[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
3 Z2 K( l" e- o! In = 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))
" N: N) v; P% J% P; QReDim 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
! z: p9 E$ x* d6 q7 {7 RReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
For i = 1 To n
$ Z6 d8 Z4 s8 [/ B. K6 E, pFor j = 1 To n
$ J7 C$ K: S) \a2(i, j) = a(i, j)
Next
3 W5 p" M; z8 g5 k% yNext '将a()的值全部赋给a2()
m = 0
- e6 G' j0 `( X: }( X3 K8 ^D = 1
ReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
' {4 s7 v4 V5 v5 L$ TFor 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, " ")))
/ e, v$ D: O5 R, x  o1 Js = Trim(Right(s, (Len(s) - InStr(s, " "))))
+ x9 j% d1 @4 i, ?8 {9 t- cPrint a(i, j);
0 ^8 m6 V  ]1 C% ~Next
a(i, n + 1) = Val(s)
Print a(i, n + 1);
/ `( J0 @8 S! v6 c" v$ [Print
Next

0 D: a- s# F$ @4 wFor k = 1 To n - 1 '开始消元
5 t4 r4 Q! p, K/ u' {# eIf a(k, k) = 0 Then
+ c9 C0 @  l$ v% @, r/ e- TMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
7 O2 u: E/ z; f4 I  x# F& WExit Sub
# K' p$ F% V$ _/ A, v( K8 {/ x: sElse
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)
) z# p  ^2 u: X6 ZNext
2 ~6 K% _/ r9 R, S- [& \9 y0 dNext
D = D * a(k, k)
, X7 s2 x6 H: L9 S' K1 w) f4 ?' gEnd If
9 R, c: u* z$ K- q9 NNext k '消元结束
) V  p3 {! V( {If a(n, n) = 0 Then
3 ]2 Z5 R- [) D% `" T2 v9 z. O8 dMsgBox "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！"
7 Y8 \% \% Y  J; l6 t) YExit Sub
Else
0 f# U6 m5 X% ^& Q' ^9 A$ [3 r2 {D = D * a(n, n)
' z+ j4 ~+ @# W9 EEnd If
$ N& w' F% Z1 ?! p0 gPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
$ I3 a5 H9 ]! AFor j = k + 1 To n
m = m + a(k, j) * x(j)
' f( ?" N& r& b# B- tNext j
5 ?# `' U+ X4 d" d2 M4 `3 vx(k) = (a(k, n + 1) - m) / a(k, k)
6 y7 w8 ?6 ?9 \+ }" tm = 0
4 d) V7 D) p4 v* z8 I4 A( ^Next k '结束回代

; @' Q3 g* I- r  t4 aPrint "--------------------------------"
Print "方程组的解如下："

7 ^0 s3 ?+ s! RFor k = 1 To n
* T6 i& O+ f0 KPrint
/ |# r( O: p. _/ r$ @  W! E7 R9 U2 D. ~* bPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
' h* f9 Y/ x0 G1 p2 d" Y7 HPrint
For i = 1 To n
( y1 o: ^  S9 Pt = 0
For j = 1 To n
: J3 C7 z# K+ u$ O( f8 M: {t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
1 L) D( l& m  R" ^) lPrint Spc(5); "第" & i & "行："; t
4 n4 `, A+ B0 \" u/ pPrint
Next i
# c  U" n, g, A
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
/ J% V% ~3 V" ^; x- r# f" @$ Ni = 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))
) G/ {$ M; Z6 N! H! b+ t/ m( E6 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
6 h: y" ?! m1 y2 qReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
- r' z; W9 O/ P9 N/ G0 T  n% z& NFor i = 1 To n
For j = 1 To n
/ B$ E+ M6 o" N2 b6 l( Qa2(i, j) = a(i, j)
9 p$ F; ~: Q" z' x) L1 |* _; KNext
Next '将a()的值全部赋给a2()
. z+ A7 C: i7 I1 R3 Jm = 0
D = 1
$ V. Y* _* I( w$ A. x9 D6 t3 T- uReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
: \# C, ^9 L& y& D+ gFor i = 1 To n
& J. F' R/ Y$ A2 O1 H- P) Ps = 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, " ")))
$ B; D) p8 X/ B/ Us = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next
4 V" x: y+ A! h6 @) @
For k = 1 To n - 1 '开始消元
, |5 h) s. [7 A! gIf a(k, k) = 0 Then
& s+ ]; H) A9 qMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
) s) [% m% y) mExit Sub
Else
For i = k + 1 To n
+ k( G. f- a$ l# R- I' Ul(i, k) = a(i, k) / a(k, k)
# {2 h( [2 x# d0 {For j = k + 1 To n + 1
( [, R7 f# p; C8 Pa(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
$ k3 W1 |6 I. p. |' n9 s9 fNext
. F5 D. D7 {: C0 U1 CD = D * a(k, k)
End If
Next k '消元结束
, ]% J' x! e* z9 ^9 Z7 AIf 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
( {% ^, R4 y) e: m3 q7 JD = D * a(n, n)
% i5 k" a/ ~4 yEnd If
Print "--------------------------------"
Print "系数行列式的值是："; D
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 H0 `6 c3 B* f9 T4 u% {# km = m + a(k, j) * x(j)
0 |2 `, }6 h* c  I( kNext j
x(k) = (a(k, n + 1) - m) / a(k, k)
, p( J% {* K6 {; r# Y6 i* Zm = 0
Next k '结束回代

Print "--------------------------------"
8 R4 o5 B/ {5 d( b  u5 Z/ yPrint "方程组的解如下："

- k5 Q2 E) h8 `# {For k = 1 To n
Print
% E: D( {. s6 q1 M/ ]) Y0 }Print "X(" & k & ") = " & x(k)
4 g, @' f9 N. S1 L4 ~% Z9 sNext k
# E# d. e. w2 J/ pPrint "--------------------------------"
  S  j3 i# r7 J1 nPrint "其中各行Ax-b="
' L. O/ C. N; tPrint
$ [9 O/ h6 V$ B' d' K. T! C. JFor i = 1 To n
% @2 ]# j2 [$ J/ x5 f" _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
5 y2 `3 P" o1 y( @1 Z0 IPrint
8 Q; @/ p' N1 \7 A, w/ ~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