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 20052 e0 m! {$ W& k
觉得有用的给个回复,拉拉人气../ {' E$ @- x X# I G' v- e' x
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* ~3 |9 y i# \+ ]! v" WPublic Class CSA: S$ b! k0 f$ c, ]$ v$ w8 }
6 K1 Y4 ?: ~, u( s2 U U Public Function obFun(ByVal x As Double) As Double
" J1 `- r: K$ r) Y; H# V5 U Return 2 * Math.Pow(x, 2) - x - 1( K% \1 ~- I; s0 R6 }% ]4 I( ~' V
End Function
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''' <summary>
1 j3 E2 B4 ^$ g! J ''' 传统的模拟退火算法% i& c/ ?- n5 s! [$ ?
''' </summary>4 e& k8 }# w: u( z1 P2 X
''' <param name="Ux ">参数的取值范围上限</param>
* z4 n; G& J) F+ a$ }; J ''' <param name="Lx ">参数的取值范围下限</param>; f+ G( S3 P8 h; }4 `6 t2 v
''' <returns></returns>
" a, Q! ?' V; I7 ^5 C' `5 }7 }0 f ''' <remarks></remarks>
2 Q. w1 X2 F, M6 `' }5 u Public Function CSA(ByVal Ux As Double, ByVal Lx As Double) As Double
! ^- |& O) s0 g! ] 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' j- m$ C! M+ q; p+ x
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2 I! b5 \3 m$ S1 v4 U5 ]- v$ }
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'初始化SA参数2 |& D j4 O6 i$ y6 q, X% I8 X8 }! F
init_temperature = 0.016 K/ T+ L \& [. k" J
total_numk = 1000
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receivnum = 500 F# U2 n- z" c0 F
x = (Lx - Ux) * Rnd() + Ux '随机产生变量x: _4 ?! n; `9 _9 L0 Z/ s, ^1 m( C/ Y
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Dim k As Integer = 0 '温度下降次数控制变量
9 W; s$ i+ C$ B/ A) y8 _, w; h3 X Dim temperature_k As Double = init_temperature '定义第k次温度7 V7 k6 L9 j' |2 F4 p
Dim best_x As Double: \* D$ v! u) |" a6 O
Dim de As Double = 0.0' H7 T: X/ u h- M9 w
Dim fcur As Double = 0.0
+ [2 J) W- F+ @ Dim xi As Double& K2 X3 Q: W, R0 X6 L3 w2 l
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Dim fprevs As Double = obFun(x)! p0 Q2 e$ ~. k2 _. ~3 |) O1 y
Dim xprevs As Double = x' S* X( s2 g B. q2 Y) F
'SA算法核心
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'xprevs = x '保留前一个变量值
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* |6 J6 ~( a( i5 f# W' [: w- [ '以下三个参数用于估算接受概率* U9 @- g' i; [/ C! t& i9 H7 E1 Y+ J
Dim rec_num As Integer = 0 '接受次数计数器
; o7 D" `. @% H Dim temp_i As Double = 0 '记录下面for循环的循环次数$ J v H" ~/ M( _2 c
Dim temp_num = 0 '记录fxi<fx的次数! p* d: {/ J* b! r; V0 z% L0 J7 W" |
, e+ u/ Q; {, ]& d+ o: B For i As Integer = 1 To total_numk
( @. n: X2 @- Y* G* j, i9 ^ '产生满足要求的下一个数' s+ g4 M) u i2 j* M4 P7 p$ L$ p+ k
Do, p# t8 o% ]9 C& n6 h( o5 j
xi = x + (2 * Rnd() - 1) * step_size
: j( \* O- z3 I7 |4 I Loop While (xi > Ux Or xi < Lx)& k' A/ x+ Z! j( k
7 u% ]5 l; m; U/ Z$ t fcur = obFun(xi)' H/ U) q# l/ g/ @& t3 z
de = fcur - fprevs
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8 ~ D6 X5 X- z- P! ] If de < 0 Then '函数值小的直接进入下次迭代
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x = xi8 k: G; I. K3 [0 T- Y/ O
rec_num += 1
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fprevs = fcur
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/ z1 r- b3 Z3 }, x( s1 b- i Dim p As Double, r As Double
% {5 s1 n4 l5 e0 Y9 U p = Math.Exp(-de / temperature_k); a' `- U" M6 A
r = Rnd()
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, @# f4 G* l7 H9 P! Z If p > r Then0 I8 d8 I9 `) Q# t. b; y
'以概率的形式接受使函数值变大的数* e. x$ T& r! l4 O# u* {. m
x = xi. o+ U9 M( \+ |; L5 D# Y
rec_num += 1
W9 E/ P; n5 U3 f) K) B fprevs = fcur" n6 o8 E/ I4 v
End If# z2 L: P3 P4 t; y; ^$ `7 ?: i
End If* p" ^) q) G4 Z
If rec_num > receivnum Then0 G0 G- g0 P0 c: S$ `8 ~7 |* A
temp_i = i - 14 r( Y; f+ D% o" q& U& r
Exit For5 S6 H5 u- u* K+ t K# }
End If+ i1 E' [- \; Y! s' Q0 O( u
Next3 O9 b) i! ?% m. {0 G
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k += 1: `; J4 _2 N+ x* m( o
temperature_k = init_temperature / (k + 1) '温度下降原则
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If Math.Abs(best_x - 0.25) < 0.00001 Then Exit Do7 @* R0 [# v7 F" Y/ k; N t
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Loop While (k < 5000 )+ B! L) f2 i4 _2 p+ z2 ^; u
xprevs = x
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Return best_x
$ @) u% u/ k8 ^- B End Function% d+ I* \% ~ u0 w5 N6 b/ x, [1 x6 M
& o; Q6 f( G8 C9 X- v# W8 bEnd Class
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! h- [# @* Z: [* i- G算法测试: 7 H3 F$ @; Z" b+ ` }$ z/ O) W: J
在窗口中添加一个按钮
9 c2 l2 H; t: e0 H" m# c! Q$ U \Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
3 a/ e% }5 s6 i2 ] m& e Dim csa As CSA_Cnhup = New CSA_Cnhup& t1 T1 `8 l) y M+ u
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Dim x1 As Double, x2 As Double* x8 `& Z4 b4 v2 c9 I# L0 |* r
x1 = 2 'CDbl(InputBox("参数上限", "参数范围", 2) & " "). T& b) E6 o# V2 ^& G( J
x2 = -2 'CDbl(InputBox("参数下限", "参数范围", -2) & " ")
& ]) M2 g1 \" q: i" n Dim y As Double6 @1 X/ R1 Q6 k5 ^2 K
% Q$ w( U8 ^" M3 ]0 l5 S0 z For i As Integer = 0 To 19
: m6 x- E8 F o0 y( P y = csa.CSA(x1, x2)& y9 z3 D9 l+ b
Debug.Print("(" & y.ToString & "," & csa.obFun(y).ToString & ")")2 H7 A9 K9 i% `; l$ p( X: }3 t
Next
; l5 v. a! L1 F' N8 L( m: C+ j Debug.Print((New System.Text.StringBuilder).Append("-", 60).ToString)
3 {4 t8 ?4 w! q! F+ OEnd Sub
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