Why Integrator don't update positions?

[Kilver J Campos]

I am new to using PySPH and I noticed that the EPEC and PEC integrators along with the WCSPHStep integration step and the IntegratorSteps that have the "initialize" function do not update the particle positions unless I use the XSPH Correction. Could someone help me to understand these?

Thanks!

[Navaneet Villodi]

If we look at WCSPHStep, we can see that the position is updated as,

d_x[d_idx] = d_x0[d_idx] + dtb2 * d_ax[d_idx]

and it is XSPHCorrection that actually sets d_ax[d_idx].

You could turn off XSPHCorrection as described here. Otherwise, in WCSPHStep, you could change the position to update using the d_u[d_idx] instead of d_ax[d_idx] as,

d_x[d_idx] = d_x0[d_idx] + dtb2 * d_u[d_idx]

y, z and v, w should also be changed similarly for 2D and 3D. 

Cheers 
Navaneet

[Kilver J Campos]

Thank you, I just understand it.