I have some problems with the parameters section of the code file.

* First*,there are four spring stiffness, km , kg, kt and ktm. My understanding is that km represents side wall normal stiffness and kg is grain’s narmal stiffness, kt is grain grain tangential stiffness , ktm is bottom and top wall’s tangential stiffness, but why the right wall and left wall’s tangential stiffness is not involved .I don’t know if my understanding is correct.

*, I have questions about nuf , nugt and mug. I 'm confused about these parameters.*

**Second***, there’s a code line like that: real r=1e-3;*

**Third**I want to make sure that the parameter, ‘r’, is the conversion factor from millimeter to meter.

*. If I want to build a container, 5 meters long and 0.6 meters high, how should I do? If spacing of each grids is 0.1 millimeter , I shoud modify the code as follows:*

**The last question is about the model**#ifndef lx

#define lx 50001

#endif

#ifndef ly

#define ly 6001

#endif

This operation will result in a huge memory occupied that cannot be calculated, prompt error:core has been dumped.

I noticed that there’s a parameter named scale. What do I need to do to use the parameter, scale, to model without using equal proportion?

Could you please give me some help?