I have a confusion about the defination of the variables for DEM in GPU. In file JSphGpu.h, the variables for DEM were defined using "float4 *DemDatag". But the there are only 4 variables, mass, (1-poisson^2)/young, kfric, restitu, respectively. If I wanted to add 2 variables or more variables, how can I realize it? Looking forward to your aid.