[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
+ H/ \. s1 @6 T; IDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
5 f" g7 e& f6 i/ [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))
3 X8 C# O$ T$ A% T+ H* m9 p" ]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
- j+ Q, X3 z' [3 a3 b& o* f; ZReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
, U# p, D: Z7 Z, H8 d' a. n# rFor i = 1 To n
: Y7 H! ~' e' D8 H* i4 b0 BFor j = 1 To n
7 b7 C6 S  \5 x+ ?; Ga2(i, j) = a(i, j)
Next
; A' u- J4 z/ r+ b6 r: vNext '将a()的值全部赋给a2()
m = 0
D = 1
ReDim x(1 To n)
- ?/ [  Q, _' r6 w) R# Y+ qPrint "--------------------------------"
: u* r: x# L3 x1 LPrint "您输入的增广矩阵如下："
For i = 1 To n
! A; G2 p5 ]4 x. q( O. t% rs = 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"))
: [+ I' i) g, X- d1 W* qFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
% @- ]- q6 U% {$ Q4 q3 A& YPrint a(i, j);
& O1 h7 j$ X/ SNext
  {0 v! o1 o7 b6 U8 o" j6 t' ?6 [a(i, n + 1) = Val(s)
Print a(i, n + 1);
2 @+ K% ]- \9 u9 G3 cPrint
/ A7 q0 h. |) m! \- lNext
: C3 B$ i7 Z: j$ G3 @* a
For k = 1 To n - 1 '开始消元
) y9 ^  H* K3 q, _1 |1 bIf a(k, k) = 0 Then
& E' E! a$ U- qMsgBox " 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
l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
" u6 J! z: Q5 e9 m" Z8 }! h0 ia(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
- D) z6 v0 m" E% c, v) ]3 R( l; iNext
D = D * a(k, k)
End If
Next k '消元结束
If a(n, n) = 0 Then
8 ]. ]7 p5 E, KMsgBox "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！"
+ ?" g* R$ f- L9 O4 l' k; U! SExit Sub
" a5 a1 {! D( DElse
2 z# A/ ~" @- \: @% QD = D * a(n, n)
End If
! @) N+ d' i* G7 s5 z* VPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
+ [4 N( K, g" L2 kFor k = n - 1 To 1 Step -1 '开始回代
+ j  a4 z+ B$ g* ^For j = k + 1 To n
4 R0 @4 `% T1 R( }5 tm = m + a(k, j) * x(j)
Next j
; N1 s/ ~( u+ A2 D) _x(k) = (a(k, n + 1) - m) / a(k, k)
6 }# @, Q5 ?) Y+ `* b5 M) Ym = 0
Next k '结束回代

Print "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
* A) N- u) C9 d8 e7 kPrint
5 h4 E9 y* Q3 D- l' g& }' @6 p! WPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
" E2 f7 W- K) i* k: q6 l) `, zPrint
9 ^5 A8 t0 w1 \$ XFor i = 1 To n
4 [8 V  U" J. mt = 0
  u2 Q, `9 \) j! |: [( A' hFor j = 1 To n
7 o5 \  Y3 l) Mt = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
: l: v1 ?) L* V) f. E4 n, fPrint Spc(5); "第" & i & "行："; t
Print
- e- @: V6 `# Y# BNext i

End SubPrivate Sub gauss_Click() '高斯消去法
/ y/ K* b, Q4 Q8 w& b. jDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
. F* \$ J0 P" N) W0 Li = 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))
" f+ k4 L! p" p! K8 n4 tReDim Preserve a(1 To n, 1 To n + 1)
6 {) N2 S+ v6 q1 u1 d8 [& vReDim Preserve l(1 To n, 1 To n + 1)
5 a' f. Z4 v) U$ 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()
+ S$ j* k0 }/ Q/ e( G, a; BFor i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
, f" g% l0 ?% r. p# KNext '将a()的值全部赋给a2()
% Y. L/ L* X% a: d+ Nm = 0
* W- U# g7 i+ o% s' ?$ y( aD = 1
ReDim x(1 To n)
Print "--------------------------------"
$ g' b6 n7 C7 L# pPrint "您输入的增广矩阵如下："
8 f  M! O4 n2 F( 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"))
1 M9 N* c1 ~" K. i4 dFor j = 1 To n
; f$ _, G+ D9 \7 qa(i, j) = Val(Left(s, InStr(s, " ")))
) A* a0 P  {$ t+ p* V% ^s = Trim(Right(s, (Len(s) - InStr(s, " "))))
7 |2 X" a6 ?% I. s; C8 aPrint a(i, j);
Next
a(i, n + 1) = Val(s)
7 {. C3 z% C0 gPrint a(i, n + 1);
/ F- y& _# [; ]# c8 D3 T2 jPrint
Next
0 c# h9 J- h" s! ]! ?. c
0 X1 j# s+ p# yFor k = 1 To n - 1 '开始消元
0 K  ~4 z  [9 c! _$ T" O3 _If a(k, k) = 0 Then
* J4 \. o/ S$ b; g1 DMsgBox " 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
l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
2 z) x9 X( Y* E9 }% ^5 \0 |) T# Va(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
Next
! B2 U4 f6 T% I9 t- J+ sD = D * a(k, k)
0 y/ |: I& k! a# T$ n  M1 UEnd If
Next k '消元结束
  M# J, c8 s; A- Q" T# g7 f) YIf 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！"
# D' A- e3 W6 E+ X# rExit Sub
( ]/ C( f3 X) y1 ]6 fElse
D = D * a(n, n)
8 k# ?8 H* e1 U; }End If
Print "--------------------------------"
! s% t) N0 Q# S; k0 g: y* }/ B( B2 qPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
' e! r* z: |2 H! {! g( QFor k = n - 1 To 1 Step -1 '开始回代
2 h4 }( ?# V6 a/ [$ U+ @8 a  OFor j = k + 1 To n
& v/ k$ g4 h: ]4 \m = m + a(k, j) * x(j)
, a; K% |: ]  f- P: l! XNext j
x(k) = (a(k, n + 1) - m) / a(k, k)
% G& W/ V: c: g% |, P- ]& sm = 0
! o5 j) k) x3 g3 E5 a. KNext k '结束回代
( o9 F) G2 s6 u4 w
( P# X: _# t( y- o  UPrint "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
4 q8 u0 W7 X% pPrint
Print "X(" & k & ") = " & x(k)
Next k
7 l  @2 o( g. ]4 {  l2 |( kPrint "--------------------------------"
$ z; y& l- n  u7 E% fPrint "其中各行Ax-b="
! S2 J) v! y$ D& g/ e  s/ s% M$ nPrint
6 T* V0 z9 \% s, r! D3 ~7 @* [For i = 1 To n
t = 0
8 L& ]: Z! ]0 r% vFor j = 1 To n
( ~$ h: Z/ ^' A& nt = t + a2(i, j) * x(j)
9 e  H* g; E# f$ {- m( R9 }Next j
t = t - a2(i, n + 1)
7 o  J5 ?: ^9 m+ f. ~$ WPrint Spc(5); "第" & i & "行："; t
  g; X" W; q1 Q6 `Print
8 S5 U  C5 k) `& INext i
% O% z* P7 d2 o; ?8 g- z  }
End Sub

zqyzixin

我也想了解了解！！！先顶一个

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>

ch123en123

下载学习哦