[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
/ s! Q5 E0 I! U% g8 fDim 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)
6 Y- H$ U4 r- w% vReDim Preserve l(1 To n, 1 To n + 1)
7 O/ ~! d2 W% J# ZDim 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)
Next
3 u) L. i- Z1 o+ O; oNext '将a()的值全部赋给a2()
m = 0
6 ]: W+ Y/ K9 LD = 1
ReDim x(1 To n)
& W) k& w2 ]* y! o4 K, bPrint "--------------------------------"
: Y% Z4 P9 J7 V0 XPrint "您输入的增广矩阵如下："
For i = 1 To n
' f! p1 G" N) n& q* f/ }- F9 N8 O. ^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"))
$ O" I3 u! r# X% KFor j = 1 To n
$ i' F' D" x0 q, \5 sa(i, j) = Val(Left(s, InStr(s, " ")))
& I: r" L/ D3 s& ?% v$ S1 t  [s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
a(i, n + 1) = Val(s)
# b  k% ^7 V5 |Print a(i, n + 1);
Print
Next
4 i5 O: m3 r% {) `8 w$ w2 Q6 `7 b
For k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
5 k, Q1 n2 P: C. Y( u& c4 O0 CMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
- ?3 t1 {& c7 t% E) i- OExit Sub
" ]" }8 k4 N  ?+ VElse
8 f/ Y' e. |/ I7 x4 n9 Y) H' B4 b5 ~For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
4 X6 m% C1 d4 vFor j = k + 1 To n + 1
3 g3 t$ u* [7 Y' S2 n# R( Ca(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
2 t, N4 O& I6 v% o6 RNext
5 O5 m3 ~/ s- ]  c2 A$ K5 h! QD = D * a(k, k)
# i4 k$ ^* d% Z4 ~5 U: A( x; p+ ~6 tEnd If
/ n2 @( {- b: e0 Q/ [& ?  nNext 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！"
Exit Sub
9 ^' W: ?7 V. N* T' c3 @8 qElse
" S& Q* b( ?( K8 h& W2 DD = D * a(n, n)
: M, \+ t) K  x+ w' `End If
9 T- c: \; T7 C4 k4 DPrint "--------------------------------"
6 w7 I5 M" Z' L9 [# sPrint "系数行列式的值是："; D
/ t; Q0 l2 C. A, U% J# u2 _x(n) = a(n, n + 1) / a(n, n)
For k = n - 1 To 1 Step -1 '开始回代
1 E3 Z( a7 S8 r- X0 S& O; [For j = k + 1 To n
8 g- J" y1 m. I1 F3 D" ~. o  qm = m + a(k, j) * x(j)
Next j
; V+ u" M, q2 c2 _+ i3 Ux(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
: H2 l" Q6 k; F( Q8 w$ ]5 j5 h" z4 ^Next k '结束回代
! e3 d; W9 R8 ^7 p9 i6 w
Print "--------------------------------"
Print "方程组的解如下："

7 I$ n0 [. w0 L4 c/ `. J# DFor k = 1 To n
0 B# n& W& {5 O" s8 T, {0 nPrint
- R: ?# r9 a; g4 b  I: N+ J( uPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
Print
- n8 `0 N3 D5 |' {* k2 k) XFor i = 1 To n
% q; N6 l4 b8 v7 u8 M+ s# I- et = 0
For j = 1 To n
3 f+ [) X( n  O0 Wt = t + a2(i, j) * x(j)
Next j
% K' O  C. T" k* v. d5 t+ ^t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
Next i

# v9 G! R2 x6 C' c7 W3 dEnd 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
- L* j" M" K) j: Y; j! xi = 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))
5 u0 B8 @+ Z% z$ d8 B; J% }, QReDim Preserve a(1 To n, 1 To n + 1)
( z* Z* w  R3 [8 h4 f$ nReDim 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()
/ l0 g+ z7 j" B2 m- {9 p1 jFor 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
0 }7 t/ z- K3 R4 \1 TD = 1
ReDim x(1 To n)
Print "--------------------------------"
5 @; f  `- r& {+ ?Print "您输入的增广矩阵如下："
/ g% {# {; m: j" B7 t. {For i = 1 To n
( _8 Y! x1 b! X) is = 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! ~' i  [For j = 1 To n
& Q+ q% e7 m, F% `/ ^+ J" C4 la(i, j) = Val(Left(s, InStr(s, " ")))
3 ~; d% ^  C2 Y: x. a6 gs = Trim(Right(s, (Len(s) - InStr(s, " "))))
! {. `5 A! U$ }9 _8 u7 SPrint a(i, j);
Next
9 N2 D! f. H7 \% c* Za(i, n + 1) = Val(s)
Print a(i, n + 1);
& J  c* \; H$ f( }. OPrint
2 @. [: @5 X4 H! ^+ F9 XNext

For k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
4 N- ^( p  E& kMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
" k: _- _( h- ZExit Sub
Else
For i = k + 1 To n
2 ~3 F! E. k7 e; p1 t' hl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
7 @8 t/ [: P) Wa(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
% \5 Y: A6 ^) q* j- H" @Next
D = D * a(k, k)
End If
9 @- \  Z2 ?( NNext 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！"
# @" F7 D) G# P3 L+ `0 Y* \9 AExit Sub
4 i0 B, S" N$ E( |Else
D = D * a(n, n)
! O0 n+ `/ M/ Y" I- f, ^" tEnd If
2 Q* y1 R. ?# R& t  G0 c2 j9 @Print "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
4 A  Y' |. s( Q6 c0 z3 ~, UFor k = n - 1 To 1 Step -1 '开始回代
. a: H, R. w( u7 k2 q$ r& bFor j = k + 1 To n
3 o1 q! [! p6 Fm = m + a(k, j) * x(j)
Next j
8 ]# l  a4 _0 q! Q# nx(k) = (a(k, n + 1) - m) / a(k, k)
. [5 n# W  x/ L+ cm = 0
Next k '结束回代
1 H, ?; r( l' a0 G
Print "--------------------------------"
Print "方程组的解如下："

( D% [2 @5 j: `( M" [- n( pFor k = 1 To n
4 c" t3 a) F% hPrint
+ B% u' L5 O$ l9 g+ j; h1 I+ f, KPrint "X(" & k & ") = " & x(k)
9 s$ h  g/ x+ }" y% ONext k
$ ^% [0 p; a1 |& J8 C, ~Print "--------------------------------"
' Z( s$ Z7 W, @$ k; A" uPrint "其中各行Ax-b="
Print
For i = 1 To n
t = 0
% t6 ]/ X" }, @2 F+ sFor j = 1 To n
t = t + a2(i, j) * x(j)
" G7 `1 X& Z+ R! S6 XNext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
Next i
0 y/ {7 M* Z! Y+ U
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