VB与MATLAB通信实现方案一
前言:MATLAB与VB接口,有使用DLL, DDE ,OLE ,ActiveX ,COM 组件等多种方法.
本文介绍的方法:
在VB中通过调用MATLAB的引擎（Engine）接口，使用Windows的OLE或ActiveX通道与MATLAB通信。通过Object．ExecuteMATLAB语句在程序中直接使用MATLAB提供的函数库和图形库。这种方法可以较快地编写出程序；但在调用引擎时，会在后台启动一个MATLAB进程，影响程序运行速度，占用内存。
例子: VB调用MATLAB进行多项式拟合
MATLAB中进行多项式拟合的库函数:
polyfit(x,y,n) 其中x,y为拟合数据，n为拟合多项式的阶数。
例:用最小二乘法拟合数据
x: 0.50 1.00 1.50 2.00 2.50 3.00
y: 1.75 2.45 3.81 4.80 8.00 8.60
x=[0.5,1,1.5,2,2.5,3] y=[1.75,2.45,3.81,4.80,8.00,8.60]
a=polyfit(x,y,2) %用2次多项式拟合上组数据，a为拟合多项式的系数向量
x1=0.5:0.05:3
y1=a(1)*x1.^2+a(2)*x1+a(3)
plot(x1,y1) %画出拟合曲线的图形
hold on %保留上面的图形和坐标，可在该坐标系中继续作图
plot(x,y,‘*’) %用*号的形式画出被拟合的数据图形
VB调用MATLAB进行多项式拟合:
建立VB工程,界面如下:
VB代码:
Option Explicit
Public objmatlab As Object '将MATLAB实例对象定义为公共变量
Private Sub computeorplot(corp As Boolean)
Dim intnum As Integer
Dim intlevel As Integer
Dim x(1 To 100) As Double
Dim y(1 To 100) As Double
Dim strmodel As String
Dim strcom, strcom1, p As String
Dim i As Integer
intnum = Val(Text1.Text) '数据数组
intlevel = Val(Combo1.Text) '多项式阶数
Open App.Path + "/datx" For Output As 1
Print #1, Text3 'X数组
Close 1
Open App.Path + "/daty" For Output As 1
Print #1, Text4 'Y数组
Close 1
Open App.Path + "/datx" For Input As 1
For i = 1 To intnum
Input #1, x(i)
Next i
Close 1
Open App.Path + "/daty" For Input As 1
For i = 1 To intnum
Input #1, y(i)
Next i
Close 1
'定义在MATLAB中要执行的命令
strcom = "n=" & Str(intlevel) & "; x=["
For i = 1 To intnum
strcom = strcom & Str(x(i)) & ""
Next i
strcom = strcom & "]; y=["
For i = 1 To intnum
strcom = strcom & Str(y(i)) & ""
Next i
strcom = strcom & " ];"
If corp Then
strcom = strcom & "p=" & "polyfit(x,y,n)"
Text5 = objmatlab.execute(strcom)
strcom1 = strcom1 & "y=" & "poly2str(p,'*x')"
Text2 = objmatlab.execute(strcom1)
Else
strcom = strcom & "plot(x,y)"
objmatlab.execute (strcom)
End If
End Sub
Private Sub Command1_Click() '计算
Dim bolcorp As Boolean
bolcorp = True '进行多项式拟合
Call computeorplot(bolcorp)
End Sub
Private Sub Command2_Click() '绘图
Dim bolcorp As Boolean
bolcorp = False '绘图
Call computeorplot(bolcorp)
End Sub
Private Sub Command3_Click() '退出
Set objmatlab = Nothing
Unload Me
End Sub
Private Sub Command4_Click() '取消
Text1.Text = ""
Combo1.Text = ""
Text3.Text = ""
Text4.Text = ""
Text5.Text = ""
End Sub
Private Sub Form_Initialize()
Set objmatlab = CreateObject("matlab.application") '创建MATLAB实例
End Sub
按下”绘图”后执行结果:
补充说明:
1. 要在工程中引用:MATLAB Application
2. 使用CreateObject函数创建Matlab对象一般格式:
Dim objmatlab As Object
Set objmatlab = CreateObject("matlab.application")
3. 自动化之Execute方法:
Execute方法将一个命令字符串作为变量并返回一个字符串
‘Dim strcom As String
Text1 = objmatlab.execute(strcom)
Edited by Guassfans 2007-07-19
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