llLog
float llLog(float Value)Returns the natural logarithm of Value. Returns zero if Value <= 0.
Returns the base e (natural) logarithm of the specified Value.
Parameters
Value(float)
Basic usage to calculate natural logarithm:
default{ state_entry() { float num1 = llFrand(100.0);
llOwnerSay("The natural logarithm of " + (string)num1 + " is " + (string)llLog(num1)); }}Converting to arbitrary logarithm base:
float findexp(float result, float base){ return llLog(result)/llLog(base);}
default{ touch_start(integer total_number) { llSay(0, (string)findexp(8.0, 2.0)); // returns 3.0 }}There are only two logarithm functions: llLog and llLog10. When converting the base of the logarithm, use llLog rather than llLog10 as it introduces fewer errors. The general formula for converting to an arbitrary base is:
float LogBaseN = llLog(value) / llLog(Base);Note that this technique inherently introduces errors due to floating-point arithmetic, which are most noticeable when working with logarithms. If the base is a constant, your script will run faster if you pre-calculate its logarithm and divide by that constant instead.
Useful Natural Logarithm Values
Section titled “Useful Natural Logarithm Values”| Number | ln(Number) |
|---|---|
| 2 | 0.693147 |
| 4 | 1.386294 |
| 8 | 2.079442 |
| 10 | 2.302585 |
| 16 | 2.772589 |
| 32 | 3.465736 |
| 64 | 4.158883 |
| 128 | 4.852030 |
| 256 | 5.545177 |