贴上本人自己写的模拟退火算法的源代码,开发环境 Visual Basic.net 2005) u4 q8 B2 u& r/ U3 U$ ~4 y& v: j, v5 L
觉得有用的给个回复,拉拉人气.., a# E5 }: j! N8 m1 J/ i7 }
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Public Class CSA# v) p$ M0 E8 U% H [$ f) G Y( g. o j
# O# ?( C; T! C$ l' q Public Function obFun(ByVal x As Double) As Double
. Z7 u1 {. L- g) v, w Return 2 * Math.Pow(x, 2) - x - 1
7 A5 }4 O2 Q( Q! Q) y9 X' C End Function; b3 Y1 `2 S7 o. s U
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''' <summary>* ^- O$ N2 t7 g: @( N) M! ?/ M
''' 传统的模拟退火算法
% j# E0 H/ k! y% W' K" I/ d& ]4 g/ _, G ''' </summary>
9 H- P# p- r4 r5 J' a9 a5 l* K* e. [! j ''' <param name="Ux ">参数的取值范围上限</param>
- C( L# I4 |* p) r ''' <param name="Lx ">参数的取值范围下限</param>' f9 H5 G( C+ ]1 ?! `( F2 }
''' <returns></returns>
& w- J& M9 O* D% a ''' <remarks></remarks>% W W1 Q4 G. }1 t
Public Function CSA(ByVal Ux As Double, ByVal Lx As Double) As Double
4 J* k# c* T& |+ h1 b Dim init_temperature As Double, total_numk As Double, step_size As Double '定义初始温度,温度k时循环总次数,步长
m* V7 z1 t7 }: a" V Dim x As Double, receivnum As Double '定义变量当前值,前一个值,内循环的接受数据
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'初始化SA参数
5 F p5 B `: A% o% t init_temperature = 0.01
+ p8 n0 w4 o$ R4 U total_numk = 1000- T0 t: o$ Q/ D, P
step_size = 0.001
5 A/ m8 P' `2 g! C# \ receivnum = 50' Q8 B; ~$ f0 B6 W% B6 ^
x = (Lx - Ux) * Rnd() + Ux '随机产生变量x! ^- I5 D/ T/ J$ I
7 I9 a `3 L- }+ q2 q5 Z Dim k As Integer = 0 '温度下降次数控制变量
: b! ?+ G4 B4 U; X% u: Y Dim temperature_k As Double = init_temperature '定义第k次温度9 Y+ d$ \% s2 r$ ?4 z
Dim best_x As Double9 N+ H8 X# ^ Q: x
Dim de As Double = 0.0. U9 [4 G. z! A
Dim fcur As Double = 0.09 O% Z: W6 @2 T' H7 M4 S( L
Dim xi As Double
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Dim fprevs As Double = obFun(x)
. r+ v$ O) ~" T- u2 E8 k& m2 K Dim xprevs As Double = x
& E% a$ A; o# X e: x+ g l! v 'SA算法核心; `5 c: Y3 G$ t- w; P8 S* ]
Do
Q- E w4 L n. i$ z 'xprevs = x '保留前一个变量值' N6 s# l: y9 n4 k
0 b, X9 q5 I, J2 j2 U '以下三个参数用于估算接受概率6 e# x- R/ J6 _# s, ]. u. U
Dim rec_num As Integer = 0 '接受次数计数器
6 U# y A( A/ h+ m% e1 K% E( p+ R Dim temp_i As Double = 0 '记录下面for循环的循环次数& ^2 I: X4 R. @
Dim temp_num = 0 '记录fxi<fx的次数
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For i As Integer = 1 To total_numk- G+ j* g9 L# p, j4 z) F6 Y
'产生满足要求的下一个数- R# m* `( h+ ]+ ~3 |9 Y O. {, }( w
Do
3 ]# Q3 j+ D/ G3 M# \3 D: h5 ~& H xi = x + (2 * Rnd() - 1) * step_size
" K6 {6 q* F8 C& j& n Loop While (xi > Ux Or xi < Lx)
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" g. C) e# ^" C. b* A4 I fcur = obFun(xi)
# r4 J( b" m! O5 x) N' U de = fcur - fprevs9 n, E- O* U% F, ]' Z
; U! b1 ~0 [3 ?( @ If de < 0 Then '函数值小的直接进入下次迭代% L- w2 V8 o) G
best_x = xi
5 N$ F3 |7 a) O$ I* P x = xi
3 _3 B: V$ X% z" D- k- G rec_num += 1; Q, L" o# h/ H6 P! r# H! W& b
temp_num += 1
v3 E7 a6 z, q fprevs = fcur
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Dim p As Double, r As Double# G1 _" l7 t" n+ `
p = Math.Exp(-de / temperature_k)/ U& B* j8 V; E4 X
r = Rnd()
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If p > r Then# E! p6 I* A* G t2 e. ]! }
'以概率的形式接受使函数值变大的数
# y$ i: Z7 M6 Y x = xi4 D. ~$ O" X7 [" c
rec_num += 14 k3 C. P- p( _0 V8 R0 G) o
fprevs = fcur8 }9 _0 |. Q7 d0 e9 q
End If% `8 W+ F& C3 R
End If2 F, S$ O4 G! T' _
If rec_num > receivnum Then
6 r8 D+ M. n+ g. m0 W0 O temp_i = i - 1
" i$ [5 C9 o6 N4 K# W Exit For
6 L6 A8 O9 m$ m/ p/ l) A End If7 H, k$ R. F7 ]# K! O, l
Next
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: a3 A2 I/ |. |8 w5 ^ k += 1
- z6 C7 A1 a9 o5 y* s2 _6 r temperature_k = init_temperature / (k + 1) '温度下降原则
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( n' V) J4 [1 A, r0 h) m R If Math.Abs(best_x - 0.25) < 0.00001 Then Exit Do
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Loop While (k < 5000 )
/ B$ @' X" J/ F, r$ {9 l xprevs = x
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- |+ z+ B' _5 {2 ~0 W0 D' N9 j) ^( Y Return best_x6 V! x, s& h3 w
End Function
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# f$ ]" C- E$ v% H& G, Y( ]" ], @End Class
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! P+ B' @" {1 H算法测试:
2 P3 ~) @; D+ y* @在窗口中添加一个按钮 4 X% ~0 `3 C2 ]4 f6 B; [
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click* _1 J/ X1 _" d+ @
Dim csa As CSA_Cnhup = New CSA_Cnhup
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3 z' c4 A* K0 ^' L8 B' o' H Dim x1 As Double, x2 As Double% A4 T1 G- j+ p4 ^! O4 |/ d
x1 = 2 'CDbl(InputBox("参数上限", "参数范围", 2) & " ")
; y3 w7 j% Z" ?! m! E x2 = -2 'CDbl(InputBox("参数下限", "参数范围", -2) & " ")
. E# C ^" Z* z. U Dim y As Double* a6 c, _, K% a8 p
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y = csa.CSA(x1, x2)
: V9 y# r! D+ E& d( f8 ? Debug.Print("(" & y.ToString & "," & csa.obFun(y).ToString & ")"); j! g [! |% x) X4 P$ o4 d
Next5 i3 L8 ^3 k3 W8 b
Debug.Print((New System.Text.StringBuilder).Append("-", 60).ToString)( q: i: l, _9 K0 b0 P. V
End Sub $ c9 U% I ?% G I' a: ` @. V" Q' B
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