[讨论]高斯消去法---这是用VB编的

god

Private 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))
ReDim Preserve a(1 To n, 1 To n + 1)
ReDim 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()
+ r! N8 _; X5 b/ N! `" aFor i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
1 F- ?8 e1 t5 z0 t- I- kNext '将a()的值全部赋给a2()
m = 0
D = 1
6 Y+ q& |: K7 p' r: Y0 j+ p( NReDim x(1 To n)
& y8 }/ R1 w- x* `Print "--------------------------------"
% q" s. b* d  APrint "您输入的增广矩阵如下："
For i = 1 To n
# R- k+ N8 P5 }5 C& Z* b7 ?' Rs = 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"))
For j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
# C- ]: L4 y% U( k( [Print a(i, j);
Next
a(i, n + 1) = Val(s)
% O- }0 C% g" Z' w, }Print a(i, n + 1);
Print
. {% Q8 {1 ^% L/ S8 hNext
3 y! |: n, \' @+ P" L4 S3 r1 O
2 E8 K, a/ R6 s% c% OFor k = 1 To n - 1 '开始消元
. X" Q' r. x6 s$ Z+ \" RIf a(k, k) = 0 Then
; d* u! _2 I  c6 L' }. [MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
Exit Sub
Else
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
) h) p  u0 R, C1 }a(i, j) = a(i, j) - l(i, k) * a(k, j)
, c5 V; P+ t5 l; e- iNext
" C8 V4 ^+ V! C% a4 F3 {Next
5 G0 n* Z6 Y0 w% \% V9 i" M. o3 T/ \D = D * a(k, k)
+ c, c% U# W% y" b  m6 i. F. qEnd If
Next k '消元结束
# F+ E7 j8 y7 R( B* }If a(n, n) = 0 Then
9 C* s$ b4 ^9 p1 p- B& f# CMsgBox "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！"
; T2 e. w. f8 m: b% J9 aExit Sub
Else
D = D * a(n, n)
5 D# O7 D; B- g) G  mEnd If
' \/ K9 y* @( YPrint "--------------------------------"
Print "系数行列式的值是："; D
3 a5 x# V- x, D% o+ E. l" Mx(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
+ a( e: w/ t0 Y2 Y" F. M, uFor j = k + 1 To n
m = m + a(k, j) * x(j)
1 d+ o- u* W' R3 C) L* C8 M! ~: J1 iNext j
( V0 h2 V/ D! S! |. cx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
Next k '结束回代
- m+ D" a4 r9 \
Print "--------------------------------"
Print "方程组的解如下："

% C1 C; u4 y* E$ g7 t0 L0 b- wFor k = 1 To n
Print
% N/ A: S+ h: cPrint "X(" & k & ") = " & x(k)
$ R# e  ]+ u) {2 w+ y+ g3 eNext k
Print "--------------------------------"
# C( ~7 E; a, I( _3 tPrint "其中各行Ax-b="
5 W  T% Z" M/ X1 K3 o' p6 _Print
For i = 1 To n
t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
3 Z( }$ }1 N4 JNext j
$ b/ z- h: J2 z# }/ c6 Ht = t - a2(i, n + 1)
) I  X6 R+ y$ L4 H9 ZPrint Spc(5); "第" & i & "行："; t
1 f7 _# O" k6 N& c) i3 B, KPrint
Next i

) b1 j. |/ d; L" c6 y) JEnd SubPrivate Sub gauss_Click() '高斯消去法
* t& \3 v3 J8 ]7 BDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
( m2 s- p! \5 Q# _3 X2 i, S: P  p5 E9 Pn = 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))
- ]6 I$ ~: q  k+ `# f) uReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
( q2 Q7 Q7 p' d) h1 eDim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
  e6 H" G7 ?7 }/ _ReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
For i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
# n! i5 L' V& c+ jNext '将a()的值全部赋给a2()
$ ^& R' e) g+ Pm = 0
D = 1
% S8 U! Q; ~3 o/ ~/ F% j- NReDim x(1 To n)
0 K8 `) ~6 g; O" a1 D1 e  `Print "--------------------------------"
- _8 ^( |+ c, {* e: s8 Q1 r5 PPrint "您输入的增广矩阵如下："
$ Z4 l+ m. a  M; j" o6 }: PFor 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"))
For j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
* W( m4 K) n# Ea(i, n + 1) = Val(s)
- i1 y! V2 [; ~2 j5 o$ hPrint a(i, n + 1);
+ U9 l; R+ u7 A' }Print
( v, f1 C7 Y7 I. dNext
0 s  [8 W4 ~& X. P
% X: k! L: {" v6 S1 |5 ~) Q. a9 jFor k = 1 To n - 1 '开始消元
+ i" m" U) J( m" X: FIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
3 Q+ N! d  S' H1 V+ E6 HExit Sub
Else
# V- v# n3 N0 |" G/ Z$ ~. `For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
. E' r% I6 |* h6 C1 S7 ZFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
0 h1 d( j0 E: H+ h& ?9 n; o/ }Next
Next
D = D * a(k, k)
End If
* C" G; K0 C" |Next k '消元结束
7 y) ~* T2 g9 @* h& Y! aIf a(n, n) = 0 Then
9 t: T6 V% m: j6 ]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！"
! E5 L8 K) j1 K' A3 IExit Sub
# h6 y, U* E6 k" R8 Y. `. uElse
4 b3 t" W4 ~4 ?4 X1 l4 X2 OD = D * a(n, n)
End If
% I7 d' W9 S6 K8 c) i( NPrint "--------------------------------"
Print "系数行列式的值是："; D
; ?1 e7 c/ E9 o8 ?' Q5 d2 n! B8 [x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
3 v& F0 ?3 c# {$ gFor j = k + 1 To n
7 Q) y2 R- o* Y% K! `4 e& M: Gm = m + a(k, j) * x(j)
- W$ I1 G5 H- `9 J, s! CNext j
/ r* I1 ]' R  f7 z, ex(k) = (a(k, n + 1) - m) / a(k, k)
9 `2 |" r9 s7 a; u3 ~m = 0
9 [2 z4 [: \4 @% r/ B0 I- nNext k '结束回代

- v% Q8 T  `' W7 f% x$ L5 @Print "--------------------------------"
Print "方程组的解如下："
: ?$ |4 M8 z, c& b% F+ ^
4 s4 N  s$ D# t$ e' `For k = 1 To n
9 ]2 a8 |/ k. \/ C, d5 E2 OPrint
Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
+ y9 {6 @# W+ y; \+ ]$ kPrint "其中各行Ax-b="
Print
For i = 1 To n
- K6 ]+ p4 b& nt = 0
7 r8 {7 w: l7 h1 B! i7 m; ZFor j = 1 To n
t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
* _& h0 g9 W2 m7 XPrint
! r% _- |: H2 N& h0 eNext 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