Problems with odesolve: The Integral-System may have two solutions but odesolve find the wrong one

Forum|Forum|8 years ago
April 10, 2018
3 replies
2953 views

Hi everybody,

the integral-System I'ld like to solve do have more than one solution. Once odesolve found the right solution, but in the most cases the unphysical soltution is found. Do anybody know this Problem or has a idea how I can tell odesolve, that I'am searching the other solution ?

Big thanks to everybody who can help me.

David

Calculus_Derivatives

F

Fred_Kohlhepp

23-Emerald I

@dahu wrote:

Hi everybody,

the integral-System I'ld like to solve do have more than one solution. Once odesolve found the right solution, but in the most cases the unphysical soltution is found. Do anybody know this Problem or has a idea how I can tell odesolve, that I'am searching the other solution ?

Big thanks to everybody who can help me.

David

The psychics have all abandoned Mathcad! The rest of us mortals will need more information.

D

dahu

Author

1-Visitor

the System of equations is very hughe. I have 5 Integral equations and 2 algebraic equations. Once a time odesolve found the right solution, but in the most cases odesolve finds the wrong solution. So I'm sure, that the System of equations isn't wrong because sometimes odesolve is doing right. But the most of the time it isn't so have you any idea how I can adapt the solve block or anything else to find the right solution everytime ?

W

Werner_E

25-Diamond I

You may add additional appropriate constraints in the solve block and see if that helps.

D

dahu

Author

1-Visitor

I added one initial condition for each equation. Do yuo have any idea how to add more constraints than equations ? I tried this while adding an inequation and it doesn't work

W

Werner_E

25-Diamond I

> Do yuo have any idea how to add more constraints than equations ?

No. We don't see what you are doing, we don't know what kind of ODE you are dealing with. We don't know why you think that is has more than one solution and we don't know what the difference between the correct and the wrong solution may be.

Sorry, but our clairvoyant balls aren't that good 😉

I am not sure if we could help when you show your worksheet, but I am pretty sure we can't without more information. So I would advise that you attach your worksheet if possible. Because of a bug in the foum software you may have to zip it before you ar able to attach it here.