Learning Forum

[ll00023]

this UDF code is for computing the melting index along a particle trajectory.

this code has been tested in 2d and 3d cases in the DPM model.

what I tried to achieve is by using this code to obtain the particle locations of 10 particles with respect to time.

based on my understanding, this code just records ONE particle location and writes them into a file (melting_output).

I copied the code and pasted it into txt file. I hooked it up in DPM model.

the code could be compiled but when DPM iterates, then I this SIGSEGV error.

I used a linux server to run fluent case.

I searched it; it is said this error shows 

"SIGSEV tends to be network related, but may be triggered by something else in the solver: it's not an error we can diagnose as such. What did the TUI show just above all of that lot? That text may be more useful." from Rob.

the model works before using this code.

 

how to debug this kind of error?

Thank you.

[Rob]

I assume you have set a scalar up to store the data? 

However, "malloc" is Memory allocation so check the amount of RAM you have available. 

[ll00023]

This is a 2d case; not much Mem is used. the memory should be enough.

[ll00023]

Yes, I use a scalar to store particle data.

[Rob]

OK, so the code without trying to find the particle location works? Look at what you changed/added and see what that interacts with. Turn off the new stuff and slowly turn it on again, ie use a constant rather than an equation to do whatever etc.  

[ll00023]

I will test the example code accordingly and post the result later.  Thank you.

[ll00023]

this solves the issue.

[Rob]

Yes, you need to set the UDM memory allocations or things go wrong - I thought you were using a Scalar though? 

[ll00023]

I am using this macro define_dpm_scalar_update. is this a scalar?

[Rob]

Yes, but I also don't know what you're doing with it! 

[ll00023]

the debugging process is confusing to me, since what I know is just some basic knowledge. I could not be able to describe it clearly. I even missed this when I went through some online tutorials. and UDF manual just mentions hooking UDF. I learnt it bit by bit. Thank you for your help in this debugging process.

Lei

[Rob]

They're not easy - I know the basics and rely on colleagues for anything complicated.