[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
8 V. X& y: M' _8 {Dim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
9 }8 [, f$ m' \: f6 y. P, z, Ji = 1: j = 1
$ [4 l6 u2 \6 S* H' M+ An = 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)
, O1 |2 x4 J2 {6 |: uReDim 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
5 W# ~+ f  y# X/ ~. g4 BReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
! Q; w  f( i! q" TFor i = 1 To n
0 J6 V: S0 A% z* p+ w* \6 pFor j = 1 To n
5 g5 e- K7 M, A; c4 g5 |3 \* Ga2(i, j) = a(i, j)
Next
  q4 w% a- \/ V6 f  G+ |  t5 VNext '将a()的值全部赋给a2()
# S$ t+ Q. S( ?* j. x  @# ?9 R9 qm = 0
D = 1
ReDim x(1 To n)
+ o; q& i* \" WPrint "--------------------------------"
# Q' J5 M7 \8 G8 BPrint "您输入的增广矩阵如下："
6 |: v; b" y" n6 LFor 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"))
! q+ ]4 e- |3 Z2 e  L5 M: |- EFor j = 1 To n
3 C/ y& C( ]6 ?$ }6 i0 Oa(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
( P( _3 u& X5 M3 N! `0 g; I3 b. cPrint a(i, j);
Next
0 v7 S" ?; h: G0 I3 l: j3 Z  ~a(i, n + 1) = Val(s)
Print a(i, n + 1);
. @# E0 c' }" X  m1 b, P5 f! UPrint
Next
  ~2 ]( X) a) @6 ]( ?3 P3 T
2 M4 [$ H9 J/ M% H. k. |For k = 1 To n - 1 '开始消元
* \2 ^8 y. g" v; M0 HIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
# k% }$ r% r6 p; `( h1 MExit Sub
" v- f. K9 {& Q. T/ E! o# lElse
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
+ o# ~% n: {6 L7 O+ `, e, K$ FFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
- T) r, s( H3 Q8 _" A( BNext
/ I' X4 }" M. t2 s" w7 ?) ]! L' wNext
- A6 C9 J- n2 f2 \D = D * a(k, k)
End If
# J. d3 [8 k2 u  ^0 N' RNext 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！"
' P9 T! u  v# p7 @1 ^& @: d! [+ V$ oExit Sub
Else
D = D * a(n, n)
4 n' D8 P- y6 J) n% o, V% HEnd If
7 H  f/ b8 a$ o: z! RPrint "--------------------------------"
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
4 n9 I+ @4 }. _/ i* B4 I4 A- ]" dm = m + a(k, j) * x(j)
3 f- m4 P) x) M. D& @/ |  Q7 [Next j
+ e$ ^+ T" ?! Q; Y* X4 x' |x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
) s! a6 e" E! m& @1 q$ tNext k '结束回代

' j& D" y/ x0 v$ s) B* ^Print "--------------------------------"
, Z7 |  e; ~. X3 dPrint "方程组的解如下："
5 l) F# M3 q8 y* E
For k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
) q% G2 [( p3 {3 [& DPrint "其中各行Ax-b="
5 S  I. {9 }% T9 GPrint
9 V& `! c. b- i% l% iFor i = 1 To n
) Q. T/ C, z; P  M. p+ Jt = 0
: v4 N' i8 Z8 D# M- n! Z. a" kFor j = 1 To n
- B& }! f3 g. {, ft = t + a2(i, j) * x(j)
9 r- F+ l3 t$ @* l% o% B" c% t0 zNext j
0 s6 I  `. n2 B) y* T1 }t = t - a2(i, n + 1)
3 Z$ X# \8 L  B. APrint Spc(5); "第" & i & "行："; t
) \/ y( W/ a2 D9 m! mPrint
Next i

0 v3 a' H! L5 M, l& x0 ^End SubPrivate Sub gauss_Click() '高斯消去法
/ v* O3 W, d  b2 `1 S9 C' vDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 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)
5 |" }0 v& n9 E( i7 a* mDim 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)
- a3 l3 B  M3 N1 h) j  V- aNext
Next '将a()的值全部赋给a2()
5 Z* `  r: e) B" U# Bm = 0
D = 1
  q! s' `9 s6 `( _5 D" v- HReDim x(1 To n)
6 F0 x4 d* p* _+ d/ H' wPrint "--------------------------------"
: u: n$ `" Z& g+ e3 YPrint "您输入的增广矩阵如下："
For i = 1 To n
9 b( N4 @$ C5 }9 M3 q* \1 a2 Y/ Bs = 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"))
! T+ I4 @, {3 n" ^# X: E- zFor j = 1 To n
$ f* ^5 M7 u& o. V/ v" f- M+ Ja(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
2 `. \3 @# L7 d6 f1 Da(i, n + 1) = Val(s)
8 }+ n* p+ b! n2 ?* GPrint a(i, n + 1);
3 `  K+ {  g$ Q* G# n4 pPrint
9 H/ @/ p5 I$ y6 h% \6 LNext

. b6 A1 h) @; H% N/ ^' ZFor 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
Else
For i = k + 1 To n
2 J1 ~+ \$ i, ]. J6 h( M; K9 Il(i, k) = a(i, k) / a(k, k)
+ |/ e. {4 p8 @! Q7 eFor j = k + 1 To n + 1
" Z- L5 Q( Q$ ]8 i4 ma(i, j) = a(i, j) - l(i, k) * a(k, j)
7 ?) [- @! Y' d% H6 Z: Q5 I+ eNext
Next
D = D * a(k, k)
5 q! f0 k, a+ lEnd If
, Q5 ]1 ~( S' W# u7 `- 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！"
- X9 v9 _& B$ ^- ^+ s$ nExit Sub
- ?! F2 H4 Q& y' t( q) }- l0 WElse
D = D * a(n, n)
' y( E. c- F  Z+ C+ L$ G8 gEnd If
Print "--------------------------------"
Print "系数行列式的值是："; D
9 n7 X- M  y- Kx(n) = a(n, n + 1) / a(n, n)
' R0 R2 h4 M" H/ x% I& jFor k = n - 1 To 1 Step -1 '开始回代
1 c; l+ M1 u/ R% i( [" kFor j = k + 1 To n
& L4 r( \0 `" D; Um = m + a(k, j) * x(j)
Next j
) ]4 r; F; ?. f7 f+ Px(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
/ D6 A- {5 ^6 z: v& q8 TNext k '结束回代

1 f( o/ s: U' {& Q0 X  B  tPrint "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
Print
$ o8 _" N" U1 M" y$ zPrint "X(" & k & ") = " & x(k)
6 A; S8 y( `5 q- ^2 n% oNext k
* w$ w1 t/ N1 }8 b" p/ f% tPrint "--------------------------------"
9 ^, z0 l; D) W" L: kPrint "其中各行Ax-b="
2 ~7 A/ d* k  {; W, L5 U# bPrint
7 }; Q: W9 _1 J) J4 M5 X9 W. lFor i = 1 To n
t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
8 @) ^& b7 ~  i+ S6 it = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
0 \# e* l( Z' nNext i

& J" q+ E! e! D; [3 b; O% X% zEnd 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