Do While Variations

[Philosophaie]

Invalid procedure call or argument

I have heard that much during the past week.

Here is my code:

    Pi = Application.WorksheetFunction.Pi
    MA = Cells(4, 3)
    e = Cells(4, 4)
    EA = 100
    diff = 0.02
    Do While (diff > 0.00001 Or diff < -0.00001)
        diff = (EA - 180 / Pi * e * Math.Sin(EA * Pi / 180) - MA) / (180 / Pi * (1 - e * Math.Cos(EA * Pi / 180)))
        EA = EA + diff
    Loop
    EA = EA - 360 * Int(EA / 360)

To not here the infernal "Invalid procedure call or argument" I can set the "Do While" to do:

Do While diff>0.0001 or
 Do While diff<0.0001

but that is not what the equation says. diff must be but all give the error above:

 Do While (diff>0.0001 or diff<-0.0001)  or
 Do While Math.Abs(diff)>0.0001   or
 Do While Math.Sqr((diff)^(2))>0.0001

Please can someone show me where I am going wrong.

 

[JoeMo]

What are the values of MA and e when you get the error?

 

[Eric W]

It's hard to tell because you don't tell us what's in cells C4 and D4, but I suspect you're getting a division by zero. Check your formula.

 

[Philosophaie]

MA=150
e=0.0123

 

[Eric W]

Not a division by zero, but the same type of thing. Your value of EA grows very large, -5*10^20, which is too big for the sin and cos functions. By the looks of your code, you're expecting some function to converge and are using diff to decide when the value is close enough. Instead it's diverging. diff is increasing monotonically. You'll need to examine your basic logic. I looked at the code and couldn't figure out what exactly you're trying to do.