Log

You may be looking for Logging.

The Log internal function returns the natural logarithm of its argument. This is like the LN(X) function in mathematics. Do not confuse the BR LOG with the mathematical LOG base 10.

LOG(<positive number>)

The argument must be a positive number.

00010 print LOG(2.718)

produces the following output:

0.999896

However,

00010 print LOG(-3)

produces an error