[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
i = 1: j = 1
) f' d( Q2 o" R. Q* Zn = 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)
: j2 L1 q3 x! \+ z8 }  q. n+ s$ nReDim Preserve l(1 To n, 1 To n + 1)
, i& G! i3 [, y, bDim 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()
3 `/ m; v7 h& y* d! pFor i = 1 To n
# _% L; E2 c1 V. @6 }0 S+ p. uFor j = 1 To n
a2(i, j) = a(i, j)
Next
) R/ R" f8 g- F7 A' \Next '将a()的值全部赋给a2()
/ A- \# F6 k2 Sm = 0
D = 1
ReDim x(1 To n)
Print "--------------------------------"
! T6 U9 m) h; \5 s5 z0 iPrint "您输入的增广矩阵如下："
% `/ R' @. A' ^+ x# OFor i = 1 To n
* g- A# M4 w. E( Cs = 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"))
; ^3 d7 v8 [3 {5 e! `# W1 DFor j = 1 To n
a(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
a(i, n + 1) = Val(s)
/ ?" V% K: E! z2 z9 k! BPrint a(i, n + 1);
Print
Next

For k = 1 To n - 1 '开始消元
( @9 c& R& \6 F/ R( ZIf a(k, k) = 0 Then
MsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
0 w; t5 U( k! y+ S, cExit Sub
# s2 Z2 G# {" |4 y; _, o) s% \Else
# D: Z; {* X! h! @8 NFor i = k + 1 To n
6 c' i) G+ W: \5 V$ @! Tl(i, k) = a(i, k) / a(k, k)
For j = k + 1 To n + 1
8 R* F) x) `* q. F) Na(i, j) = a(i, j) - l(i, k) * a(k, j)
* o' c; W: B9 ?( ONext
7 m- M+ ?0 B( M5 ONext
D = D * a(k, k)
End If
% C! o: f' B3 m9 o4 ^  jNext k '消元结束
. x" e  x& Z. `8 r0 eIf 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
: n2 F! J/ _, s$ m% L, w, d+ A+ @4 HD = D * a(n, n)
: U6 f; G& K4 W$ {3 }End If
Print "--------------------------------"
" i9 Q1 H8 {$ y. V6 I, m1 K6 RPrint "系数行列式的值是："; D
1 w4 Y$ U, ~) u( U' D% Zx(n) = a(n, n + 1) / a(n, n)
9 J+ f" i) _; V. g$ o& Z4 zFor k = n - 1 To 1 Step -1 '开始回代
% ]  ~" Z, w6 c: y  EFor j = k + 1 To n
. s0 x8 A8 M; z/ o3 Qm = m + a(k, j) * x(j)
8 V0 e/ t9 Z2 Z( k8 f- _Next j
' r4 w& A$ f$ m, h; Zx(k) = (a(k, n + 1) - m) / a(k, k)
m = 0
  w) A" ^' E$ B/ A# mNext k '结束回代

2 S+ t; S0 g  d# t, l7 u' SPrint "--------------------------------"
& [0 s9 U0 D! x6 E  b0 _: SPrint "方程组的解如下："
6 F8 j4 C/ n! Y* r  @, Y4 Y
' u9 S) U9 Z' W' E0 A0 WFor k = 1 To n
; b  O/ t* @% X' \7 o; mPrint
8 ^! O* @" p  E# V8 ZPrint "X(" & k & ") = " & x(k)
9 t7 Z. }. N/ E# INext k
% L- d. u1 x5 g5 D9 e" C7 WPrint "--------------------------------"
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)
1 [4 o7 k; z: v" ^1 h0 c9 y- {Next j
1 N+ l& `+ E& Y6 w) et = t - a2(i, n + 1)
Print Spc(5); "第" & i & "行："; t
2 K' y% Z' y$ o& u; \$ SPrint
( @2 z, |& k! T2 _1 ANext i
* M3 H, @$ W+ q  @5 c9 B& ?
4 [# B( ]# a! tEnd SubPrivate Sub gauss_Click() '高斯消去法
4 x) F$ H7 Q5 b6 r0 f4 ]  eDim n As Integer, i As Integer, j As Integer, a() As Single, s As String, l() As Single
0 M6 S' o- i" |7 Q+ n& fi = 1: j = 1
" S1 l& t9 B( Y; {' B+ d2 un = 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)
& N; h, Y% s& j" {/ Y$ o) ?0 ~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()
, v5 n3 I: L3 k$ dFor i = 1 To n
! }# l2 S1 O9 N6 @$ R: U: xFor j = 1 To n
a2(i, j) = a(i, j)
9 E" H0 Z( y; [* [8 A. W1 A0 P4 {$ GNext
, k4 K# z2 a4 ~' kNext '将a()的值全部赋给a2()
m = 0
1 Z( H0 n# I0 \' W# g/ ^+ }D = 1
ReDim x(1 To n)
Print "--------------------------------"
- ]1 B* D! O! }# qPrint "您输入的增广矩阵如下："
For i = 1 To n
* R4 P* n: m: y3 y& 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"))
5 g$ ^$ H, n0 `2 E2 a1 sFor j = 1 To n
5 _: K4 ?  d6 f8 Ka(i, j) = Val(Left(s, InStr(s, " ")))
s = Trim(Right(s, (Len(s) - InStr(s, " "))))
Print a(i, j);
Next
" ?" y" B& D1 c3 \* l8 xa(i, n + 1) = Val(s)
/ l& `8 h0 h* ~% ~4 m! NPrint a(i, n + 1);
Print
Next
6 ?' c& o( j7 T& f5 M+ f5 U2 e
For k = 1 To n - 1 '开始消元
If a(k, k) = 0 Then
( ?6 n, {" m, }2 ^" lMsgBox " Sorry！解不出！" + vbCrLf + "原因是：a(" & k & "，" & k & ")=0了！", vbExclamation, "解不出呀！"
/ d4 R, f" }1 |( T! n* b& M$ p, L, \Exit Sub
8 c5 f# G8 H3 LElse
+ m+ i: T, |2 ?; h) IFor i = k + 1 To n
0 l, ^( {" f3 y8 u( c" ol(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)
) N( c. P0 \5 c9 y3 |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！"
2 B( G0 T. q% x, w# u$ E7 }Exit Sub
Else
D = D * a(n, n)
End If
, l, I5 j" S/ k: _  \) a9 _9 BPrint "--------------------------------"
5 u# y" ~6 C: h; NPrint "系数行列式的值是："; D
x(n) = a(n, n + 1) / a(n, n)
& z( u4 U+ u" f% AFor k = n - 1 To 1 Step -1 '开始回代
) n6 W  x8 Y4 y6 j& d# y4 KFor j = k + 1 To n
3 d; ^/ A& C6 \& Em = 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
8 Z* |% @+ @/ H1 g2 U. G! m
8 M9 s6 l& c1 C8 IPrint "--------------------------------"
- }, J& U! w3 h% }4 n* T, k$ ^Print "方程组的解如下："
$ x9 S; v4 b  e9 \
For k = 1 To n
Print
5 s0 Y, |8 T# g9 x- @! CPrint "X(" & k & ") = " & x(k)
7 I# G* y' \/ s4 C1 b0 {2 ]Next k
Print "--------------------------------"
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)
Next j
t = t - a2(i, n + 1)
3 ^% P- S# M0 HPrint Spc(5); "第" & i & "行："; t
Print
8 [' p3 n; _; A( z) l1 j& ]Next i
9 ?7 N% E3 Q7 g" T1 W! h3 m
End Sub

zqyzixin

我也想了解了解！！！先顶一个

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>

ch123en123

下载学习哦