[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
# T6 W9 V, p) T  Y& s. W0 aDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
- i2 S+ L) @# O8 m0 P. hi = 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))
% c! s& K0 p/ j& ?ReDim Preserve a(1 To n, 1 To n + 1)
6 }1 q7 v  v; h) {. ~& H$ I+ oReDim 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()
/ o6 g! P( W0 e, E* v, w7 JFor i = 1 To n
7 d+ T) ]' H7 ?) R7 ?" RFor j = 1 To n
a2(i, j) = a(i, j)
$ k) {) Q( l( o# J0 E/ B7 vNext
. _3 g, Q* N6 M5 F# xNext '将a()的值全部赋给a2()
! w9 [. Z( r* g" |7 `4 Gm = 0
D = 1
ReDim x(1 To n)
Print "--------------------------------"
5 `2 z0 R/ ^, a3 J. |6 PPrint "您输入的增广矩阵如下："
. \; A4 H) L# Q& ]0 eFor i = 1 To n
  d, e, U- O- w5 I  F6 \# I& _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, " ")))
  ^& A' A5 n: O( os = Trim(Right(s, (Len(s) - InStr(s, " "))))
8 I( p# v5 N$ [& yPrint a(i, j);
# r/ ]5 |0 Q0 M2 eNext
a(i, n + 1) = Val(s)
9 j4 D% m' ~0 ZPrint a(i, n + 1);
1 s. s( K3 m& y9 O; |3 A6 y! APrint
Next
4 w/ p( {/ G. s  T; Z
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
3 I  q3 T2 p; U! Z$ E1 A& {- c; 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)
% p+ Z1 v: \  \/ d! UNext
1 T; x8 U( z' w2 y: w( JNext
1 f2 j$ t" q2 v4 f1 z- b& y& [D = D * a(k, k)
1 E, V4 Q8 ]9 I# J& H$ Y2 N: bEnd If
+ W" E% E7 Z+ tNext k '消元结束
8 C; x- N" H& ^If a(n, n) = 0 Then
7 u  c0 W6 C7 c- v* MMsgBox "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！"
6 J& S( g  _& x/ C/ j1 dExit Sub
Else
% {5 m! k) `0 y1 L9 b; X, ^D = D * a(n, n)
# D. T2 T# t- c( \% jEnd If
9 s! x* a; t  m2 w% I& D* uPrint "--------------------------------"
Print "系数行列式的值是："; D
) l1 B) X% h! g, E" _: f. fx(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
" c+ g& X1 `$ J# d2 om = m + a(k, j) * x(j)
% L$ I. X) _$ E. o$ MNext j
1 x+ p% I  ^% d- u& k3 ^% y1 Mx(k) = (a(k, n + 1) - m) / a(k, k)
4 A. _# N5 G' H/ U# {1 P( ~. n6 L+ Sm = 0
Next k '结束回代

8 Z5 s: C$ \9 G8 ~  _Print "--------------------------------"
! ~5 a! S% x+ YPrint "方程组的解如下："

For k = 1 To n
+ |& t- G0 h; M* r/ x* w* _" O! ?0 fPrint
* X2 Y9 J4 t  l9 ^, d" kPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
Print
6 G5 O4 T, p0 f6 }3 V, ^! yFor i = 1 To n
) o0 l% R: J' c) [/ e; H4 u* T3 a/ o# _t = 0
( k6 B! n) `. _# AFor j = 1 To n
4 h6 s8 G+ U+ `$ [, w* y0 P7 w1 Vt = t + a2(i, j) * x(j)
Next j
) M, ^4 \  d$ i4 |7 [4 U- It = t - a2(i, n + 1)
# ?3 n6 ]9 q6 PPrint Spc(5); "第" & i & "行："; t
+ Y3 M' f, N8 X# |) K, nPrint
Next i

' M- ~3 v5 m4 F6 m8 G. }End SubPrivate Sub gauss_Click() '高斯消去法
$ t  j& @5 @+ rDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
) k! ]( g# r+ e3 vi = 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))
# Z% m% W% b) [: R1 XReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
. p1 j5 L/ W# F9 v1 @Dim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
* `, {# J9 J, Y9 W' r' k9 xReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
9 ?6 `: x+ d3 ZFor 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()
m = 0
D = 1
5 l; S7 R, Q/ P, LReDim x(1 To n)
  C9 `0 S) x8 u# d+ qPrint "--------------------------------"
- F: q! m. h, c/ r- hPrint "您输入的增广矩阵如下："
! d4 D+ j, h' E$ 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"))
For j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
' s4 j* p, z) D+ B# ~Print a(i, j);
% F; ?* T( t- D: ]3 Z9 L9 F/ w# r2 zNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
: d: |) h% H9 r' W: B2 g7 e2 V% ePrint
Next

) z0 f' D* F& j, d: IFor k = 1 To n - 1 '开始消元
6 {8 R1 X1 [2 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！"
Exit Sub
Else
# H; w# Z" r# j2 A6 R6 W' o9 nFor i = k + 1 To n
3 G' H% V# ^/ o; N6 i+ a2 {- L  Q& ml(i, k) = a(i, k) / a(k, k)
) Y( l8 A. e# p9 P, y* EFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
  W/ C. n0 @' ?1 s8 C" qNext
+ e% Q* O2 A- K$ `; U: cD = D * a(k, k)
( z6 y/ J/ R7 {End If
) n9 `+ l- d- f0 ^Next 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！"
# \- q9 f) S' |Exit Sub
Else
D = D * a(n, n)
- Y; v* M+ u6 J/ REnd If
Print "--------------------------------"
3 q# G* M1 h) Z( i: RPrint "系数行列式的值是："; D
' S5 j: g! _+ {: t5 L: dx(n) = a(n, n + 1) / a(n, n)
6 [, m: @: O. y1 a$ z. p7 u& BFor 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)
2 H  W. d# C! q3 C: ?) _m = 0
$ H* O% A* ]  E! }Next k '结束回代
" j) }+ k$ }2 l+ J5 I
8 T# b. Q  {, Z5 l& w* z3 B" RPrint "--------------------------------"
! b2 V: w6 G. c  RPrint "方程组的解如下："
2 x( q3 x& i6 o6 n& B; O) O
9 o; P8 X# j. ~1 p- CFor k = 1 To n
7 @& m7 o. U  a# W: pPrint
Print "X(" & k & ") = " & x(k)
! Z  c+ Z- G0 ?  s" b+ ]$ S/ F+ ^1 {Next k
- T4 U. i9 L3 p+ iPrint "--------------------------------"
* c6 @* u9 C* y3 W$ ~3 s/ T- aPrint "其中各行Ax-b="
0 S" V' l6 d5 W: oPrint
, F& |' o. h: J  z( h$ E  }For i = 1 To n
t = 0
For j = 1 To n
/ @0 p3 T  T" M. a- E# Ct = t + a2(i, j) * x(j)
$ P. j" [% @1 c/ NNext j
t = t - a2(i, n + 1)
5 h$ w5 L2 C' \' p; S' |Print Spc(5); "第" & i & "行："; t
( l, p3 b) f* n+ ^' x0 t& XPrint
4 ]6 }! q$ X; B1 f  ^( V$ C  CNext 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