Post processing data

Submitted by Gulniamat on Fri, 07/22/2016 - 12:48

hello every one ....!
Few days ago i posted my problem about the same topic but no one replied me, i thought that may be my friends could not understand my problem so i am reposting my problem.
I am new user of LIGGGHTS, i am actually studying mixing of glass particles in a cylindrical mixer. i have completed my simulations in LIGGGHTS, paraview shows good mixing. Now i have zero idea about what to do further and how to draw graphs etc. how can i make analysis of data ?? i have copied a portion from the output file of particular time step and attached here just to assist you people to understand what i am actually asking. In the attached file i have 3 velocity components and 3 forces for each particle, as i have 27000 particle so i got 27000 rows as well (but i copied only few rows here) . now how i can calculate the mean velocity and average inter particles force for of all particles at particular time step e.g at step # 160000. i used 27000 particles and total runs are 800000 ,time step that i used is 0.00005 . if i want to draw graph between mean velocity and time then obviously i will be needed mean velocity at different time interval . some one told me to use matlab but i dont have the idea, suppose i am using matlab or excel to draw graphs but what will be my input data???? plzzzzzzzzzz guide me .i am stuck here. its just two week left in study and i have to complete all this in these two weeks.

AttachmentSize
File post1.odt84.38 KB

Forums:

Westbrink | Fri, 07/22/2016 - 13:09

Hi Gulniamat,

I hope I can help you a little bit. I checked the manual and I think, I found a proper solution for your problem.
If you want to get an average of the velocity vectors of all particles, you can use the compute reduce command. With it, it is possible to calculate the average of an attribute for all particles. Please check the manual for this command.

To output this value, you can use the fix print command and save it into a CSV or txt file.
This data can be read by Excel, Matlab etc and there you are able to create graphs.

Regards,
Westbrink

Gulniamat | Sat, 07/23/2016 - 17:36

Thanks Westbrink
just tell me one thing as i have done all the simulations,is it possible to use this command now??

Westbrink | Mon, 07/25/2016 - 07:38

No, that is not possible.

But you have all your dump files and with some Excel-VBA or Matlab programming it is possible to read out meaningful data and averages it afterwards.

Regards,
Westbrink