[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))
, H% V& v+ d0 Y. TReDim 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()
For i = 1 To n
4 h( T5 B9 z6 N! @% A* a0 |9 RFor j = 1 To n
- \4 o0 V7 i# _- p" J# fa2(i, j) = a(i, j)
! w" e8 z2 Q! r0 s; p* CNext
Next '将a()的值全部赋给a2()
m = 0
4 i3 ~. H1 t! m4 M8 LD = 1
ReDim x(1 To n)
, c5 R! W- U2 f7 W1 aPrint "--------------------------------"
  g  _: y. k$ J, {Print "您输入的增广矩阵如下："
" D% Z9 P9 ^" [9 l$ yFor 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, " ")))
' J7 C0 R$ F: ~1 ns = Trim(Right(s, (Len(s) - InStr(s, " "))))
7 j% s6 c0 t) |( |; bPrint a(i, j);
$ A  v* C0 [+ k( y% j4 A6 JNext
* n, ~- k2 l( ^a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next
+ M# a% Z! ^) h
5 h0 s( @5 B+ `For 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！"
* M/ }9 z" s+ s0 y/ }Exit Sub
$ F9 N- w8 T+ w0 |3 G$ pElse
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
( \2 r/ @& y* S! l8 CNext
Next
D = D * a(k, k)
End If
Next k '消元结束
* R- F2 Q- k. kIf a(n, n) = 0 Then
* C' E2 \9 n2 u5 r3 sMsgBox "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
7 j5 G+ E" G7 o, |; N9 J/ qD = D * a(n, n)
End If
Print "--------------------------------"
Print "系数行列式的值是："; D
  N' A6 e4 J: \% T# @. z  Qx(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
9 M# ~5 C( B, W4 B5 sFor j = k + 1 To n
m = m + a(k, j) * x(j)
9 W9 s9 A. p' B' ?* H+ N- gNext j
( P/ T: y9 S% S4 ~* Vx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
$ W. i# s: }3 W2 r. |% N# WNext k '结束回代

* j" @. C+ s* N" rPrint "--------------------------------"
Print "方程组的解如下："
0 K: ?9 o% E3 k* Q7 m( v6 c/ r5 \
For k = 1 To n
4 b" w& e! C' \( J$ m" p8 qPrint
Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
8 \4 e; \( _" J# |2 ~: oPrint "其中各行Ax-b="
Print
For i = 1 To n
% E0 K1 j( j- |2 [t = 0
For j = 1 To n
0 R" S' Z( [# J9 Yt = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
! j; u1 M" P1 z$ r( Z1 G& O9 KNext i
6 D0 L( L" a' e7 g& @5 ]
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
# L; S) y6 {) b( e) Pi = 1: j = 1
8 @& i7 ?9 _* r8 ?4 X8 g1 ^/ Sn = 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)
6 f4 B+ u" r; U  c) |# vReDim 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
, M# w/ X% T0 ~3 w- hReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
For i = 1 To n
+ [7 l* h3 L; e$ T2 oFor j = 1 To n
a2(i, j) = a(i, j)
Next
2 A% o% d$ z  l$ r* h* dNext '将a()的值全部赋给a2()
m = 0
D = 1
ReDim x(1 To n)
4 }5 k- e% i9 n" WPrint "--------------------------------"
/ }" `2 \3 k9 l( v/ |% sPrint "您输入的增广矩阵如下："
* ]4 O1 \- U- ^+ b. M! p7 f2 j; oFor 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
% x1 D) t- o# x4 E% ~a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
+ X1 A9 e- \, \% w! e& l- OPrint a(i, j);
Next
) S5 ]0 I/ x+ e+ O1 [a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
4 J4 U$ a* N- c, B6 |6 Y& ]) ~Next
& k& K1 j5 I6 s8 P  c7 |
- K3 x( E+ Z" H' JFor 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！"
Exit Sub
Else
For i = k + 1 To n
6 ?* s& J5 V7 m' zl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
1 w8 V0 }, Y* g. k( D4 F# g! Va(i, j) = a(i, j) - l(i, k) * a(k, j)
; }3 i, G, _: W8 t- U) H3 g! D. `Next
Next
D = D * a(k, k)
9 v/ x9 x' j0 u! K. g, TEnd If
/ ~* Y! \2 b: X2 kNext k '消元结束
1 Q4 V( K* n- U7 W( b% y  M9 x* bIf 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！"
$ A2 g" |1 ?. m# QExit Sub
Else
D = D * a(n, n)
9 m$ x3 p2 c2 C# M5 j2 M7 J9 D% U; |End If
Print "--------------------------------"
Print "系数行列式的值是："; D
2 D6 L1 Z7 C5 Ux(n) = a(n, n + 1) / a(n, n)
8 s& B5 d* ]+ W7 C6 |3 x! M7 U3 hFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
( }% Z/ J$ u* I1 n" [; v) sm = m + a(k, j) * x(j)
Next j
" w/ `; J) w3 H& g" m* B  Q& y* Nx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
Next k '结束回代
) z( n7 O% a- X+ E
' ^9 n- {" \& j3 ?+ k  _Print "--------------------------------"
Print "方程组的解如下："
+ O4 Y4 p: c) ~
$ b+ R3 C, w8 k4 [% iFor k = 1 To n
/ ?" m. r% u$ dPrint
- ^0 r  Z7 Q. p8 X6 I7 _' cPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
8 L) U; \6 {; xPrint "其中各行Ax-b="
Print
For i = 1 To n
t = 0
3 Q! W5 ~- c& T1 @For j = 1 To n
t = t + a2(i, j) * x(j)
7 H( q9 }) t  {7 B6 HNext j
* \  W* p, m% W: i& k$ et = t - a2(i, n + 1)
# G* K8 @3 W2 Q3 e7 _4 ]Print Spc(5); "第" & i & "行："; t
" |% O! M4 Z% d; \7 FPrint
Next i
: f1 [6 D9 R: T' R
0 T' H: }4 Z7 G: _+ W4 B* zEnd 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