[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
/ u, s2 U1 R6 W9 li = 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))
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
/ F  ^# _6 }, k! C- UReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
For i = 1 To n
/ U4 O" E* k0 t# U; V1 @9 dFor j = 1 To n
+ J& ]% o! m& m2 H" Va2(i, j) = a(i, j)
( i9 D1 h* F: ~2 l( a7 MNext
Next '将a()的值全部赋给a2()
m = 0
; x7 x* N% \# o% W6 ^7 AD = 1
ReDim x(1 To n)
Print "--------------------------------"
# h6 {5 c7 U8 {Print "您输入的增广矩阵如下："
4 `$ @0 j4 B9 A' @8 A8 }3 BFor i = 1 To n
8 Z% a9 i1 c* Es = 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, " "))))
. }8 R8 s, G* o  T) _% UPrint a(i, j);
8 W' i, |7 W) H2 Z4 RNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next
* Z. C: J5 s- R, ^
3 g$ w: l' b6 B& |. sFor k = 1 To n - 1 '开始消元
) a! d* G- V- _5 U+ `2 u& {( B  b5 uIf a(k, k) = 0 Then
* _, }( M8 K6 ^. Z* pMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
  u* G: E5 [" w/ k! ?Exit Sub
8 \7 A. }0 @" e1 CElse
7 e( d# {. {# r. zFor i = k + 1 To n
  E6 Y: S% t/ f  h- F3 g3 K, [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)
Next
Next
D = D * a(k, k)
' }  a0 [8 Z# ~" I% }End If
" z. U. F* ^7 F# _( g! U2 d( H* h4 t7 YNext 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！"
% l. K0 I. ?- r4 O2 E  E: JExit Sub
Else
D = D * a(n, n)
' i1 u# e  z( U3 X* @4 jEnd If
Print "--------------------------------"
Print "系数行列式的值是："; D
% `5 B1 g' V* R; c8 Yx(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
m = m + a(k, j) * x(j)
+ r  {; v2 H7 o7 q3 H  hNext j
8 E' d9 u* \( c/ ]  A% ]1 x9 Kx(k) = (a(k, n + 1) - m) / a(k, k)
9 y6 t% y4 h3 v% fm = 0
Next k '结束回代
* I; x6 Q, H7 d0 J
& }1 K7 ~' t0 z" ~# dPrint "--------------------------------"
* U/ y& ^" v6 n* ^6 _Print "方程组的解如下："

For k = 1 To n
Print
% [( F2 u/ b+ c! M, L; yPrint "X(" & k & ") = " & x(k)
+ N+ \9 o& l+ N) v- S/ tNext k
. Y3 F0 j& w* I4 ^$ YPrint "--------------------------------"
Print "其中各行Ax-b="
2 i: u- `% F7 M, }) m/ O' z) d9 \Print
% Y' B; d* C: [: V  d- _% _; T' yFor i = 1 To n
t = 0
8 d# Z; L) N3 V) P- lFor j = 1 To n
# |) Y" Z% M( s, E* d7 y  o6 h# m: ]t = t + a2(i, j) * x(j)
Next j
! d4 M, c' l' `( S. \# Nt = t - a2(i, n + 1)
9 E9 R; T7 {/ U: b5 V9 b& ZPrint Spc(5); "第" & i & "行："; t
7 \; j3 g1 z! v; S7 E! APrint
+ j3 }% c1 E: y3 N. oNext i

End SubPrivate Sub gauss_Click() '高斯消去法
2 b1 {/ S" H/ A, v# }7 WDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
1 ?1 U) r; d! R, t2 ^7 h, T) vi = 1: j = 1
- s7 F  f2 V; |8 t& @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))
9 \, I; A! s3 D/ E! [/ |/ I7 oReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
) w2 G# N" z) d  m5 U0 VDim 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)
% h2 x' i& M! `  C- z3 R* iNext
7 ]1 e# ~9 h& e+ ^" A( h+ ONext '将a()的值全部赋给a2()
m = 0
. ?4 `' j4 q7 J4 ]( E! xD = 1
" P; f: K% X' n% o7 C& m% [7 gReDim x(1 To n)
* M8 v% C$ d% x; e9 G0 _Print "--------------------------------"
Print "您输入的增广矩阵如下："
7 S5 G6 l8 O  `  l6 nFor 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"))
- j" b  s3 w7 o/ v' [For j = 1 To n
- w( u+ O5 K' ?; F/ Ba(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
8 X6 u$ C7 p$ y0 j" Z! [Next
a(i, n + 1) = Val(s)
0 P/ N& W" K$ `- t) x1 Q, ePrint a(i, n + 1);
Print
. A9 y- v4 \# N; P0 wNext
$ o- y' f- {# f5 z( u  m" q4 N
For k = 1 To n - 1 '开始消元
/ V) v) u8 F* `$ y% {2 {# _, K+ ]7 ?If a(k, k) = 0 Then
1 p& H+ _$ M( `% d7 W% |MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
. a( T7 I  ~5 }5 ^! I4 SExit Sub
Else
( k7 Z( `/ G* M& [0 OFor i = k + 1 To n
/ |; L1 ~5 B: ^l(i, k) = a(i, k) / a(k, k)
8 s: u  f* }/ M4 u) B" M2 B6 F9 Z9 P7 mFor 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
. p8 D) o: o5 d$ HMsgBox "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
- {2 f5 N+ Z( r/ w) ^; AElse
' M: P- a" _" B/ q( Y) L/ JD = D * a(n, n)
1 U/ S1 D: `4 Q. |, gEnd If
9 E+ n* k& v- u  U6 d9 K. ~7 I0 rPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
6 _, z+ f- }7 H' YFor k = n - 1 To 1 Step -1 '开始回代
: o8 T1 V) e5 N, Y& I" b. XFor j = k + 1 To n
8 j' a7 @( C, L7 T/ F8 Rm = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
& z  V" ?& l1 v  A& }" y5 w% j, ~m = 0
7 R- a+ _8 O6 y2 r. rNext k '结束回代
" r1 G% W. T- s" L4 Q1 e+ w% h4 |
$ K! R  m9 `4 E* |0 T$ l5 r* ?Print "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
$ a+ v7 Y& w# k$ \Print
Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
0 `, z, p2 Z2 s/ x4 SPrint
* x& y* L% C( t9 h; \6 e- `For i = 1 To n
. {- p0 c7 U6 yt = 0
" K$ a: n4 D8 t( i2 {For j = 1 To n
t = t + a2(i, j) * x(j)
7 W1 r# j2 L; M  \. l5 t0 F8 WNext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
( o& i* p  h' P$ k/ S, M9 YPrint
# A$ ?0 ?2 P! S  R3 hNext i
+ Z& F1 P5 ~  O1 @, X# ?/ b
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