[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
9 x$ u: y; F9 c' A, ~4 Q- p( TDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
! F% l6 w% O9 i. T  Ni = 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))
, P, `9 V- S4 J- s! E# aReDim Preserve a(1 To n, 1 To n + 1)
( y& S2 |1 f+ Y  eReDim 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()
2 X% ]$ F8 M7 o; l0 GFor i = 1 To n
5 B8 k$ K, Z# n# qFor j = 1 To n
/ _3 V. M0 d) s0 |a2(i, j) = a(i, j)
! J- R% z8 w# F/ INext
  L) ~5 {2 b' v) Z% eNext '将a()的值全部赋给a2()
m = 0
  v" c" m# D& c0 q! T# PD = 1
1 d. b6 p3 s  ^( c. w' W5 iReDim x(1 To n)
6 t4 B4 x" l% `Print "--------------------------------"
6 k) f4 {  F) m2 q8 ~7 D4 ZPrint "您输入的增广矩阵如下："
For i = 1 To n
; V! z; M( W0 F7 zs = 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
9 r' \6 N+ q. e' ]a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
$ d5 w: t4 c6 YPrint a(i, j);
8 z3 Z- l9 F8 P/ n3 J, _Next
& K0 M' Z. i6 g/ |' ]1 Oa(i, n + 1) = Val(s)
Print a(i, n + 1);
; Y! ~! c1 w2 A3 s: k% }( CPrint
Next

4 |8 q7 L! R' @! s9 F' E  m; R: ~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！"
$ {3 _4 g3 q! \( PExit Sub
Else
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)
Next
' s" L; U0 I" V0 L8 SNext
5 j& i- E7 f% A* v) wD = D * a(k, k)
9 t  D5 M- `4 \' j/ [. X- nEnd If
Next k '消元结束
3 X( @% R3 n; d( f" \If a(n, n) = 0 Then
. v* y, L! D& ]# `) E# I" {' PMsgBox "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！"
/ H# n5 n/ o3 \! D" ?1 Z9 BExit Sub
: ]: e9 Q5 ^+ b- Q; d; QElse
D = D * a(n, n)
$ W- w0 U- t! r- TEnd If
& J' |. x. R# D) _4 s# L4 G5 fPrint "--------------------------------"
  T+ K# B5 [6 I( c" L" }6 e0 nPrint "系数行列式的值是："; D
0 e6 I9 y1 a' Bx(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
m = m + a(k, j) * x(j)
' _- ^: ~3 C( Y1 c9 f3 rNext j
7 {6 ^" _) H( Mx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
: K% I0 z  K- H6 G) @5 z& ANext k '结束回代
- d/ }5 q+ _9 O5 n- [% L" I
Print "--------------------------------"
, K3 Q& l  u" u5 {( U+ u9 JPrint "方程组的解如下："
! b- }* d5 \3 F" }
9 L6 u8 n2 ]5 jFor k = 1 To n
Print
+ u( p+ y, d1 j3 iPrint "X(" & k & ") = " & x(k)
* b  l4 h+ S5 w( J$ G/ ~+ dNext k
Print "--------------------------------"
Print "其中各行Ax-b="
2 W/ v7 B2 {  I6 fPrint
$ H" |; W* }1 @) }0 t& l0 e: [For i = 1 To n
t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
. j8 W: g. Z3 w/ b5 i$ [  CPrint Spc(5); "第" & i & "行："; t
6 j% Y. g. p! E. d0 `Print
2 E$ w- {4 V  i! R. |$ lNext i
& p& w! @4 D8 ?% c
End SubPrivate Sub gauss_Click() '高斯消去法
- W+ ^( H/ e5 A9 K5 cDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
/ E1 K6 Z  x' ^- o0 on = 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))
& v& m# e  z4 t/ q" rReDim 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
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
/ g0 [4 ^+ Q4 f0 O( U% ?/ La2(i, j) = a(i, j)
# F& D9 ^# ^# x0 j+ c; O2 E0 hNext
  f4 O9 H' G( x# _: R, ^Next '将a()的值全部赋给a2()
m = 0
D = 1
3 y& V, t2 i5 _. X. pReDim x(1 To n)
3 ]5 v3 ^4 f: D7 G$ H$ {, q. `Print "--------------------------------"
) C+ H: a3 H" I1 N: rPrint "您输入的增广矩阵如下："
For i = 1 To n
% D' l! I6 S3 O- R/ B; Ts = 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, " ")))
1 T! r! M4 X" vs = Trim(Right(s, (Len(s) - InStr(s, " "))))
4 _6 K* T5 z8 ~2 i' H/ e* FPrint a(i, j);
Next
a(i, n + 1) = Val(s)
, y1 r. U* V, q, K( H3 u3 |  NPrint a(i, n + 1);
5 F0 R# G, `) N  x: QPrint
9 b: ?* }( }9 U* H3 yNext

( J( t9 j' F5 k  T9 b& 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！"
+ _: ?6 j1 e; Y1 dExit Sub
Else
For i = k + 1 To n
  c6 t. H1 v: V0 J/ ?l(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
1 K- l' i& C( o5 J" ~& g9 xa(i, j) = a(i, j) - l(i, k) * a(k, j)
& e& _; J. |3 c& l" G; P; X5 z' UNext
, o! w9 n1 U/ G! S$ DNext
* `+ n: ?9 v% BD = D * a(k, k)
End 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！"
& e% I; B) l2 }Exit Sub
Else
D = D * a(n, n)
End If
7 s3 C' }0 ^6 }" QPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
2 s; n9 I3 S: r3 k4 _For k = n - 1 To 1 Step -1 '开始回代
; T  A0 y+ }- x' kFor j = k + 1 To n
m = m + a(k, j) * x(j)
- V9 ?, [) s9 x2 aNext j
x(k) = (a(k, n + 1) - m) / a(k, k)
1 ~: g0 H4 J) Rm = 0
& A1 i& k% E; K3 C7 A$ s) g# n- dNext k '结束回代
1 Y+ Z6 Y( R" S9 b- j  E$ p
% P& b* j7 O0 l7 j" qPrint "--------------------------------"
Print "方程组的解如下："
% [5 q3 p2 T% |4 B
For k = 1 To n
5 a. K+ F: @6 a) P, vPrint
Print "X(" & k & ") = " & x(k)
Next k
! p7 n$ R. \6 s1 E1 O0 j$ P  bPrint "--------------------------------"
Print "其中各行Ax-b="
Print
For i = 1 To n
t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
% j7 M0 D9 S: h, h* LNext j
% S% U* ]3 h3 B+ L# w4 xt = t - a2(i, n + 1)
$ w! |3 U, r' h9 W4 M9 J- G- ]Print Spc(5); "第" & i & "行："; t
Print
2 U9 x- {" g! ^Next i
* [+ K% P+ N7 P" Q0 b
0 o& Y0 h" Z8 m6 {3 k  {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