[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
, s! \: l% b3 G8 hDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
5 t! V# \6 E6 k# X. j: ti = 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))
' z0 R7 |# v$ gReDim 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
7 \! }9 e2 v. k7 ]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
, p/ V, h, k0 f% p+ `/ v0 h; m8 Oa2(i, j) = a(i, j)
Next
" g- C2 i" g' {+ d+ D8 r9 u* oNext '将a()的值全部赋给a2()
m = 0
D = 1
9 W5 H( |9 P9 bReDim x(1 To n)
Print "--------------------------------"
Print "您输入的增广矩阵如下："
& X; n# W; c, ?. ?4 v- |+ H/ dFor 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"))
For j = 1 To n
6 y5 f; A7 F) O# e" Ma(i, j) = Val(Left(s, InStr(s, " ")))
; a% @/ g4 M* {1 x% Hs = Trim(Right(s, (Len(s) - InStr(s, " "))))
: k7 t) v/ W1 M- }8 B7 X2 VPrint a(i, j);
Next
2 o/ ~+ g% y. P6 Ta(i, n + 1) = Val(s)
Print a(i, n + 1);
9 O' R0 }+ K, wPrint
' ^3 h- k8 u( y5 oNext
7 O7 y( ]. {, U9 ^) e- {8 \  e
9 F+ T& y6 Y0 \  _' }For k = 1 To n - 1 '开始消元
* r3 I7 ~) r6 `7 N, y! V7 X9 Z: HIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
! g* N) W1 j8 \$ {3 xExit Sub
& N$ m+ o1 D0 q; Q$ CElse
* j. Z& m: I/ }( s: aFor i = k + 1 To n
$ v2 M. ~, {% ll(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)
$ S3 ?$ M& H* |8 YNext
, G. V5 v9 ?/ X0 g; C6 |% i  A! FNext
) K  f; R- \/ ^0 mD = D * a(k, k)
- o; g$ {3 \# `% B% @' `. D' JEnd If
Next k '消元结束
: o2 c: x8 ?' S$ S# ^: S6 b% IIf a(n, n) = 0 Then
* R2 U& a5 p' O2 a' J9 kMsgBox "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！"
# {8 f/ D1 C/ J) u8 {Exit Sub
Else
D = D * a(n, n)
8 X/ P3 ~$ I$ G% J! @) H7 Y9 ^End If
3 X# j/ n! a% R* B4 E9 K/ oPrint "--------------------------------"
- Z5 w6 a  Y: J' uPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
3 R7 e: [  b9 Y' m! [For k = n - 1 To 1 Step -1 '开始回代
0 x0 F! a0 p1 v5 Q7 U4 HFor j = k + 1 To n
$ t) K" C' |2 \1 im = m + a(k, j) * x(j)
Next j
' a! p+ v+ U. M3 y( u8 lx(k) = (a(k, n + 1) - m) / a(k, k)
) l: B5 G4 ], Hm = 0
Next k '结束回代
0 H! m, E3 q$ l2 ^7 |  N
; q% Q! H8 g: J7 H/ _; HPrint "--------------------------------"
  }7 i3 a" N) T# @Print "方程组的解如下："

0 d; P4 i- q/ ~) Q- G) QFor k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
Next k
+ ^/ p2 g+ U, E# B$ z+ PPrint "--------------------------------"
1 P" O# H# C# v9 Q* w+ QPrint "其中各行Ax-b="
( x3 T7 ^. f5 g4 r0 xPrint
For i = 1 To n
; F2 W0 b3 E5 P+ ]! Z! h5 J3 p# [t = 0
For j = 1 To n
t = t + a2(i, j) * x(j)
" j. P2 o/ B/ {) hNext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
- Z) y# n# \2 I. W! lPrint
) S2 ]9 H- C, JNext i
3 q7 a. M4 F; z/ y. c) H  d* G
4 e* R' K( {# T+ b4 `- \/ wEnd 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
% Q$ Q+ N4 I7 Y. X* J# }+ X% k" Bi = 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)
ReDim Preserve l(1 To n, 1 To n + 1)
1 |* w+ B& O2 sDim 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()
' |' b3 _/ z9 s3 yFor i = 1 To n
4 `% H4 ^0 J- @& H& V) b5 Z- U) D/ gFor j = 1 To n
8 C+ h0 h5 \) Ma2(i, j) = a(i, j)
Next
2 W" H+ x/ k) e" K" z8 {9 M2 wNext '将a()的值全部赋给a2()
m = 0
" j$ z3 `% s) O/ XD = 1
& l2 m0 G% w; U8 [8 l0 E, hReDim x(1 To n)
4 v0 X1 N4 O/ i* Q; Y* GPrint "--------------------------------"
/ g3 t6 B3 _2 P; g* }5 vPrint "您输入的增广矩阵如下："
% P. v, ], Y. QFor i = 1 To n
0 z0 _9 d' W( es = 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"))
& L7 T0 }: U6 J' y* `For j = 1 To n
: }% h) N: p) @! O% Za(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
; V- e! M  m- p2 W: R% {Next
a(i, n + 1) = Val(s)
Print a(i, n + 1);
/ P; t' M% p! V& ?0 |7 MPrint
! c$ \0 S5 {% M0 P3 E( UNext

/ f$ T- }! G! `0 Y# g8 \' OFor k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
+ `* e* ~# p) ?  pMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
0 i2 C3 \8 w+ p6 k. yExit Sub
Else
For i = k + 1 To n
, N. z# U- `4 V4 R3 k2 Rl(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)
# Y& t- X# \# G1 r0 b/ dNext
, j( v+ E5 d7 I" w5 fNext
4 f  P! Q5 m, ]4 w) LD = D * a(k, k)
  r3 L% b! i8 h/ K7 _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
: }6 Q# R) ~) R. `/ X0 VD = D * a(n, n)
End If
0 m( r& h& l# `0 W. y5 H- }Print "--------------------------------"
Print "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
  e  ~5 ?. D. n1 X; [6 \9 J' `For k = n - 1 To 1 Step -1 '开始回代
+ m8 J9 Y$ i7 Q! tFor j = k + 1 To n
( ?4 |0 W; f& l7 t- U& D9 gm = m + a(k, j) * x(j)
Next j
x(k) = (a(k, n + 1) - m) / a(k, k)
' L+ R; N, y- ?0 O7 j3 X6 Mm = 0
6 ~5 k: r% p% o# w) d7 \Next k '结束回代

: o3 I. A. k/ [; y' A9 jPrint "--------------------------------"
; W0 N* d" R) x4 I# l" cPrint "方程组的解如下："
4 L4 v! G% M6 b9 N- Y. I4 [
For k = 1 To n
Print
! S* Z0 S3 q1 O% U- R) V+ BPrint "X(" & k & ") = " & x(k)
5 y9 C8 Y. [5 K/ ?Next k
# m0 E* c. g9 O2 v" w/ c) p+ x! wPrint "--------------------------------"
Print "其中各行Ax-b="
! Q) {3 n2 X* s9 M8 TPrint
For i = 1 To n
& h6 t( ^4 m4 E5 s6 L4 V6 ~t = 0
For j = 1 To n
  i8 N' C. N/ J, Ot = t + a2(i, j) * x(j)
Next j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
3 D, L9 R$ E1 h% q8 g! bPrint
Next i
+ n: s- k* O% l8 P/ b' L
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