更改

[[文件:Flocking.png|缩略图]]

[[文件:Flocking.png|缩略图]]

== WHAT IS IT（鸟群模型） ==

== 鸟群模型 ==

This model is an attempt to mimic the flocking of birds. (The resulting motion also resembles schools of fish.) The flocks that appear in this model are not created or led in any way by special leader birds. Rather, each bird is following exactly the same set of rules, from which flocks emerge.

This model is an attempt to mimic the flocking of birds. (The resulting motion also resembles schools of fish.) The flocks that appear in this model are not created or led in any way by special leader birds. Rather, each bird is following exactly the same set of rules, from which flocks emerge.

== HOW TO USE IT（使用教程） ==

 

 

=== HOW TO USE IT（NetLogo使用教程） ===

First, determine the number of birds you want in the simulation and set the POPULATION slider to that value. Press SETUP to create the birds, and press GO to have them start flying around.

First, determine the number of birds you want in the simulation and set the POPULATION slider to that value. Press SETUP to create the birds, and press GO to have them start flying around.

== THINGS TO NOTICE（注意事项） ==

=== THINGS TO NOTICE（注意事项） ===

Central to the model is the observation that flocks form without a leader.

Central to the model is the observation that flocks form without a leader.

有时鸟儿会从鸟群中飞走。这是怎么发生的？为了观察这种现象，您可能需要放慢模型的速度或一步一步地运行它。

有时鸟儿会从鸟群中飞走。这是怎么发生的？为了观察这种现象，您可能需要放慢模型的速度或一步一步地运行它。

== 代码实现 ==

=== 代码实现 ===

[http://www.netlogoweb.org/launch#http://ccl.northwestern.edu/netlogo/models/models/Sample%20Models/Biology/Flocking.nlogo Netlogo Web - Flocking]<syntaxhighlight line="1" lang="lisp">

[http://www.netlogoweb.org/launch#http://ccl.northwestern.edu/netlogo/models/models/Sample%20Models/Biology/Flocking.nlogo Netlogo Web - Flocking]<syntaxhighlight line="1" lang="lisp">

turtles-own [

turtles-own [

</syntaxhighlight>

</syntaxhighlight>

== THINGS TO TRY（你可以试一试） ==

=== THINGS TO TRY（你可以试一试） ===

Play with the sliders to see if you can get tighter flocks, looser flocks, fewer flocks, more flocks, more or less splitting and joining of flocks, more or less rearranging of birds within flocks, etc.

Play with the sliders to see if you can get tighter flocks, looser flocks, fewer flocks, more flocks, more or less splitting and joining of flocks, more or less rearranging of birds within flocks, etc.

== EXTENDING THE MODEL（模型的延伸） ==

=== EXTENDING THE MODEL（模型的延伸） ===

Currently the birds can "see" all around them. What happens if birds can only see in front of them? The <code>in-cone</code> primitive can be used for this.

Currently the birds can "see" all around them. What happens if birds can only see in front of them? The <code>in-cone</code> primitive can be used for this.

== NETLOGO FEATURES（NetLogo默认设定） ==

=== NETLOGO FEATURES（NetLogo默认设定） ===

Notice the need for the <code>subtract-headings</code> primitive and special procedure for averaging groups of headings. Just subtracting the numbers, or averaging the numbers, doesn't give you the results you'd expect, because of the discontinuity where headings wrap back to 0 once they reach 360.

Notice the need for the <code>subtract-headings</code> primitive and special procedure for averaging groups of headings. Just subtracting the numbers, or averaging the numbers, doesn't give you the results you'd expect, because of the discontinuity where headings wrap back to 0 once they reach 360.