Difference between revisions of "LlLog"

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|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.
|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>
<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.
{{{!}} class="sortable" {{Prettytable}}
{{!}}+Useful natural logarithms
{{!}}-{{Hl2}}
! 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}}
{{!}}}
|permission
|permission
|negative_index
|negative_index

Revision as of 08:53, 16 June 2011

Summary

Function: float llLog( float val );

Returns a float that is the "Wikipedia logo"natural logarithm of val.
If val <= 0 return 0.0 instead.

• float val

To get the base 10 logarithm use llLog10.

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.


Useful natural logarithms
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}}

See Also

Functions

•  llLog10
•  llPow
•  llSqrt

Articles

•  "Wikipedia logo"Natural_logarithm

Deep Notes

Search JIRA for related Issues

Signature

function float llLog( float val );