Hello I demand your help . I'm go

[hasnaoui]

Hello
I demand your help .
I'm going to study the accretion-ejection disks using the DVODE-f90 code.
when I compile my example. the calcul stops at T=3,21.

the above message, R1 = 0.3215402479903D+01
At t = 0.3215D+01 y = 0.321568D+01 0.158443D+14 0.193170D+39



Error halt: ISTATE = -1

Can you help me how to integrate my equations system for large T (INFINITY)
you find in the attached files my source file and the dvode_f90 subroutine.

 

[mikrom]

Hello hasnaoui,

Unfortunately, I can't help you with that. Solving such systems requires some experience that I no longer have. I did something like that about 20 years ago - but haven't since.

You didn't even state what the system of 11 differential equations actually looks like. I mean, in order to be able to solve a system of ODEs, I must first have an idea of ​​what kind of system it is, i.e. I must first see it written somewhere - in an article or in a book or somewhere else.

You seem to be trying to solve the system as non-stiff, but most of the time the systems of many ODEs are stiff.
Therefore, if I were you, I would try to use the stiff options - described in the source of dvode_f90_m.f90 from line 213:

https://github.com/valkenburg/vd2020/blob/master/src/vd2010/dvode/dvode_f90_m.f90

Also I would try to explore the stiffoptions.f90 program, to see what stiff options they use:

https://github.com/valkenburg/vd2020/blob/master/src/vd2010/dvode/stiffoptions.f90

 

[xwb]

You are not going to get any help if you demand it.

 

[hasnaoui]

Dear Mikrom (programmer)
Thank you for your responses

Exactly , the 11 differential equations describe the magnetized accretion-ejection disks arround young stellar objects.
These equations are developed by Jonathan Ferreira et al.
I asked him how to resolve these equations for long cordinate space x=z/h. unfortunately, they dont response me.
best regards