[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
  a; T1 c! i5 q6 N, z7 F6 pDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
6 R4 x' C% S6 }  y2 I/ q6 qi = 1: j = 1
5 Q+ I$ @+ S, ~; j( ~6 Hn = 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
- G( c6 x4 e' G& q8 GReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
8 o+ K  j& N( g9 ~* \  SFor i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
- q  u' F0 x" n) w1 Q3 wNext '将a()的值全部赋给a2()
4 Q) H1 d8 w+ _6 W7 ]" Lm = 0
* W% Y! w7 E9 g. b) FD = 1
ReDim x(1 To n)
Print "--------------------------------"
- [$ L. Q6 e1 y8 I% s, gPrint "您输入的增广矩阵如下："
: \0 n. `5 `4 h& NFor i = 1 To n
* W" s  |  |, e3 y/ U& j" L* ns = 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
' S% L9 ^- ^6 v6 za(i, j) = Val(Left(s, InStr(s, " ")))
7 X; f# _$ P! T+ n% Z, is = Trim(Right(s, (Len(s) - InStr(s, " "))))
6 A" w& [; Q* g; v, ^2 }( Q1 E+ C: @4 zPrint a(i, j);
Next
2 \$ ]0 v: {- {1 d7 P2 D; ya(i, n + 1) = Val(s)
. E  y! L7 n1 S- L& PPrint a(i, n + 1);
Print
Next
. t6 ?4 o% d/ u3 X* J% e
/ j0 A, v/ p+ D5 KFor k = 1 To n - 1 '开始消元
& e5 j& [6 m8 p- u9 L- `. NIf 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
; O3 A" m- s9 b7 j% M: Q) `For i = k + 1 To n
4 q/ a' H1 _6 v1 L/ k5 z; p4 ll(i, k) = a(i, k) / a(k, k)
  H, w2 ~& D1 V' ^9 C) Y# lFor 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
6 D6 p7 W+ ]! V# qIf a(n, n) = 0 Then
" V6 I) q2 L; ?5 V! bMsgBox "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
# L1 O% b, v- o: DD = D * a(n, n)
& H, N; p- |) cEnd If
Print "--------------------------------"
2 |) O+ B0 e0 T/ J1 XPrint "系数行列式的值是："; D
2 C) _; L1 @8 a$ v# j: a% Dx(n) = a(n, n + 1) / a(n, n)
) W2 W, b6 Z& \3 ^9 N6 x+ e1 ]* wFor k = n - 1 To 1 Step -1 '开始回代
$ |8 w/ P8 }: M% F; \5 a- {For j = k + 1 To n
# |: M$ w3 @0 R5 Rm = m + a(k, j) * x(j)
! o% A: \% F( HNext j
8 Q7 a+ T0 J( u' d% `6 O, |x(k) = (a(k, n + 1) - m) / a(k, k)
2 a& u* G, G' ^4 K' M  q% r% Q' y5 u5 ^m = 0
Next k '结束回代

Print "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
4 V; Q9 q1 K1 {+ y8 ?& q" GPrint
Print "X(" & k & ") = " & x(k)
2 c/ a" H2 X4 T& g, W& ^Next k
# A* l6 o5 b$ y7 s- MPrint "--------------------------------"
) l$ E' b9 a/ m5 q( G; YPrint "其中各行Ax-b="
: M! W3 v4 s9 c/ P8 ^# s- ePrint
. [: X( `+ Q% D- x. b0 F) _For i = 1 To n
t = 0
For 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
Print
Next i
% I6 L6 O" t$ B2 w  N1 T2 t
7 |1 L3 d( g% J& N4 h' bEnd 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
# M8 r* M9 g% u0 Ni = 1: j = 1
/ q/ F, i0 c" g5 b7 q& R' W9 k$ @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))
7 r; r! s( f+ l; ]3 O& wReDim Preserve a(1 To n, 1 To n + 1)
# M  R/ l8 z7 y& r- WReDim 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()
- g% ~$ I  v0 D6 x0 I- m3 `For i = 1 To n
  f- u5 m% t8 E$ ~. bFor j = 1 To n
( |4 _, ^2 w! d( ]' z6 Fa2(i, j) = a(i, j)
- y4 p/ U+ u' r! cNext
9 A2 |( o9 s; O1 ?- s9 q( b$ x( bNext '将a()的值全部赋给a2()
m = 0
. q' u% g  k( }; U: q. ^: ?/ ^+ MD = 1
& ]1 C: p- d# LReDim x(1 To n)
" a( k/ v1 }( J6 E6 gPrint "--------------------------------"
, n8 T$ }0 D( D& e$ |0 GPrint "您输入的增广矩阵如下："
7 |4 Y; x$ w) e. ]" E8 ~  l  f5 tFor i = 1 To n
7 H- g. ^0 B6 R5 }( L  Os = 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"))
0 M3 w2 V3 s4 f% n1 hFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
/ ~% y, n  [$ R- [8 hs = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
, C% }& A9 Y7 N3 Qa(i, n + 1) = Val(s)
8 j* P8 G6 B# p6 I3 J: wPrint a(i, n + 1);
! i8 z8 A3 M2 E! c! z8 a% lPrint
2 y' B% f$ R2 V4 @9 vNext
% ^% ~6 g$ K. H+ z8 W8 o
% X! A, w. ]3 v+ p/ W- tFor k = 1 To n - 1 '开始消元
, V# q9 z, X+ N* p: L5 ?8 _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
( M# [4 r, X( ^! Y+ vElse
For i = k + 1 To n
% P- B$ Z& y% D! V5 ll(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)
Next
$ B( }4 m' C2 j' u( XNext
D = D * a(k, k)
! e& H  Q* ~4 e8 h  `% JEnd If
3 B# P2 Q1 w0 _+ BNext k '消元结束
4 }7 W- N$ W9 G, r7 r0 |/ p% HIf 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
Print "--------------------------------"
0 c" @' M3 V: ?0 C% m9 A5 P6 `# EPrint "系数行列式的值是："; D
7 ], _3 M7 o; |1 l3 p: Px(n) = a(n, n + 1) / a(n, n)
! X. t' q$ ^; b+ [" @For k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
; }2 E) ~& N% r/ M  i( d* `2 `m = m + a(k, j) * x(j)
Next j
3 F9 N0 k8 A) J( e/ W2 Jx(k) = (a(k, n + 1) - m) / a(k, k)
$ G4 o- H$ A; T; ]* Rm = 0
# Z+ r1 v# x& z& fNext k '结束回代
* T: c% P' |5 y. A
8 f! a3 h% e( W# n, kPrint "--------------------------------"
6 ]& q' m; |8 N( ^% _) LPrint "方程组的解如下："
$ r4 M- d5 R3 p* B, {' X; Y6 g' T
For k = 1 To n
Print
# N& J6 W& g% PPrint "X(" & k & ") = " & x(k)
Next k
7 I" I4 Z$ \) O# p: l4 GPrint "--------------------------------"
Print "其中各行Ax-b="
1 g* S2 V* |7 pPrint
For i = 1 To n
t = 0
7 s: t4 I: l8 s0 {( W) {6 n# iFor j = 1 To n
t = t + a2(i, j) * x(j)
4 z- ]% v* ?/ [2 [) Q0 sNext j
+ K1 q$ P4 F' F3 ~8 h/ O  W: I5 w' j: h' It = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
8 S* l$ F( Q$ [; l  y& f; F8 oNext i
4 h$ o2 W7 H0 `" c
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