[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
5 ~( J1 D# S! r" g; CDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
5 i2 ~0 y0 |4 s$ @9 G) p2 [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
ReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
. u, i! v: x4 r! [( {. j: bFor i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
9 j9 x: T8 u8 S4 o3 Em = 0
5 l2 j  |, v) N( s0 GD = 1
4 ~3 L  O# A( C+ kReDim x(1 To n)
/ p) @9 u6 I& M" W+ G! H7 l+ @Print "--------------------------------"
Print "您输入的增广矩阵如下："
For i = 1 To n
- C  @  p" U4 A4 [$ ]9 `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  Q. B  u( Y: r# ia(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
& k% D' p6 b8 X" uNext
2 L- N: t4 }. Q3 ]+ Ja(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
# R8 U* G. m( U/ B1 A4 MNext

; z9 X; K$ }5 E' W; S. DFor k = 1 To n - 1 '开始消元
  G& z8 Y- k9 c+ j2 R/ o* i# {* XIf a(k, k) = 0 Then
5 Y' O% @/ W, e9 Y+ ?# f. OMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
Exit Sub
1 L9 Q0 |" y8 N* I/ F3 wElse
For i = k + 1 To n
% s: a- Q; {4 ?) ~  @2 _2 Zl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
, a. @! L8 H9 A- |: M4 X. Ka(i, j) = a(i, j) - l(i, k) * a(k, j)
6 J& v# a. B1 {! L0 `# D, DNext
Next
2 o2 Y" X2 J4 M6 D  J+ H' Y0 RD = D * a(k, k)
% J* o( S& w3 [0 J/ E% F" p5 b; ZEnd If
) T7 [& m6 D# UNext k '消元结束
2 e5 b# R) [, k5 Z+ G/ ~7 xIf 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
8 L. H* ?& {* S7 x, ^* X4 {Else
; d+ L* ]( S3 ^% BD = D * a(n, n)
End If
Print "--------------------------------"
# s7 D1 X6 g" a" @) fPrint "系数行列式的值是："; D
; {7 B( x2 m& N6 c, P0 h/ Y4 ?& [x(n) = a(n, n + 1) / a(n, n)
: D5 T/ y( l. M& LFor k = n - 1 To 1 Step -1 '开始回代
: a& C9 a+ f4 z: \8 H2 l% ~For j = k + 1 To n
5 ]/ |$ i3 c0 Xm = m + a(k, j) * x(j)
2 ~! `1 T& n" qNext j
1 }$ D% J* ?, s  Y7 tx(k) = (a(k, n + 1) - m) / a(k, k)
& u) ?1 F) c% Q. Y$ E* ym = 0
Next k '结束回代

Print "--------------------------------"
* ^3 s2 |: l! R8 O1 H! \7 yPrint "方程组的解如下："

! k3 R8 F) z! j8 C: IFor k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
+ d3 ~7 h+ Z2 @* a  i; @Next k
Print "--------------------------------"
; k- @+ ~$ o" UPrint "其中各行Ax-b="
. q: E1 f; [2 Q) {- [7 {4 `3 K. MPrint
) y6 M* x/ Y8 D# D0 QFor i = 1 To n
t = 0
" M7 c* E/ B. |* K, _8 RFor j = 1 To n
4 M! |( y' A/ l1 |- @8 Z& Ht = t + a2(i, j) * x(j)
; m1 _, m! H7 r& c7 P" T0 jNext j
1 F' l, p# e1 z6 jt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
7 \: ^3 i# P# iPrint
4 Z# r( Q3 v9 P0 l, @& Y. aNext i
9 ^2 r- Q+ f2 y3 P0 {- _
End SubPrivate Sub gauss_Click() '高斯消去法
" p: H5 Y6 v: p8 w  V$ z$ k5 bDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
7 K& }0 j# D/ t3 h/ A" Z9 Wi = 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
9 |/ G$ O2 \, n) LReDim 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
6 y5 m0 l7 q5 g" pa2(i, j) = a(i, j)
9 l( X" F9 I8 f8 k8 RNext
Next '将a()的值全部赋给a2()
- Q8 V9 Z; \: T0 D3 n& d. om = 0
! H5 E- J( G  u3 mD = 1
: Q8 x; Z$ }; h4 ]3 LReDim x(1 To n)
Print "--------------------------------"
( d- d5 e8 T" p) C5 \$ b. ZPrint "您输入的增广矩阵如下："
. p& u+ a3 x+ `. w, |For i = 1 To n
7 _+ s' J$ F; |; ms = 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"))
' H# v. w: |+ }3 |5 C" N3 V6 i0 QFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
& K1 i$ m: \( i  n9 `' Rs = Trim(Right(s, (Len(s) - InStr(s, " "))))
4 B9 j  m" |$ ~: _% z$ U; }0 sPrint a(i, j);
! Y& Y8 i) s4 @5 XNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
1 Z" X/ b* p( R5 G+ gPrint
Next
  h2 U4 h2 j& v. D1 }  g( ]; S
! k2 l4 \' t# w/ r2 }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！"
Exit Sub
- ^$ ?1 Q- O2 U9 Q! SElse
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
0 W1 `$ X2 `* k& nFor j = k + 1 To n + 1
2 {4 r0 K+ o: [7 ba(i, j) = a(i, j) - l(i, k) * a(k, j)
% p7 d7 g' Q$ f  ?8 _, b9 vNext
/ ?3 Z% P9 Z$ \6 _8 \" I' TNext
/ A8 }4 M6 X  hD = D * a(k, k)
End If
0 k4 f4 v$ G; ANext 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！"
. x& v; H# g5 }( ?Exit Sub
7 [  _" v* o4 k, b# m: b1 YElse
2 ^' `9 S/ z+ F8 J; bD = D * a(n, n)
7 h9 _: e% D" z& S! G% r2 ]End If
+ ^# P, Q/ R, \& E* N3 ?( V, X( l  t' \Print "--------------------------------"
Print "系数行列式的值是："; D
9 l. r: _' Q0 N- W4 Y% Xx(n) = a(n, n + 1) / a(n, n)
  S% q2 M5 I$ C1 xFor k = n - 1 To 1 Step -1 '开始回代
5 q/ F, ^9 o6 L/ YFor j = k + 1 To n
m = m + a(k, j) * x(j)
Next j
. V( B& w: v" ^4 Yx(k) = (a(k, n + 1) - m) / a(k, k)
% X% G/ j4 M0 [0 y  v, Mm = 0
7 M3 q* N. T, U: T- S+ z. t6 V; }* RNext k '结束回代

$ w1 F+ Z, T7 D8 S6 vPrint "--------------------------------"
Print "方程组的解如下："
% |6 s! E9 `% x% t
For k = 1 To n
; S3 G5 }3 s& ^6 o: ZPrint
Print "X(" & k & ") = " & x(k)
Next k
% r- Y- L3 A+ z! uPrint "--------------------------------"
& N9 q3 Z  X) d3 o$ w6 vPrint "其中各行Ax-b="
Print
# A1 B! [+ Y0 o- @' tFor i = 1 To n
# u  f8 p. S7 P  m' ~/ Ut = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
! s0 n: h9 g  @- g# |t = t - a2(i, n + 1)
- z& m4 u7 m& p9 }6 `0 X- q  HPrint Spc(5); "第" & i & "行："; t
Print
Next i
8 G% y, \( E. P  p8 e
1 w. M. ]5 L5 ~: I3 t, `$ }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