Difference between revisions of "LlLog"
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{{ | {{LSL Function | ||
|func=llLog | |||
|func_id=265|func_sleep=0.0|func_energy=10.0 | |func_id=265|func_sleep=0.0|func_energy=10.0 | ||
|return_type=float|p1_type=float|p1_name=val | |||
|func_footnote=To get the base 10 logarithm use {{LSLG|llLog10}}. | |func_footnote=To get the base 10 logarithm use {{LSLG|llLog10}}. | ||
|func_desc | |func_desc | ||
|return_text=that is the {{Wikipedia | |return_text=that is the {{Wikipedia|natural logarithm|w=n}} of '''val'''.<br/>If '''val''' <= 0 return 0.0 instead. | ||
|spec | |spec | ||
|caveats | |caveats | ||
|constants | |constants | ||
|examples | |examples= | ||
<source lang="lsl2"> | |||
default | |||
{ | |||
state_entry() | |||
{ | |||
float num1 = llFrand(100.0); | |||
llOwnerSay("The natural logarithm of " + (string)num1 + " is " + (string)llLog(num1)); | |||
} | |||
} | |||
</source> | |||
<source lang="lsl2"> | |||
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 | |||
} | |||
} | |||
</source> | |||
|helpers | |helpers | ||
|also_functions={{LSL DefineRow||[[llLog10]]|}} | |also_functions={{LSL DefineRow||[[llLog10]]|}} | ||
Line 15: | Line 42: | ||
|also_events | |also_events | ||
|also_tests | |also_tests | ||
|also_articles={{LSL DefineRow||{{Wikipedia| | |also_articles={{LSL DefineRow||{{Wikipedia|Natural logarithm}}|}} | ||
|notes | |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. | ||
<source lang="lsl2">float LogBaseN = llLog(value) / llLog(Base); //This technique introduces errors but is the only way</source> | |||
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 | ||
|cat1=Math | |cat1=Math | ||
|cat2 | |cat2 |
Latest revision as of 12:19, 22 January 2015
LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
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
default
{
state_entry()
{
float num1 = llFrand(100.0);
llOwnerSay("The natural logarithm of " + (string)num1 + " is " + (string)llLog(num1));
}
}
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
}
}
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.
float LogBaseN = llLog(value) / llLog(Base); //This technique introduces errors but is the only way
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}} |