llLog
Revision as of 08:53, 16 June 2011 by Strife Onizuka (talk | contribs)
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Summary
Function: float llLog( float val );| 265 | Function ID |
| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a float that is the 
natural logarithm of val.
If val <= 0 return 0.0 instead.
| • float | val |
To get the base 10 logarithm use llLog10.
Caveats
Examples
<lsl> default {
state_entry()
{
float num1 = llFrand(100.0);
llOwnerSay("The natural logarithm of " + (string)num1 + " is " + (string)llLog(num1));
}
} </lsl> <lsl> 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
}
}
</lsl>Notes
There are only two log functions llLog and llLog10. Errors introduced as a result of floating-point arithmetic are most noticable when working with logarithms. llLog should be used instead of llLog10 when converting the base of the logarithm. <lsl>float LogBaseN = llLog(value) / llLog(Base); //This technique introduces errors but is the only way</lsl>
If Base is a constant, your script will run faster if you calculate it's log and divide by that constant instead.
| Number | logarithm |
|---|---|
| 2 | {{#ln:2}} |
| 4 | {{#ln:4}} |
| 8 | {{#ln:8}} |
| 10 | {{#ln:10}} |
| 16 | {{#ln:16}} |
| 32 | {{#ln:32}} |
| 64 | {{#ln:64}} |
| 128 | {{#ln:128}} |
| 256 | {{#ln:256}} |