[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
' a5 g! v1 \$ c! y7 n4 ci = 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))
) _6 t9 |% m( x+ l  ?8 tReDim Preserve a(1 To n, 1 To n + 1)
( ]: z' W- E; b6 K6 @ReDim Preserve l(1 To n, 1 To n + 1)
) ^4 S) ~7 q- K$ aDim 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()
! R! p" O+ q2 R1 WFor i = 1 To n
- ^. T5 n+ i$ m) rFor j = 1 To n
% X: ]2 s* s' r; ya2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
D = 1
ReDim x(1 To n)
Print "--------------------------------"
1 r5 M/ L  Q( X  n3 n) X6 kPrint "您输入的增广矩阵如下："
For 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"))
: T1 s  f, f+ i  mFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
! U$ ^9 B  p$ n- m- I' Ss = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
* _7 x$ Y! L$ H! B: DNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
4 r6 q5 e* w9 t0 J* z9 KPrint
- P; Q$ w3 w9 b3 Z/ f8 cNext

2 g& w. u4 o7 H5 W1 c+ ~' ~0 dFor k = 1 To n - 1 '开始消元
+ Y8 k0 }8 z5 Z! }! TIf a(k, k) = 0 Then
, q/ p6 j% B. Y/ gMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
" l* |6 B' i# V; GExit Sub
6 P: b2 @' z' s' e2 YElse
8 j) Y# _$ c8 r' ^: e: [For i = k + 1 To n
! m8 _) ^8 O, b5 bl(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)
6 T( d1 n# W7 s+ F: Z" s' \1 M. qNext
' e7 I7 D, e: E) FNext
9 ^8 S( c  B5 t) ]9 G; Z' n# M8 xD = D * a(k, k)
3 ?, W5 y& X& @' QEnd If
Next k '消元结束
If a(n, n) = 0 Then
, E8 }  m9 e4 U) o2 hMsgBox "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
Else
D = D * a(n, n)
. U, w) B* _. A2 x# ?' w! JEnd If
6 q5 m/ A. |: hPrint "--------------------------------"
Print "系数行列式的值是："; D
2 d$ B! `  y- ~4 mx(n) = a(n, n + 1) / a(n, n)
1 T0 D0 E( i# A! JFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
9 }0 @9 \% c6 j( H# k' N/ Zm = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
! J6 z- a+ k. g* s2 ANext k '结束回代

Print "--------------------------------"
, g# b% N# p0 h2 ~Print "方程组的解如下："

For k = 1 To n
Print
5 H' j( r% a2 C1 w2 U3 z; rPrint "X(" & k & ") = " & x(k)
Next k
6 z* h0 V% u' k" N+ O; q4 GPrint "--------------------------------"
Print "其中各行Ax-b="
5 y3 D. \- J* Z  A/ i$ Q+ Q% ePrint
For i = 1 To n
t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
5 V$ H# I  E; n6 c" K$ l3 }3 ~) a; XNext j
  O. B" y, M4 s# p' W& m0 J- Gt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
6 v$ d$ R7 L  Q* b" O, tNext i
! X# G9 I) N# u6 F# G3 r5 F7 {
End 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
# p7 g2 B+ |5 `- @! ?i = 1: j = 1
, m9 I  {: N1 Sn = 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)
ReDim Preserve l(1 To n, 1 To n + 1)
+ E7 E# r% |6 I1 H  ]Dim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
: y. c. i4 E/ d5 b' wReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
% w3 f! ?; C, k" V/ r' ]7 {For i = 1 To n
: U8 |% y. [' F; j1 V: g1 f2 kFor j = 1 To n
" L! h" A9 ]/ o  ~4 h' Ka2(i, j) = a(i, j)
- d- }* c& z3 s. {Next
Next '将a()的值全部赋给a2()
m = 0
* H7 \# w+ N: _; tD = 1
3 d" o" W3 ]9 t, M& H4 h3 mReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
For 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"))
. J! S; E# X) ?% v& v; T( \For j = 1 To n
! V& Q9 x1 ?: l% d$ h+ j  C+ qa(i, j) = Val(Left(s, InStr(s, " ")))
6 u2 p5 R! D- B! Y" ~" \# es = Trim(Right(s, (Len(s) - InStr(s, " "))))
& Z! G6 V0 c; x6 uPrint a(i, j);
Next
a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
# \1 t% i; F& Z' t' V$ GNext
0 o6 P* {' I, G# ~6 R8 ^
For k = 1 To n - 1 '开始消元
2 @6 F" S% r3 v; ~& x: lIf a(k, k) = 0 Then
  H; |* [6 B% e; {MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
+ v+ B+ T' H. HExit Sub
Else
For i = k + 1 To n
) G# k$ e- o  Y: B, Yl(i, k) = a(i, k) / a(k, k)
/ U% L: `9 Z3 m, T: OFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
3 }+ `0 _. N6 s6 R" z$ P8 K3 h) `: H/ ^Next
Next
D = 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！"
Exit Sub
Else
D = D * a(n, n)
3 Y# y$ v8 }, M( `3 a, @' }% [End If
) J' O5 v3 m3 ~+ o% ?! gPrint "--------------------------------"
# q$ u( Z  h0 a' ~# _( p% a8 CPrint "系数行列式的值是："; D
0 \$ b/ w  N, H7 T) vx(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
% J/ b. g/ a0 um = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
) r$ i( X: h. G* ?- Ym = 0
Next k '结束回代
- a" }/ E% u# X, X+ G, i
Print "--------------------------------"
Print "方程组的解如下："

For k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
3 ^( [% f9 k1 p+ c$ t# `9 c1 hNext k
3 \1 Q# r. G0 K; u( RPrint "--------------------------------"
Print "其中各行Ax-b="
* P# Z! p  W  {' m) C* MPrint
" Y% o3 v2 Z" j+ ]4 @For i = 1 To n
t = 0
9 o4 F4 f( W' h3 g2 S* j' GFor j = 1 To n
) d0 V+ y2 u- D! |* b( C5 |" e! [t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
' q* B8 K$ e( o- X5 e) g! K1 ?5 Z  YNext i

  v- b* }4 r) s' x0 f0 Z: j) P: P( a. VEnd 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