[讨论]高斯消去法---这是用VB编的

god

Private Sub gauss_Click() '高斯消去法
3 T+ H* ^/ a3 A$ nDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
i = 1: j = 1
& Y8 l2 D; \: Nn = 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))
0 y) H1 Z2 o" Y0 d9 r4 cReDim Preserve a(1 To n, 1 To n + 1)
ReDim Preserve l(1 To n, 1 To n + 1)
% D* N5 f" r! ^  R" ]Dim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
* D" k  Q$ Y; IReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
3 f4 L. L5 f+ Y) A" w8 z* @For i = 1 To n
For j = 1 To n
( Y( ]" j  ^2 c; ^: I$ c7 o7 Pa2(i, j) = a(i, j)
Next
Next '将a()的值全部赋给a2()
m = 0
2 `5 |0 ?4 z2 W* y1 hD = 1
ReDim x(1 To n)
4 J$ g/ q' G# K% u, JPrint "--------------------------------"
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"))
2 Z" Y0 k0 u5 ~5 ^- @7 PFor j = 1 To n
; I* Z5 v3 a) i/ H+ _5 ~- X( }a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
: B+ N1 d  G, s7 @' E6 @Print a(i, j);
# i% }6 x8 [0 x; x* ]0 Z3 |+ VNext
a(i, n + 1) = Val(s)
* B! ?3 q7 H' j  X' i0 L0 b# `Print a(i, n + 1);
2 F5 C1 n0 y. f9 E1 x: _Print
Next
8 {* Y5 r  d$ F: y5 A) a/ W
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 j- R% p; v7 l( ]- @Exit Sub
Else
For i = k + 1 To n
l(i, k) = a(i, k) / a(k, k)
+ @+ G0 L, J0 V2 c4 B4 n( PFor j = k + 1 To n + 1
a(i, j) = a(i, j) - l(i, k) * a(k, j)
Next
$ r' Q0 q) y$ K* Q( N% VNext
D = D * a(k, k)
End If
& z) M) ?. x. p' f% V: lNext k '消元结束
3 T4 B3 z' @, y7 XIf 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)
4 |4 z7 |; n1 q/ v" jEnd If
6 V* z' J5 T( U4 mPrint "--------------------------------"
% x& y1 c( S$ r" ~; dPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
  d* H7 c+ i0 J2 q/ \1 GFor k = n - 1 To 1 Step -1 '开始回代
For j = k + 1 To n
m = m + a(k, j) * x(j)
6 ]6 g5 }3 q7 T7 Y& Z9 ^) KNext j
. m' c9 G- R8 R7 \) p. _; Fx(k) = (a(k, n + 1) - m) / a(k, k)
4 a/ w/ \" c, G, [3 qm = 0
5 p8 R" |* i. J( ]* zNext k '结束回代
7 W+ z! `5 y! d( q6 {) V4 L  `* N5 L
# m4 l9 `7 V5 }" i- IPrint "--------------------------------"
( m$ R/ S" |+ q. rPrint "方程组的解如下："

For k = 1 To n
Print
Print "X(" & k & ") = " & x(k)
Next k
* W3 ]/ U+ s% y: pPrint "--------------------------------"
Print "其中各行Ax-b="
/ C1 _, k7 Y- b" j$ bPrint
For i = 1 To n
& K+ O* l! z2 }3 _& L+ g2 P; ot = 0
9 y6 n( ]$ k9 {* t6 W9 a3 T: hFor j = 1 To n
: f  L( [. d' v6 `& s# Z* }t = t + a2(i, j) * x(j)
Next j
$ [# O/ M5 a7 m( k. qt = t - a2(i, n + 1)
  V/ D; m8 A8 X3 d3 [4 q; zPrint Spc(5); "第" & i & "行："; t
8 z+ j6 P# f& cPrint
Next i
  N+ F! K& [* C: c# h6 I! {
) G' o4 {: K3 [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
$ p) `, x7 @1 \: Y; C( X  x: Pi = 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)
' p# y2 U' |1 ~: [' k2 `) q, [Dim k As Integer, D As Single, m As Single, x() As Single, t As Single, a2() As Single
  F5 L2 S  y, b5 }$ i* c* UReDim Preserve a2(1 To n, 1 To n + 1) '为方便求Ax-b而设的a()
" y1 d+ l$ f8 R0 tFor i = 1 To n
4 p( m, ~8 N! c/ L! GFor j = 1 To n
8 t4 H( e0 V5 N$ H% ?0 ^; m5 J% {a2(i, j) = a(i, j)
9 p" u  ]& W7 u: V# uNext
: _& _  b4 N8 ~2 ]. jNext '将a()的值全部赋给a2()
m = 0
D = 1
2 n( V! v4 r2 f1 |2 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"))
For j = 1 To n
! _( I: q8 z" \9 ua(i, j) = Val(Left(s, InStr(s, " ")))
6 t* X- Q0 Z# F0 _7 B" H0 ~s = Trim(Right(s, (Len(s) - InStr(s, " "))))
- u- W4 ]. i3 N1 r! t/ [2 R4 ZPrint a(i, j);
) @6 K' E8 V" C; i& U  m; FNext
a(i, n + 1) = Val(s)
Print a(i, n + 1);
Print
Next
- m* d2 Z" K4 m
For k = 1 To n - 1 '开始消元
6 x2 K* u, a6 j. xIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
( B4 f! ^; H+ DExit Sub
Else
For i = k + 1 To n
. s: _  f$ @7 f0 U0 Ql(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
2 g: d7 n. ]8 p+ n+ `3 ba(i, j) = a(i, j) - l(i, k) * a(k, j)
" `; D4 f# t/ g8 j7 M" {$ v& `' ]Next
Next
: }" |& y2 w* |/ D, C9 O! CD = D * a(k, k)
End If
* H" _2 A/ r4 Q9 Q2 E. J3 m& BNext k '消元结束
6 P3 R8 ]+ U6 f+ A+ l  Y1 QIf 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！"
8 W$ q: o/ J; B9 BExit Sub
& v4 v! B/ D( a# ~  B. E* y. hElse
$ ~( b2 w- l" F7 G6 N1 sD = 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)
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)
1 p5 F, X) _. ^! O1 I" K% JNext j
2 }! `7 w6 t. W6 U& hx(k) = (a(k, n + 1) - m) / a(k, k)
+ P. S# L  L# Q  Z* f! F( B! lm = 0
% p/ C! m  Q& B! }4 t! lNext k '结束回代
' J1 ?: ]+ m; O( K( M7 D# z) p+ w2 T
Print "--------------------------------"
% r* C* a( j& O- n. I& n, v$ hPrint "方程组的解如下："

2 w/ i0 @$ }9 p! T( x. z) CFor k = 1 To n
Print
; u( v: T, B; Q  G* j2 g" a, O6 G  uPrint "X(" & k & ") = " & x(k)
Next k
Print "--------------------------------"
6 W7 G3 ]5 J4 w! U/ GPrint "其中各行Ax-b="
Print
' s, o/ g: c2 mFor i = 1 To n
; h& Z( z9 z; k$ \% c( b, Jt = 0
! d, G; E3 c1 I) F# jFor j = 1 To n
1 s& g' V) O% \$ X" K9 x+ N5 d9 ^t = t + a2(i, j) * x(j)
' i2 H* t3 O) R- u. INext j
t = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
Print
Next i

9 e8 ~4 P3 B0 q) b2 H- l3 O' 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