[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
' S/ B( A2 Q( R+ d! TDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
% o; _0 n) B* b* p% ]i = 1: j = 1
* N, N* j$ J0 M3 jn = 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))
+ _" a2 ?+ c9 F3 U$ JReDim Preserve a(1 To n, 1 To n + 1)
0 }3 |3 C+ ~5 g/ N; D& DReDim 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
# x& m4 c* i7 I8 l0 K9 O' GFor j = 1 To n
a2(i, j) = a(i, j)
% S% \7 j/ e; K4 d5 T0 aNext
Next '将a()的值全部赋给a2()
) D# v) j8 C6 s, p6 g7 c) Gm = 0
D = 1
# [4 ~* N( D' n8 k9 M3 Y. r' h5 yReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
4 g8 K: V6 c3 r- Y: x  d' EFor 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"))
% u9 l- q) k! b9 `% b! DFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
8 J0 H1 R) X# Q) k) Us = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
# z- N/ O) p9 K  J* y3 ], tNext
a(i, n + 1) = Val(s)
% R% j7 [6 P, x0 ]" Y3 P7 J# f3 ^Print a(i, n + 1);
) n; a- K& _! ~9 h) IPrint
Next
* N  N; ?2 ?8 _; b# I9 Z
9 s( ?, [3 [. CFor k = 1 To n - 1 '开始消元
& ~& n; h0 T; \3 x0 H- lIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
6 [- i5 C8 ~. X$ z  m( QExit Sub
" J! b5 n8 |, [- i3 J" Q, rElse
* A% M% t0 ^& r. h8 o% HFor 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)
( P  v  c+ E  ?) rNext
Next
5 ?9 d0 F, U' mD = D * a(k, k)
End If
! A* G: _+ H* h( Q. u1 B& {+ xNext k '消元结束
4 J2 O6 u# y" _6 |! TIf a(n, n) = 0 Then
4 }, j0 w$ N# B& C' J2 k  u: 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
, _0 ~. \: H) p, H( o9 ~. UElse
1 Q) w: }8 {* @* Y0 h' B2 ^D = D * a(n, n)
' i) R& y1 Z6 h8 v. ~6 j8 U! ^, YEnd If
5 A0 R: H5 x/ V" BPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
9 S6 R) i/ E  KFor k = n - 1 To 1 Step -1 '开始回代
, U& Z' t- }" m9 J- RFor j = k + 1 To n
m = m + a(k, j) * x(j)
* i. d5 u# I% Q) vNext j
; P% |$ c, {6 g* t) M; tx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
Next k '结束回代

Print "--------------------------------"
Print "方程组的解如下："
$ H" E0 h& p8 n' ?, `
For k = 1 To n
% v8 I$ z: h$ G7 _+ s8 PPrint
3 e$ i: p1 @  W0 L! GPrint "X(" & k & ") = " & x(k)
* N! r% n7 u& YNext k
2 \1 ?, h" `4 KPrint "--------------------------------"
Print "其中各行Ax-b="
Print
For i = 1 To n
2 K5 {+ A7 b4 P  A4 i5 P9 o4 i4 it = 0
  b" R- Q9 V5 w; YFor j = 1 To n
; ~0 l9 u( Y9 J8 c: ]t = t + a2(i, j) * x(j)
  Y6 |: K' t6 l" C- I( P4 SNext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
8 R* M- x7 K& Q* QNext i
( @/ G8 y4 E& r% B! 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
i = 1: j = 1
4 D) J7 m6 h6 ]5 U! g' G- _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)
( t0 Q0 ^: \. L& D! lDim 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()
) s' h4 R9 L- G, t; j5 gFor i = 1 To n
For j = 1 To n
( ^" ]. w+ P/ R5 B$ y* `" v0 w: }a2(i, j) = a(i, j)
Next
6 g8 E5 t  o: i! Q, }. CNext '将a()的值全部赋给a2()
. l0 a8 {7 S9 a- Hm = 0
D = 1
ReDim x(1 To n)
% Q6 R; |8 m7 C7 M7 J- |( j% A1 \  A. APrint "--------------------------------"
  k9 v  X- L# ~6 A' g6 W" F9 aPrint "您输入的增广矩阵如下："
. J/ {- n9 ?$ x% [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, " ")))
! x! e% U- Z# `  j. Y* \( Is = Trim(Right(s, (Len(s) - InStr(s, " "))))
2 e2 Y, N: A! C3 EPrint a(i, j);
Next
# o8 L$ r3 q) ]+ ha(i, n + 1) = Val(s)
Print a(i, n + 1);
  C+ L3 C, f; ]' ]  ZPrint
( i! }% I) Y  V9 q! L" G8 t# mNext

For k = 1 To n - 1 '开始消元
- q# c, |5 x5 O/ zIf a(k, k) = 0 Then
6 ^7 e# P2 t; P, T$ Z# k+ FMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
3 d1 A/ n3 ]2 Q& B4 v. aExit Sub
' J' b* C: {8 y; w5 m$ f2 j5 RElse
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
0 @0 O. Y" {, ]a(i, j) = a(i, j) - l(i, k) * a(k, j)
/ P$ D. X1 [/ C6 S, s! _Next
Next
D = D * a(k, k)
& V! ]. P" f8 @8 sEnd If
. g- A, O+ @: N2 q0 MNext k '消元结束
1 A( @7 X7 @9 f1 i$ jIf 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！"
2 W+ r% w, P0 G0 p6 kExit Sub
Else
3 z4 \! T" o* G8 X! LD = D * a(n, n)
End If
Print "--------------------------------"
; Y' {( D' j7 v# [, h# f! I5 {Print "系数行列式的值是："; D
8 X8 @$ t! v6 T0 x$ @% Bx(n) = a(n, n + 1) / a(n, n)
2 a( y( i% I* @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)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
* A: v" \5 k- z, @& V9 L& [m = 0
) ]) H- _( z2 g) w" Q" h! q1 RNext k '结束回代

2 y% y& o6 i3 wPrint "--------------------------------"
3 t: s: \/ C: ~" ?( E6 Y. UPrint "方程组的解如下："

2 l6 w+ u" f5 t0 e) {. z0 J9 eFor k = 1 To n
Print
; R- r; Y' G, x: m7 rPrint "X(" & k & ") = " & x(k)
Next k
, _3 V" g, c2 KPrint "--------------------------------"
8 z" I' m  E/ b3 [( B) b7 APrint "其中各行Ax-b="
Print
For i = 1 To n
t = 0
For j = 1 To n
! ~" |  t4 o+ }3 d$ _7 w4 \t = t + a2(i, j) * x(j)
: I6 R2 ]" |& V1 R+ ZNext j
. G$ ?' l/ n- n2 S  V% U5 Qt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
: H% E2 R! U* t% R8 @Print
Next i
4 V: O7 t4 S$ g
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