[讨论]高斯消去法---这是用VB编的

god

Private 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
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)
" s- U+ g0 n7 g2 `0 P5 M1 |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()
For i = 1 To n
/ w2 E  I: c) h' Y9 @+ Z( [For j = 1 To n
! f( V+ m: b) W, r6 `% _a2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
D = 1
1 W2 o; J9 A" SReDim x(1 To n)
# W6 d( d: H0 Q- Y% `Print "--------------------------------"
Print "您输入的增广矩阵如下："
, J) `# S' a  @$ m' jFor i = 1 To n
* v2 H. }' v9 e+ i" _8 d6 |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
4 A* R( m* T9 ?" ?5 [$ X( L) T7 ya(i, j) = Val(Left(s, InStr(s, " ")))
: r# b1 e& ^2 a2 hs = Trim(Right(s, (Len(s) - InStr(s, " "))))
8 g5 I9 W& |7 _; w- \Print a(i, j);
Next
; R1 u- I' K! {& u6 Ca(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
$ v9 `  ]! {% r& [* k1 y+ c; HNext

) @! S5 c7 @! m* q6 q1 Q9 MFor 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
+ ~2 n& P, G8 w8 _Else
For i = k + 1 To n
1 a2 ?3 {" A8 A+ M4 ?) l1 sl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
2 |+ [% G; B1 wa(i, j) = a(i, j) - l(i, k) * a(k, j)
, c6 I$ F: H  [8 l% ~. hNext
- j+ ]  |3 F1 _' x1 ANext
D = D * a(k, k)
; z0 J3 }4 b$ d( l$ GEnd If
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！"
- Y- a" q) N  `6 p7 jExit Sub
Else
D = D * a(n, n)
End If
Print "--------------------------------"
Print "系数行列式的值是："; D
7 Y+ \) M, Y, N  i0 |( zx(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
: Q8 d1 C/ r( m5 J3 J( Fm = m + a(k, j) * x(j)
8 X4 T* w& G' lNext j
x(k) = (a(k, n + 1) - m) / a(k, k)
( I$ q! {' w9 q- L; [( Em = 0
Next k '结束回代

. k1 z6 w/ i- N! a& s2 wPrint "--------------------------------"
Print "方程组的解如下："
) L* f6 Q0 e8 e. e
For k = 1 To n
Print
  Y( `, W4 L2 ^& H) M2 _Print "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
Print "其中各行Ax-b="
; `- l: b; E& vPrint
For i = 1 To n
6 ~( G( g4 s- ]# Mt = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
' h. B  g+ H; O" ^* P' ^3 Q2 Lt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
" M/ o* H) d5 x; h1 d3 ]Next i
7 X6 \/ \, T$ q( _# z
End SubPrivate Sub gauss_Click() '高斯消去法
; R/ a+ X8 d2 r2 P! [Dim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
! C2 k( ]. g  C5 ~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))
8 \, K* Z: b% t' QReDim Preserve a(1 To n, 1 To n + 1)
" Z3 q+ r- o7 f; aReDim Preserve l(1 To n, 1 To n + 1)
6 `6 A8 z, [$ n* B7 }" w, e, k2 A# fDim 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()
) n, z! U% A$ i9 J: b( B. H: HFor i = 1 To n
4 C1 l0 T1 X1 C  k: Z  _6 RFor j = 1 To n
a2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
2 D1 q2 [/ W  S; ?- F6 Z% x4 w" m5 SD = 1
) W+ ~- D5 E  jReDim x(1 To n)
, ^+ M' E5 e3 {7 B5 k4 X8 KPrint "--------------------------------"
& m9 J  L$ P1 [8 ]8 I7 UPrint "您输入的增广矩阵如下："
: p. ^- N6 _/ N/ {7 o( Y+ kFor i = 1 To n
* M. O1 l  z( B8 H. I: R" w  |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"))
4 J- `8 i# Q0 Y4 {# OFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
0 G! K7 I9 R* Q% o  MPrint a(i, j);
Next
a(i, n + 1) = Val(s)
: m% n5 C& x( i& [# a4 u& c; iPrint a(i, n + 1);
" f& v9 O) L5 K  h* O( \Print
Next
: _+ c& [- n- P
For k = 1 To n - 1 '开始消元
! e  i  F5 G+ u0 I' \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
  I% o8 Q) Q5 v: r5 K0 bElse
5 y8 v1 p0 G! S& d  S! {For i = k + 1 To n
3 T3 j  d( b" m& jl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
8 k: h' D: M) t$ ]a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
8 [* L9 V, D/ Y) {. r- k! M8 O3 `9 dNext
- i$ H/ R! ~4 `2 @2 O* I0 iD = D * a(k, k)
End If
* F4 a6 @8 n5 SNext k '消元结束
If a(n, n) = 0 Then
' S/ \2 z% B' T; ]+ ?# DMsgBox "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！"
! Y- F: F3 Z* `9 d/ S, d( f  b( \Exit Sub
Else
! @% L* D$ \0 t% C% OD = D * a(n, n)
. p, o" c( B) C  a" Y7 w9 PEnd If
Print "--------------------------------"
+ o1 k' Z% s5 E) Y- N3 Y; q# APrint "系数行列式的值是："; D
5 B& l7 }+ I# b& o$ v8 w1 jx(n) = a(n, n + 1) / a(n, n)
: Z: J; g6 w( jFor k = n - 1 To 1 Step -1 '开始回代
  W0 D! b; C" J- P& }) CFor j = k + 1 To n
6 h2 h( {, H6 M% i% zm = m + a(k, j) * x(j)
( A# w4 F- x, y. K% SNext j
* n- p' Y* E: K% {( z8 wx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
Next k '结束回代
3 T. t/ p' \* F3 _% i/ t
Print "--------------------------------"
. @: K2 S  J, t; J4 p5 WPrint "方程组的解如下："
/ D0 ^: t* C' Y8 c
. m. ?/ K8 M; Y/ \For k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
Next k
8 |/ k2 G3 Z, z: {4 C/ ?: }( QPrint "--------------------------------"
. p/ w: s3 a" T! I, X2 i, APrint "其中各行Ax-b="
Print
& q( d! O7 }+ B  d8 [6 AFor i = 1 To n
t = 0
8 _2 K/ q" }$ Y  kFor j = 1 To n
! g* P3 a/ @4 H" h! k3 u) N, ~& Qt = t + a2(i, j) * x(j)
6 n5 e, ~5 Z0 n5 m/ F# L5 mNext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
$ H; i' u1 B/ H1 GPrint
Next i
, s: [6 n) ~- q0 U* M
$ X  n$ M/ |: ?& W3 M; c6 {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