[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
/ ?# j9 v) a/ K" d  Vi = 1: j = 1
8 G: K" S# Y& }0 J; ?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)
/ q0 D7 {$ t' k: @, M7 C3 fReDim Preserve l(1 To n, 1 To n + 1)
0 m! w& G( r8 I& {" g/ n) ZDim 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()
/ e; f  `7 e) ^" u6 }For i = 1 To n
For j = 1 To n
1 S" L- }+ a) F7 Na2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
D = 1
5 u% X2 l; E2 ~( l: w" G1 e5 JReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
For i = 1 To n
; |" q# m5 i  g# Z4 Xs = 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, " ")))
+ C5 l# W2 V, ~$ j! fs = Trim(Right(s, (Len(s) - InStr(s, " "))))
/ J: c+ ~! [/ p% H3 W; }Print a(i, j);
Next
a(i, n + 1) = Val(s)
* L) v- d; Z! q9 bPrint a(i, n + 1);
* \* F# q0 `3 f. uPrint
Next
7 w9 ^% a: z6 i" f
6 r  |1 c  d+ Q$ |( e& ?For k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
: Z) e4 z  q5 UMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
Exit Sub
Else
' r; V$ J) X* U, U% H% U% n6 }9 X( YFor i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
5 X6 L3 F! _) g0 G! @For j = k + 1 To n + 1
/ j  c! K. K( M$ va(i, j) = a(i, j) - l(i, k) * a(k, j)
. Y1 P* _* H1 B- [& qNext
6 P9 {# O) q8 @# }Next
D = D * a(k, k)
. U6 ~! K( J! }* n; W6 Z( dEnd If
' `. t- X' c% [  E1 oNext k '消元结束
0 y6 ]+ R8 @# v- y* ^% yIf 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！"
' c( e; K+ M0 @( T0 UExit Sub
1 n8 x: r* v$ c/ \* n9 a; {Else
D = D * a(n, n)
End If
Print "--------------------------------"
Print "系数行列式的值是："; D
& U2 J& ~4 o! z6 d6 X8 m0 k+ {x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
2 o$ d9 f9 d, ^0 Lm = m + a(k, j) * x(j)
* p% I+ o$ M8 t& `) `$ H; SNext j
+ H6 m5 \7 H8 `x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
8 t' M2 o5 [5 wNext k '结束回代
0 l' a5 s- B5 o; e( G/ L6 P- _. d  |+ D
/ G- M" }8 \' V" z- aPrint "--------------------------------"
Print "方程组的解如下："

2 N! Z6 c9 x" a; G2 fFor k = 1 To n
Print
9 U: C6 w  f/ _. j& N8 P% q. }) ZPrint "X(" & k & ") = " & x(k)
Next k
: B  M' y% U9 X  k7 sPrint "--------------------------------"
/ ?$ g4 F! S. KPrint "其中各行Ax-b="
8 T5 |5 H9 n4 `" EPrint
# m) b6 ]2 K3 }! @8 ^. |For i = 1 To n
t = 0
0 v+ x9 N6 c6 \3 g2 p; D! ^For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
; ]0 Q) q/ J1 z' ~t = t - a2(i, n + 1)
- e$ X. i. X" C2 P# DPrint Spc(5); "第" & i & "行："; t
/ A, l& k, F: Z# HPrint
" Z! h3 `$ f. S6 j+ S8 T8 f. tNext i
, k1 u& x, m  h
+ |/ M" _$ e/ `/ W0 z8 U0 REnd SubPrivate Sub gauss_Click() '高斯消去法
3 v( [4 M( X& {" N; R% d, FDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
! D. q9 `4 x( H% I4 W5 t  s7 m* ^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
7 X5 H4 E* s3 `6 u; OReDim 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
Next '将a()的值全部赋给a2()
m = 0
D = 1
ReDim x(1 To n)
$ r/ v0 w# L2 D- _4 R. I" H( WPrint "--------------------------------"
& z0 Q3 f' V- g; ]* l0 c9 tPrint "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"))
For j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
. p% J9 C( G0 S& |9 F+ Ws = Trim(Right(s, (Len(s) - InStr(s, " "))))
  _. W* V# D" g, l6 @- {Print a(i, j);
Next
) \7 B% C& }0 w4 l2 q  y$ Z0 z0 L) Wa(i, n + 1) = Val(s)
# z- I. S, B+ P. E" s" fPrint a(i, n + 1);
9 h# u- m+ p; h, A. f* gPrint
Next
" s5 u9 ^0 k& w$ E
For k = 1 To n - 1 '开始消元
' a" o( V1 i6 aIf a(k, k) = 0 Then
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
+ F/ \8 O, j; I7 |, yl(i, k) = a(i, k) / a(k, k)
- U& }! }) W7 L) @8 Z3 ~" L. YFor j = k + 1 To n + 1
* N. d. J2 R! X: {9 J9 ^- A6 ra(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
2 u" b0 p* U$ H) ]& H3 `Next
D = D * a(k, k)
: r: g( n" ~2 GEnd If
Next k '消元结束
If a(n, n) = 0 Then
. L6 B/ i% J; X& n, ?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！"
+ m! d3 g1 D/ p2 cExit Sub
5 c: |& e, d- U7 }& t1 xElse
" {  ]) a% P, j" `D = D * a(n, n)
End If
/ t( U% b3 L$ {& w3 O3 iPrint "--------------------------------"
# R% K/ O/ d% r9 ~3 c4 Y# ]+ PPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
5 [; ~/ M" b9 r( I9 U$ @% Y: e7 p& TFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
m = m + a(k, j) * x(j)
Next j
% S9 Y6 c+ h+ U8 E$ vx(k) = (a(k, n + 1) - m) / a(k, k)
' H7 F$ }! U& x" s% fm = 0
2 |' y4 u  \9 d, l' @  M: [Next k '结束回代
5 W. S; ~  G! G, e/ j- n. p1 Y# j" G
* Y$ {- F/ b5 [+ J; ]6 \8 Q( N5 _  SPrint "--------------------------------"
Print "方程组的解如下："
' q: l% `8 l3 N, G
For k = 1 To n
7 `2 O0 m3 g2 ?( k: g/ sPrint
% T2 i2 I- X7 A+ v$ YPrint "X(" & k & ") = " & x(k)
! u! y- [2 {( N" _) YNext k
3 O* D% V6 W6 u# o. hPrint "--------------------------------"
Print "其中各行Ax-b="
Print
1 x3 I$ {. {! g6 B+ p- G$ GFor i = 1 To n
( X; G0 \) n+ T  v1 c, nt = 0
For j = 1 To n
+ N9 G9 B! q. Bt = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
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