, the exponential function, can be computed efficiently. Using look-up tables, CORDIC -like methods can be used to compute logarithms by using only the operations of addition and bit shifts. Moreover, the binary logarithm algorithm calculates lb(x) recursively, based on repeated squarings of x, taking advantage of the relation log 2 (x 2) = 2 log 2 | x |. {\displaystyle \log _{2}\left(x^{2}\right)=2\log _{2}|x|.}