function complexLog2Number (x) {
    return _log2Complex(new Complex(x, 0))
  }
Calculate the 2-base of a value. This is the same as calculating `log(x, 2)`.

For matrices, the function is evaluated element wise.

Syntax:

   math.log2(x)

Examples:

   math.log2(0.03125)           // returns -5
   math.log2(16)                // returns 4
   math.log2(16) / math.log2(2) // returns 4
   math.pow(2, 4)               // returns 16

See also:

   exp, log, log1p, log10

@param {number | BigNumber | Complex | Array | Matrix} x
           Value for which to calculate the logarithm.
@return {number | BigNumber | Complex | Array | Matrix}
           Returns the 2-base logarithm of `x`