In the PROMOTIC system it is better to use the Pm.LogN method.
n = Log(number)
|number||(Double) Number greater than 0|
The natural logarithm is the logarithm to the base e. The constant e is approximately 2.718282.
You can calculate base-n logarithms for any number x by dividing the natural logarithm of x by the natural logarithm of n as follows:
Logn = Log(x)/Log(n)
nLog10 = Log(x) / Log(10)