[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
5 E1 S; G9 d. k3 K* M& T" `: sDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
; P* W& M* z$ [) v9 ~7 M4 cn = Val(InputBox("请输入矩阵的阶数(即：方程组未知数个数)N", "方程的未知数个数n", 3))
" W3 h1 A- b( ~! q; BReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
$ K) k, f2 l  V& n& `! k. qDim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
; _2 M& Y, ]7 x) V+ ]$ T) ?$ l  MReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
0 p' B* I' |/ i* H* ]! p0 IFor i = 1 To n
% g" g1 l8 c9 {% `: b. Z! ?& Q% |For j = 1 To n
a2(i, j) = a(i, j)
8 w6 x6 D$ t$ I& z2 _Next
# j* X! R2 f0 X& s4 MNext '将a()的值全部赋给a2()
* U5 x) L) f/ F/ s/ t  wm = 0
# V$ d# N( [. U2 _/ [D = 1
ReDim x(1 To n)
Print "--------------------------------"
( r& D# t4 M9 t  v3 }" mPrint "您输入的增广矩阵如下："
For i = 1 To n
s = Trim(InputBox("请输入增广矩阵的第" & i & "行" + vbCrLf + "各元素之间请用空格分开", i & "行矩阵的输入"))
) R4 ]  X! r, }; D- MFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
8 m2 V$ B# m- m3 P. VPrint a(i, j);
Next
a(i, n + 1) = Val(s)
Print a(i, n + 1);
: d4 L9 u: C9 A3 G: I0 b7 L, MPrint
" z' Z/ N, D5 J4 M0 ^Next
! j" j' K+ C2 x1 G$ _" x
For k = 1 To n - 1 '开始消元
) X# d' m4 U) J% F. {" D% XIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
# `" o( O' K  U6 _3 P  ~Exit Sub
Else
$ C/ C9 D( h& y2 }! J0 h$ _" |For i = k + 1 To n
/ ]8 N1 @* Y3 l4 K* il(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
2 V; {* H6 A+ P8 ^# tNext
Next
% r$ T' W+ D1 Y% r- w8 DD = D * a(k, k)
& g. ]( ~* f5 v- d% c  h2 _; KEnd If
Next k '消元结束
: p9 C, O- X' Q- t6 f# IIf a(n, n) = 0 Then
! k) O5 h& Y( x$ ?3 [MsgBox "Sorry！“高斯法”对此矩阵无能为力！" + vbCrLf + "原因是：a(n.n)=0了", vbExclamation, "解不出呀！"
* l0 ~  R0 ?! _$ T' V# O7 h; s) L$ ]Exit Sub
Else
D = D * a(n, n)
* Z9 J3 I% |' XEnd If
3 h, G; ~9 g/ g2 Y3 I9 YPrint "--------------------------------"
Print "系数行列式的值是："; D
+ X" k1 h, F  u: O  tx(n) = a(n, n + 1) / a(n, n)
. @+ y, Q  I* M" G  P  L. HFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
2 B" d0 A9 ~+ J. ~% y; ^! [m = m + a(k, j) * x(j)
: [$ T  l$ r# i4 mNext j
x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
- z6 T) S+ P( v% j9 [7 z2 E5 u5 v# H: BNext k '结束回代

Print "--------------------------------"
' W1 z  x1 J( I. C: |  ~! D: @+ KPrint "方程组的解如下："
& M9 u4 w1 t6 X4 b' B
For k = 1 To n
Print
& P0 M0 Z8 }9 hPrint "X(" & k & ") = " & x(k)
Next k
! W: P1 c  o  O" DPrint "--------------------------------"
5 u( V; v. b4 Q& h. j  p6 [Print "其中各行Ax-b="
Print
9 ~3 x9 m6 V1 p: [) a6 sFor i = 1 To n
t = 0
For j = 1 To n
7 m" i/ o. R4 _7 N: Y$ }t = t + a2(i, j) * x(j)
& u3 N3 K& m9 BNext j
. a. Y7 f! K3 k1 q# \1 ut = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
5 P% p2 r* V. x5 `Next i
  t& X9 g: I$ o& Q! l& r
End SubPrivate Sub gauss_Click() '高斯消去法
- u. J1 K+ l) H0 A$ ~Dim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
, N3 `! c4 R( V7 @i = 1: j = 1
' f' A) [, _* L& g2 \4 v3 jn = Val(InputBox("请输入矩阵的阶数(即：方程组未知数个数)N", "方程的未知数个数n", 3))
7 f) `/ j* I, K: VReDim Preserve a(1 To n, 1 To n + 1)
5 v. k) ]$ a8 C; Z7 `7 y$ NReDim Preserve l(1 To n, 1 To n + 1)
Dim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
ReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
" l+ t- X2 d& h3 F/ N+ ?6 rFor i = 1 To n
For j = 1 To n
/ O# h5 z9 x/ _: a! {: F' na2(i, j) = a(i, j)
8 A" `- `6 }5 V" f* _& RNext
Next '将a()的值全部赋给a2()
m = 0
/ c4 {. n: J1 x' v1 Y0 @+ TD = 1
ReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
For i = 1 To n
0 H7 c" _  t$ W8 ms = Trim(InputBox("请输入增广矩阵的第" & i & "行" + vbCrLf + "各元素之间请用空格分开", i & "行矩阵的输入"))
/ {3 J' t" H  g/ tFor j = 1 To n
4 E* x' F6 _' }a(i, j) = Val(Left(s, InStr(s, " ")))
5 k! d6 B! O; B% a$ B1 \s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
" a! Z7 n% U: ~+ A5 KNext
- Z, h% V  Z5 V% qa(i, n + 1) = Val(s)
5 N" Z- U. `  }Print a(i, n + 1);
1 k' T  b9 D+ |# bPrint
Next

For k = 1 To n - 1 '开始消元
* r  A& z& j$ o" w( K  ]If a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
" F+ p' [# M& Q  _% H* vExit Sub
Else
For i = k + 1 To n
& h( Z- v& d( q0 _* r: @l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
- o/ j7 R) y9 D, H$ `Next
D = D * a(k, k)
End If
Next k '消元结束
If a(n, n) = 0 Then
/ J  B* c  k( M/ P, F* XMsgBox "Sorry！“高斯法”对此矩阵无能为力！" + vbCrLf + "原因是：a(n.n)=0了", vbExclamation, "解不出呀！"
Exit Sub
Else
D = D * a(n, n)
End If
Print "--------------------------------"
2 T. l3 _& {7 J* N1 c# Y( L* IPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
2 c1 Q7 [  [0 P6 c: ]8 L. pFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
: n4 D' v8 p" L8 k4 Jm = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
/ a9 E( @' `# U1 _; l9 Mm = 0
7 I" V/ k3 V2 a# _" ^Next k '结束回代

Print "--------------------------------"
4 z+ N3 x9 Y, z' T5 z# r% nPrint "方程组的解如下："
- [( |( p$ N1 V+ x7 Z
For k = 1 To n
Print
3 D: Y0 J7 N" K4 h- E$ Y; S5 Y. BPrint "X(" & k & ") = " & x(k)
- P1 e  F! f! n6 Y$ ?# [  cNext k
; c, N. s# s' A' d; R- A( {; wPrint "--------------------------------"
Print "其中各行Ax-b="
Print
For i = 1 To n
t = 0
0 Q, m0 ?) n5 ^7 a8 b. C! l% n6 ^For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
9 J: ?% Y6 B& O: {Print Spc(5); "第" & i & "行："; t
! b: d3 U: I6 n1 [$ @+ G$ ?Print
Next i

End Sub

ch123en123

下载学习哦

lq12131010

<p>您的程序我没看&nbsp; 但是我用FORTRAN 90 编过 </p><p>唯一注意的是高斯消法是有局限的 </p><p>1计算量大</p><p>2不能克服病态方程问题。</p><p>不知道您注意没有 </p><p>另我有FORTRAN 90&nbsp;的选主元高斯消去法的程序。</p>

zqyzixin

我也想了解了解！！！先顶一个