[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))
3 b( _' y' K+ C# a# F9 SReDim Preserve a(1 To n, 1 To n + 1)
' h5 z1 ?; @9 i* E& A+ P8 PReDim 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
8 O5 D" B; Q2 m1 u( l  x, x  c3 r: OFor j = 1 To n
3 Y5 ]. }- ?! ]$ }a2(i, j) = a(i, j)
Next
0 ]' ~# P4 f) p4 S, R+ O& N. ~* e6 kNext '将a()的值全部赋给a2()
9 ]5 `4 }3 a3 m: \( C8 h* W+ ~3 Bm = 0
D = 1
" {+ e4 K) N% gReDim x(1 To n)
Print "--------------------------------"
/ a- Q+ j0 e8 Q* l' j+ v$ k2 pPrint "您输入的增广矩阵如下："
( B6 s6 S: I! [* V8 H3 U# p3 `3 cFor 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, " ")))
, H& s$ q! {. @s = Trim(Right(s, (Len(s) - InStr(s, " "))))
$ b7 I* n4 f; T, cPrint a(i, j);
  c) k% S: H( g% B, m! fNext
0 _9 S" y! ]- G: z' K! Ga(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next
/ D" W2 j4 D# i! Q3 R
: k3 T: v/ X! w' PFor k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
. o  p# y  S1 m; \MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
Exit Sub
& Q* E3 m; g5 z$ S7 qElse
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
2 X% g5 |) \' `: e; AFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
) b1 z1 L5 F5 e6 @, BNext
Next
D = D * a(k, k)
End If
Next k '消元结束
, A* p* {' }2 a' O& r* o( m4 W% |: G- tIf 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！"
$ _# p) t( N2 C# Z& kExit Sub
Else
0 Q7 @% H- f: Z, fD = D * a(n, n)
% Y% I0 j4 s" X" ^End If
Print "--------------------------------"
Print "系数行列式的值是："; D
- h) k( @+ v6 Z* fx(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
0 J. q. L: x% J3 v) M( ~& k) u0 XFor j = k + 1 To n
m = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
2 f- B. E" E2 U8 HNext k '结束回代
/ d$ ^9 n/ V, \' h/ ~6 i$ e$ `
' S' S" M4 j0 C# u6 @Print "--------------------------------"
/ B. s% [. f9 z  iPrint "方程组的解如下："
6 @  y* Z# m" _# d) e2 d
% s( c; Q4 t( p* [' r, RFor k = 1 To n
Print
* z5 ~4 U8 {3 P: ^Print "X(" & k & ") = " & x(k)
! J) ?- A9 ^' i$ x2 j' ONext k
2 G5 M  A* Y  L4 q% sPrint "--------------------------------"
* T8 H$ K8 k& f3 ]$ lPrint "其中各行Ax-b="
4 i! A7 f- s$ D9 Y5 G# [Print
For i = 1 To n
t = 0
2 T" K  F, {& ]) Z  yFor j = 1 To n
t = t + a2(i, j) * x(j)
, b6 Q( ^9 Z* [/ E( U5 ]Next j
1 j2 H! I- a) S- P, e" tt = t - a2(i, n + 1)
! a' S9 v, I! {: \# nPrint Spc(5); "第" & i & "行："; t
Print
Next i

4 O; `1 P9 h0 V- {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
8 r9 L$ t& [2 x+ W' Ei = 1: j = 1
* I7 t3 |( x3 F# n  d1 ]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))
% ^! k* T$ o9 J, Q7 J* _/ i/ J. \ReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
, r) b* A0 `8 ?% GDim 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()
/ s! i; _+ c/ D7 h  q5 T+ d. EFor i = 1 To n
5 P9 i0 \6 c' Z4 Q$ a+ NFor j = 1 To n
a2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
D = 1
7 `+ p* I3 Z* t; G' EReDim x(1 To n)
- }2 D% _+ \0 k! sPrint "--------------------------------"
Print "您输入的增广矩阵如下："
( z) x7 u6 ?$ b% B7 u+ F3 sFor 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"))
! ?. R$ t4 z0 U9 n+ GFor j = 1 To n
& H3 i8 B9 l$ ja(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
9 `9 z3 a, N: n, P) D2 ?" Z  ?# }a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next

For k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
) W0 g0 `8 _+ G! |MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
0 d/ A! W: U- }. p0 J/ {Exit Sub
Else
$ V8 a6 l- t: m- c; _2 s4 G0 }+ j: E% V$ vFor i = k + 1 To n
( A6 q2 \7 H/ O9 f) T  Ll(i, k) = a(i, k) / a(k, k)
( G/ I/ n8 r' b! \6 y9 ~2 F& QFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
& D: E& u  B" HNext
3 |6 W) v: X* u7 T# A) MD = D * a(k, k)
End If
Next k '消元结束
If a(n, n) = 0 Then
6 {/ u+ I. C( r# |( o" rMsgBox "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！"
6 _# {- L9 C/ T, c: ~8 cExit Sub
Else
D = D * a(n, n)
, f1 s2 z+ B* u) i( j) Z' jEnd If
. v4 `) z! g0 K, ~7 n2 [" u% lPrint "--------------------------------"
Print "系数行列式的值是："; D
/ v8 Q. a  e1 h0 K( M4 \" r4 _x(n) = a(n, n + 1) / a(n, n)
2 U. \7 O1 X. }# ?! [. x" FFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
, T1 |- ^. a/ J2 Em = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
) q6 j. _$ G! [; z, t4 M3 pm = 0
; c# {5 o; B- f4 N5 \. uNext k '结束回代

6 P0 W9 A* I' {" M( aPrint "--------------------------------"
; _  Z% H, q2 EPrint "方程组的解如下："
) P3 R4 R+ j2 H2 ?& G6 D$ U% c
, g% @$ W: q) \4 u! a: PFor k = 1 To n
; x1 P. H7 O% R. _1 j" e& g5 {Print
Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
Print
For i = 1 To n
, X& @1 Z* p& _1 bt = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
2 Y# ]) N% J5 s2 u0 S/ A/ b, F+ wPrint Spc(5); "第" & i & "行："; t
Print
Next i
% _7 j8 L! N& ]/ K+ |/ R' k% u- p+ n
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