<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Hi All,<br><div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div><br></div><div>I would like to access the initial velocity values at each point for subsequent time steps in order to calculate the L2 error of my simulation with time:</div><div><br></div><div>L2_error = sqrt( sum_cells( ( U-U_ini )^2 + ( V-V_ini )^2 )/ sum_cells(U_ini^2+V_ini^2) ).</div><div><br></div><div>I have followed the instructions given in <a href="http://www.paraview.org/pipermail/paraview/2010-November/019461.html">here</a>, and it works fine for one time step. E.g., when these U, V is the final time. Furthermore, I would like to track this value L2_error with time. To do that, I have opened a .vtm file with all the time steps included, and followed the same steps as before. However, after using the Append Attributes filter, the velocity parameters U_t, V_t (the new names I am using) do not update their value with time. I am not sure if I am missing something.</div><div><br></div><div>Thank you very much for your time,</div><div>Henrik</div><div><br></div><div><br></div></div></div><br></body></html>