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' s5 ]% h( }: h- p. {
觉得有用的给个回复,拉拉人气..+ R' I2 J6 V" {8 I. r" n/ f- M; r! j2 L
4 L* u8 q% {) }) ]4 C
- K0 n2 w0 H' _
Public Class CSA
$ m8 J6 m. A0 f9 J. [& u" g( E
4 ~6 U. U6 x! m Public Function obFun(ByVal x As Double) As Double6 k4 O; @' v, B7 E8 [0 C
Return 2 * Math.Pow(x, 2) - x - 1
: r: \/ r* q2 L9 j6 p End Function
3 m7 W' y! d3 [: b$ B; a# H3 y, ]% j
. } B2 s1 v5 g9 C0 M- d ''' <summary>
! w5 _5 i" B; X, j ''' 传统的模拟退火算法
/ O( j% S6 f+ B1 | ''' </summary>
; C( R4 v5 u1 S, v, F* D ''' <param name="Ux ">参数的取值范围上限</param>
: s8 N! T' j) [, \& \ ''' <param name="Lx ">参数的取值范围下限</param>
8 ~% ]* W5 S+ x# @, p9 y ''' <returns></returns>
- ? u$ w! k9 L3 X1 S+ m9 k ''' <remarks></remarks>5 m3 @4 h {5 {$ x2 q2 V
Public Function CSA(ByVal Ux As Double, ByVal Lx As Double) As Double' J" H% `/ e- A- A( Z' `" d
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5 ^! Y& w$ A6 b, @# g% q3 [
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. R4 U, q$ T) x
. Z0 C( u+ `% a% t- }& v9 C '初始化SA参数
8 s- F- [7 u! E: ~ init_temperature = 0.01% {2 c( \' U9 J7 C! l* v
total_numk = 1000) o. M( H5 v( ~( Z
step_size = 0.001
8 D2 d) I7 u9 B* P receivnum = 50
8 ?. H: X/ S6 ]* w x = (Lx - Ux) * Rnd() + Ux '随机产生变量x
" ]8 b t, r* N) F$ |4 W9 y9 u7 {; x2 _
Dim k As Integer = 0 '温度下降次数控制变量
; O& _( R( o4 w1 `% G Dim temperature_k As Double = init_temperature '定义第k次温度7 s* {+ m# R0 o+ ~
Dim best_x As Double j. t4 y- a" D& W/ a, W
Dim de As Double = 0.0
; Y7 m. k8 a. X+ d z& h0 q1 K8 g Dim fcur As Double = 0.0% f, _2 W$ x% R! h f" K* r3 v
Dim xi As Double, b5 V j, P2 P3 L
' `3 a6 ?8 W G Dim fprevs As Double = obFun(x)
% Z2 ~5 _/ ?) Z3 c# A( ^5 a7 D, U Dim xprevs As Double = x* c4 @5 v; |, `* u, N6 h" O
'SA算法核心* o/ ^$ _/ X! _# _
Do
c8 H. e2 N# l7 s) G7 z8 W 'xprevs = x '保留前一个变量值, l& ]8 C% H' ?- A& z" |
0 w4 ?4 y: |! m) |! F" C4 n: W
'以下三个参数用于估算接受概率
% s( w5 O& h+ F+ g, E* D, U Dim rec_num As Integer = 0 '接受次数计数器8 v/ `8 o; k3 J. F7 j" N2 N. E
Dim temp_i As Double = 0 '记录下面for循环的循环次数
( `; b+ f6 H2 n$ j3 S& g0 ~- { Dim temp_num = 0 '记录fxi<fx的次数
4 x4 ~# V0 U+ y9 D0 H6 @
3 O+ G/ V0 L# c5 Q# f- { For i As Integer = 1 To total_numk; [1 s9 {1 Z$ v# I
'产生满足要求的下一个数
% t3 A8 J; E4 J$ x% v" j Do( h9 x J& _- l% M
xi = x + (2 * Rnd() - 1) * step_size
2 O) n" d7 @- I Y Loop While (xi > Ux Or xi < Lx)
' Q, g$ `' }$ P2 j! h/ E& l4 I' q/ a
fcur = obFun(xi)1 ^% I; _+ r/ Q3 E
de = fcur - fprevs: L4 h( R) `+ t3 Q5 e, K
. x W4 i8 q( Q5 p( j
If de < 0 Then '函数值小的直接进入下次迭代5 g# g/ G) i4 o$ B$ x G: U5 w
best_x = xi
3 a8 s, p9 @9 N+ m) [9 W @ x = xi. w! D% V" N* v
rec_num += 1
$ u$ u; Z! f! w/ C temp_num += 1. e0 t% b- I/ O) t
fprevs = fcur
4 h9 R1 r* D7 U2 B' z- ]9 Q Else @, A5 X- M& g
Dim p As Double, r As Double" U3 J' L$ R3 I" X* W6 L' R2 S
p = Math.Exp(-de / temperature_k)0 Y0 a/ S$ y6 n. H* d3 ~+ B. B( t
r = Rnd()
7 b# J& m# Z! h
2 q2 }7 n% d/ m: n$ X If p > r Then: k" N+ M* V6 i" h6 c, a4 b
'以概率的形式接受使函数值变大的数 I/ o% l. W4 k
x = xi5 w) A% h; ?% O& r1 o
rec_num += 13 Y( d: U* @) W \* ~
fprevs = fcur
6 ^: |2 \7 `6 N) [, V End If
# E5 G5 L! U" s: n5 ?/ q, f' P End If
& u4 ^+ u' m- e8 k5 d If rec_num > receivnum Then
, v9 B5 ?: k i U: E+ q temp_i = i - 1& u7 g g5 d+ f$ y" L) l) i) Y
Exit For0 I' q7 `9 }9 R/ c' m0 S
End If
- p' x5 @+ |1 I Next
1 S& c/ ]/ U' k. ~ X3 g6 E& K( `) {3 E7 J
k += 1, U: t" ]7 t+ @8 S% L A& k9 C
temperature_k = init_temperature / (k + 1) '温度下降原则
/ {7 r3 [- p9 @! }7 n* P! j0 y$ A1 n' i j" a' a0 Y8 y
If Math.Abs(best_x - 0.25) < 0.00001 Then Exit Do& v# \( o& A3 v+ b" e. H& K
! H8 {4 C8 ^, ?# m# b& Q
Loop While (k < 5000 )4 a8 G6 T* k& H0 G0 b9 o9 c
xprevs = x c% t7 c2 A1 c
# i% N- Y; Q, ~" ~( c
Return best_x& R8 Q x6 P3 \9 d( k
End Function
2 t9 s$ r7 a% b8 ~) \) w2 p" R( P5 ^1 ^. J& H
End Class
( v7 z" N( ~# i' L( r }
7 e x0 {9 ^4 A7 s% Z: I; m# E ; x9 P6 J: K0 }
算法测试:
3 T' I5 r8 {9 t2 u; r7 ^4 N在窗口中添加一个按钮 ) g; I4 \: d; X( i4 ~* ~' h6 F/ }
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click6 w4 j* |9 z% z8 I* p. C4 O. ^: ^
Dim csa As CSA_Cnhup = New CSA_Cnhup
$ B" f. b0 `5 T' m4 E0 O7 s: E. K& u' N. C
Dim x1 As Double, x2 As Double" l \1 L3 \+ m8 j
x1 = 2 'CDbl(InputBox("参数上限", "参数范围", 2) & " ")
+ A/ o6 h+ i; l x2 = -2 'CDbl(InputBox("参数下限", "参数范围", -2) & " ")- B( u/ ~! C5 t N/ _
Dim y As Double; Z; @' S% y( |& ?, L
# Y, \5 n: A# h+ ~$ e
For i As Integer = 0 To 19
8 g. i; P: K3 n9 }+ |( j y = csa.CSA(x1, x2)
7 _3 e3 E: k! R/ L Debug.Print("(" & y.ToString & "," & csa.obFun(y).ToString & ")")* U8 @( S3 b8 l4 [' U
Next
6 [6 O3 e/ z, X/ g Debug.Print((New System.Text.StringBuilder).Append("-", 60).ToString)
* O3 \( k/ i2 ]0 a5 L7 n% oEnd Sub
0 C. T2 w' N& ~0 w; T) ?6 |. W) [
|