[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))
: l0 Y/ v/ P. f! i8 o; JReDim 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
5 Q, [1 y0 y; A9 J% M8 D' \ReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
! Y9 r+ f) c) c7 [For i = 1 To n
& a# a) @& e, k1 w; g* H2 q; SFor j = 1 To n
a2(i, j) = a(i, j)
2 [8 ]! y; H3 b) q5 DNext
) q4 [& m& l* `. \Next '将a()的值全部赋给a2()
0 o% K2 B( J  |- |; c" w1 i. z8 Bm = 0
D = 1
ReDim x(1 To n)
' q# h6 `! @1 s  j, R2 bPrint "--------------------------------"
Print "您输入的增广矩阵如下："
: F' O" ~) c& i% U7 a+ uFor 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"))
7 @  U8 }9 C) P* g, TFor j = 1 To n
5 W& x8 e; }/ N# s  J5 N- R; fa(i, j) = Val(Left(s, InStr(s, " ")))
" {2 \2 ~9 P" t0 G$ Ds = Trim(Right(s, (Len(s) - InStr(s, " "))))
+ [" W. i& _$ C6 hPrint a(i, j);
* E/ D. H3 X5 qNext
+ t/ E6 r6 v+ L; g9 R0 Ia(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
1 Y8 L3 l& S0 H5 F3 uNext

! V( e0 s: i7 ^1 L4 VFor k = 1 To n - 1 '开始消元
: _; o' z# U; e. y# C8 N6 gIf a(k, k) = 0 Then
% h5 f: B+ k3 `9 K# n  z' dMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
: y/ K; e8 P3 T% T! FExit Sub
8 M% i$ L" {! d; P9 uElse
& @, i; U7 x% H! ZFor i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
- W: Y- y: M+ I' d: bFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
Next
D = D * a(k, k)
End If
Next k '消元结束
If a(n, n) = 0 Then
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！"
Exit Sub
Else
D = D * a(n, n)
End If
1 ~; D+ ?: D0 {% C0 E  T6 |Print "--------------------------------"
' s1 c8 G/ C/ N; }Print "系数行列式的值是："; D
0 a) u, P1 V% \x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
! g; e2 D( Q5 oFor j = k + 1 To n
( [; B1 X9 Y6 w7 @# L6 W4 im = m + a(k, j) * x(j)
  H3 F7 S" b4 {Next j
4 C$ B# u# H& w+ @# S  u- c( ex(k) = (a(k, n + 1) - m) / a(k, k)
8 G( |* k- L3 J; e: j4 Jm = 0
Next k '结束回代
' U% B# n3 g0 k1 z. z
Print "--------------------------------"
Print "方程组的解如下："

  w# y2 }' ^0 F; Q  fFor k = 1 To n
/ P  E: p0 W, C" q" H/ EPrint
Print "X(" & k & ") = " & x(k)
6 J1 @! {; {; Q1 R: A7 JNext k
' S" k1 T" K- f4 P  `+ r$ uPrint "--------------------------------"
Print "其中各行Ax-b="
Print
For i = 1 To n
; k# X* J' I! K: ~1 x4 j8 o0 ut = 0
For j = 1 To n
  o8 o4 {( |5 v. |6 Dt = t + a2(i, j) * x(j)
Next j
( b) }. u/ |/ ]; N5 r. n: Et = t - a2(i, n + 1)
6 u+ U- E, A. i8 p: [( G5 C+ D8 qPrint Spc(5); "第" & i & "行："; t
Print
, H% a# \2 C+ a: J4 |Next i
# u8 Q5 u3 f. u$ }: C
, X; {8 n. F; F" @" SEnd SubPrivate Sub gauss_Click() '高斯消去法
7 M% Y7 b5 Z* J' K0 VDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
# X) i) d6 \3 G  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))
ReDim Preserve a(1 To n, 1 To n + 1)
- {; @# P. n: F8 z1 l. Q% z5 ZReDim 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()
For i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
5 q; \1 S! l# v- KNext
  p" ~* B2 x+ }/ K* rNext '将a()的值全部赋给a2()
7 }  a5 o% a1 d( x  M& E' }/ Zm = 0
* ~. }4 H8 l9 Y) d, zD = 1
$ ^' G/ ~' y. o& w7 M3 X, XReDim x(1 To n)
& m" t. J) e1 ?$ HPrint "--------------------------------"
# I7 d4 L- i9 U  V. D  QPrint "您输入的增广矩阵如下："
For i = 1 To n
  R# D: u& _, s/ b: C( J4 _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);
1 _% W5 G! O2 k3 N7 V- RNext
  v4 |& P! Z8 ]4 i& pa(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
, r5 j1 h' {5 i  W9 P! yNext
& A  u# A/ c6 ^. K6 `( y
: t6 ?5 ~! E; D. q6 q1 k4 YFor k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
7 ?. {/ |% r+ l( ]9 _7 vMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
( i! t7 F/ k4 \9 u5 C% g* N! UExit Sub
Else
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
6 {8 ~. M$ n0 {1 z! {+ VFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
6 q& e" g3 B$ h2 F1 l- m, |" gNext
% P' ?; O3 i0 n2 P0 q3 g, AD = D * a(k, k)
' p: t" H0 ?$ v+ o6 S' YEnd If
) @4 A+ L5 v. S7 E* F! P5 SNext k '消元结束
If a(n, n) = 0 Then
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！"
7 i" ^+ @0 e0 `4 K  J1 x# `Exit Sub
Else
8 E( V% b$ F; g* U* mD = D * a(n, n)
End If
Print "--------------------------------"
Print "系数行列式的值是："; D
1 F, F; @) V+ w& Z5 qx(n) = a(n, n + 1) / a(n, n)
7 Q' p2 @0 y/ v+ l+ JFor k = n - 1 To 1 Step -1 '开始回代
# x) P1 q. W) c# cFor j = k + 1 To n
m = m + a(k, j) * x(j)
Next j
; ?. P* M: ?+ J' h/ Jx(k) = (a(k, n + 1) - m) / a(k, k)
7 M3 i" L: o- [+ [: S/ d) mm = 0
Next k '结束回代
  t. o: i3 `# s5 d* d* a" C' B
0 i1 o: ?/ _$ Z, b( [: kPrint "--------------------------------"
! Q6 H- l# m$ {5 L2 D5 o) C7 R. WPrint "方程组的解如下："

" V" I4 n% ~3 M  }& X4 [For k = 1 To n
5 J7 W- U  s7 m4 j# r8 U# K2 [Print
Print "X(" & k & ") = " & x(k)
& {/ i' d7 H  |( r7 i1 r$ pNext k
( J; _* A: ?5 U) r0 uPrint "--------------------------------"
+ F. X2 X2 y! W) {' j' q, x  CPrint "其中各行Ax-b="
Print
For i = 1 To n
t = 0
For j = 1 To n
/ `5 O* i. }! @6 t0 ]t = t + a2(i, j) * x(j)
7 i9 @; p5 h9 D( u) V  i2 [) DNext j
t = t - a2(i, n + 1)
5 q6 `# }  ]7 R" n7 C% tPrint Spc(5); "第" & i & "行："; t
( Y0 @) ]; B$ Q' C3 |/ EPrint
Next i

; w6 T4 @! M+ ?2 S) z8 F4 @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