[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
/ \( m7 D0 w: N: }4 d: I( i6 XDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
( J7 e  S% s9 Z; v  ^n = 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))
  p$ C3 r) _7 `( t! dReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
% }# ]  ~& c- }% @7 }1 GDim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
( C- {  x& d# m+ KReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
For i = 1 To n
8 `( }! U5 M9 n2 }6 ~' EFor j = 1 To n
- j* y, i1 l6 p3 ?! ba2(i, j) = a(i, j)
+ i0 _! r6 M/ G8 N  f" z1 eNext
1 k; j. Q0 K0 Q3 l, {% ~) tNext '将a()的值全部赋给a2()
0 }. Y5 \- s9 W. }9 B8 c4 h) Im = 0
D = 1
ReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
5 x- b) {7 T3 S/ E/ V9 JFor 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"))
% L( _8 v6 J# Y; I* d% {( aFor j = 1 To n
9 ~( V- e  P0 k! z! Z0 i0 ?" ma(i, j) = Val(Left(s, InStr(s, " ")))
% Y) U. t( @( L* y, [0 Ws = Trim(Right(s, (Len(s) - InStr(s, " "))))
* [3 v& E0 w+ x" ~1 u1 x: y+ Y' aPrint a(i, j);
Next
a(i, n + 1) = Val(s)
2 t% d3 `) [( W7 ^" nPrint a(i, n + 1);
: Z# Y2 ?6 [* u6 }! t2 APrint
. ~& x+ s; K" j( TNext

For k = 1 To n - 1 '开始消元
. a0 e/ S: S) k% H# `7 YIf a(k, k) = 0 Then
, ~0 B" }# `8 J, gMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
6 P* b# b, z& H+ k) S; a7 iExit Sub
Else
For i = k + 1 To n
/ C( s- k5 y1 ?. ~1 w5 i( Ml(i, k) = a(i, k) / a(k, k)
: `0 ^6 s4 q  K9 f( oFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
9 a) x3 b+ T7 o) mNext
Next
; F" A- y) T, \& Q  [/ }. ED = D * a(k, k)
" ~! ^4 K+ ]& p9 bEnd If
/ q# ^1 z% Q) l' r& a0 T0 d2 RNext k '消元结束
If a(n, n) = 0 Then
) M0 I: i% i' S" ^1 a; r' eMsgBox "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
& O& J6 w* d  P# oElse
0 f$ B8 C* N- |3 w+ d# C* P2 S, G/ vD = D * a(n, n)
End If
Print "--------------------------------"
1 L$ N; v. C9 e% r8 vPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
, h# H0 s8 G4 M0 T4 u  hFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
m = m + a(k, j) * x(j)
: o6 i$ a8 p5 ?. f. f" Y+ g. z* {Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
* d( ^$ F; ~( o) ~Next k '结束回代

7 E; ]  ~, q2 N; R2 tPrint "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
, Q% y! R; t8 v, Y2 sPrint
8 L7 i/ u/ ~9 U; A4 IPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
5 d) m1 T8 ?3 `5 G! HPrint "其中各行Ax-b="
Print
0 Y" s+ L" h" s0 C& U! UFor i = 1 To n
4 N0 Y' h' ~  ^/ @t = 0
* n# k% q" w( b( L* ]$ ZFor j = 1 To n
2 e; L" M8 r! @2 h, i% bt = t + a2(i, j) * x(j)
. N. k+ u' i, a$ MNext j
t = t - a2(i, n + 1)
, _7 h; F4 Y6 o. Q, CPrint Spc(5); "第" & i & "行："; t
8 d! }! [0 d  \' L- g* G6 ^' p% NPrint
Next i

End SubPrivate Sub gauss_Click() '高斯消去法
Dim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
n = 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))
" J7 L" U% B9 H0 }/ u: OReDim Preserve a(1 To n, 1 To n + 1)
9 Z2 T& k) C. Y- QReDim 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
9 y6 s0 h* w% {% F' Y0 vReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
7 V% x( c% u6 x/ HFor i = 1 To n
. y+ W7 B& q1 q# T6 aFor j = 1 To n
) K0 q6 _  T* p8 P& V& `# \* sa2(i, j) = a(i, j)
) W' v1 _! k2 JNext
Next '将a()的值全部赋给a2()
m = 0
( W+ V) T4 J* V/ }/ b' CD = 1
ReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
3 K3 y7 j1 R) eFor 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"))
. l( n! a3 F% ]6 cFor j = 1 To n
9 z1 \* v! g" X; |7 K8 {9 m8 Sa(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
# ^/ A" X& `+ \* I  C/ @Print a(i, j);
- A0 \- x7 Q# w6 c: \! eNext
a(i, n + 1) = Val(s)
: I+ y, n% p; h& GPrint a(i, n + 1);
Print
. e9 z, g; J$ b7 mNext

6 q1 N3 v8 c1 w6 ~( Y1 KFor k = 1 To n - 1 '开始消元
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！"
$ b( |3 w& D, h( N! L( E. fExit Sub
- V7 Q; @! G- I) hElse
1 F2 h2 o* d2 E5 w$ IFor i = k + 1 To n
# Z% \4 f' D, f+ o3 [' P9 Bl(i, k) = a(i, k) / a(k, k)
! T9 C' o) C4 @0 c  w0 B/ a; kFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
Next
  ]# x+ t$ F0 X  ^5 |- J# s. `0 R: j9 CD = D * a(k, k)
End If
Next k '消元结束
If a(n, n) = 0 Then
& g8 h9 R! I% DMsgBox "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 "--------------------------------"
4 H) }! n4 r$ X7 _# a3 R" @Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
; n+ N) ~0 Z% k8 I0 OFor j = k + 1 To n
+ P5 X  O! r. v! l* Nm = m + a(k, j) * x(j)
% ^. k0 |) E6 UNext j
' j) m/ a; k: `- u2 L* ]3 W( Q# B3 j9 kx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
, ^6 f+ D% b4 [; y4 P3 D  G) d( \+ m  oNext k '结束回代
, Q+ a3 K, _' Y$ ~
Print "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
  @8 @6 }5 a; d1 K7 [Print
3 y7 x/ f) F. m/ ]/ GPrint "X(" & k & ") = " & x(k)
Next k
8 @" r7 R! W! `, N2 ]Print "--------------------------------"
Print "其中各行Ax-b="
5 ?, |- u) T6 }) a2 `Print
! l* U1 w; ?+ U- t' Y/ xFor i = 1 To n
- V* C  h6 k- F! u- c" g, et = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
  p8 P# N9 t  G9 J; w. Nt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
3 [, K2 q& I$ ?# s! s2 \Print
6 O: e" D$ X, ]  @. P% U+ uNext 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