[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
7 p5 [" _$ s( s  H6 U, f. eDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
( J; D! H7 x& n- `! `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))
2 t  F1 U; }& i) c6 p2 QReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
) `  C' ]! E- ?% k( v7 yDim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
6 T, r0 J/ z& @, ~, W4 z! jReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
9 Z! A; a; f: ~/ pFor i = 1 To n
For j = 1 To n
a2(i, j) = a(i, j)
Next
4 a" Y' z' \9 B* ]: m& dNext '将a()的值全部赋给a2()
m = 0
$ U9 h1 ^( X( B+ x. ND = 1
ReDim x(1 To n)
Print "--------------------------------"
5 M5 r, [' ^* \( A3 ~Print "您输入的增广矩阵如下："
% O' z2 r: J. k- z( o4 b/ uFor i = 1 To n
0 G' N9 z: {# q, p, T1 W) ~3 vs = 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, " ")))
! ]% X+ p: a7 a- P( j3 Z7 q' Vs = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
* f8 T" e9 V% C! `# j6 p$ hNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
+ Q3 c+ _, B1 u" gPrint
Next

' }; Z$ \- n4 \: uFor 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
) p( `+ q% H0 A6 v1 H- y! j5 iElse
For i = k + 1 To n
% w7 x+ h4 p. q! b5 Q7 @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)
/ e/ x" W, R7 E& v1 x9 BNext
Next
  G9 b' x8 H! w$ e; V: gD = D * a(k, k)
  I) |3 l, E0 Q* ?0 h& M3 iEnd If
' b: z, \) i2 U' W4 M- I% KNext k '消元结束
If a(n, n) = 0 Then
1 b7 i( G/ V2 j9 c, IMsgBox "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
8 Z$ n  ?' ~0 n1 o% y5 P# kElse
D = D * a(n, n)
End If
. ~3 v  A( _6 Y, W9 _9 w( uPrint "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
, ~' @$ q0 R' B+ {' WFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
; X* t5 n  o$ L% F# Vm = m + a(k, j) * x(j)
4 l$ H) a7 M. R$ C/ ]Next j
2 O; h2 \3 ^8 i# w' m. ix(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
* H) v5 D% |: K% }5 v+ L7 \Next k '结束回代

Print "--------------------------------"
% e0 U; P& d' @0 t$ zPrint "方程组的解如下："
3 {; i2 N  O& O# E; |3 Z* h# [5 o
/ l" z$ X! P8 G# O  c- OFor k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
4 x. A, A1 o  T+ s( Z# xNext k
9 a+ H, s( B0 @/ a- c6 wPrint "--------------------------------"
# Y4 d: \8 e3 ]Print "其中各行Ax-b="
2 H" e0 e$ ]2 Z- P$ `Print
6 {9 w& @7 E( `( J7 [+ WFor i = 1 To n
t = 0
! g, R( M2 {1 q$ a& W7 z. JFor j = 1 To n
. W( Y: d. ?7 I3 M  O2 \; ?t = t + a2(i, j) * x(j)
( k5 z8 j* ?. i7 A. V$ c" O8 QNext j
/ g& J' y; G1 C% J' T9 Pt = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
+ u8 e2 I, L+ I- O. Y* FNext i

/ T  D: T6 W: W& d# X' \End SubPrivate Sub gauss_Click() '高斯消去法
# P. q  I2 X5 F4 J/ |Dim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
5 n, `' R; t5 m  L4 ki = 1: j = 1
( `# W# G  y2 O) H* ?' W" j1 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)
0 E6 g$ ~' {! c! T  u  JReDim Preserve l(1 To n, 1 To n + 1)
" M/ {' o1 w7 N+ XDim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
( B! ~1 i. B, S* p, }ReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
8 ]( D+ q. X7 }/ TFor i = 1 To n
1 z" R- R2 }* u7 E) C: m5 FFor j = 1 To n
# K; E7 ]$ F+ |# S3 U3 j( J' `; ~a2(i, j) = a(i, j)
$ C: I/ d* h& e5 UNext
% M' _4 S( @9 V9 n7 ^9 m% f& mNext '将a()的值全部赋给a2()
& D3 X5 p/ o6 ^& Bm = 0
' _* [  K  f5 X, i3 AD = 1
9 Y# K/ X( ^: N' I8 GReDim x(1 To n)
- ]% o% O( B. z4 I0 t% M0 KPrint "--------------------------------"
4 F1 G. P; M$ f5 w2 ^" p3 k+ F$ {' UPrint "您输入的增广矩阵如下："
For i = 1 To n
7 q) _6 H; R1 V! p8 Bs = 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"))
5 P/ g- {+ U3 b  SFor j = 1 To n
% u6 z% x% s3 ra(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
* e3 c, ^& R3 p* }& a. p- UPrint a(i, j);
( Q3 k! k! z" q' i7 gNext
1 H0 Y$ C$ O# E" \$ Ka(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next

, Z4 q9 P7 |+ ^  o% @4 {2 q' m' hFor k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
* w3 O: ~1 _1 y+ q7 ~" [MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
Exit Sub
7 i, F* h2 @' R  z; a" i$ uElse
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)
2 h! R7 ~' u2 h* o$ q$ b% cNext
8 {4 o  `0 ?" e1 A2 |" A- p: YNext
D = D * a(k, k)
End If
Next k '消元结束
4 R6 ]4 B8 n/ s8 M/ G: b5 RIf 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)
End If
Print "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
$ _1 g1 v: [1 T' h/ {# lFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
m = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
Next k '结束回代

Print "--------------------------------"
& W( E- \2 _/ G! ]" g  z, GPrint "方程组的解如下："

+ o, h' X$ k$ X! HFor k = 1 To n
Print
! F4 H2 s+ \- J) T4 z6 k6 ?- y/ h! @Print "X(" & k & ") = " & x(k)
7 b" d- J, @( UNext k
+ W6 J7 W* A3 @+ U# LPrint "--------------------------------"
Print "其中各行Ax-b="
/ C- A. }1 C) ]! ]& K6 I& LPrint
4 X0 X% v3 ^7 p' c1 P5 a7 PFor i = 1 To n
t = 0
) k0 Y5 r# h2 DFor j = 1 To n
t = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
& |& G7 z8 ?# IPrint Spc(5); "第" & i & "行："; t
Print
' Z4 h2 Z+ p( r; X$ qNext i

0 \+ x: d3 h1 ~5 _5 @6 V! [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