why is calculated initial value always different from specified one.

Dear All,

I faced one problem in comsol. I specified one non zero initial value for a time dependent physics(tds). after solving, in post processing step, When I plot the average value of dependent variable over time, the value for initial time is always smaller from what I specified in initial value tab in model. it cause problem specially when I coupled it with Matlab. in every large time step, I run comsol, then transfer data to matlab to calculate one thing then pass it to comsol for next time step. for next time , it should use last time value but it is always smaller and it causes a sudden drop in whole profile at beginning of each time step.

any one have any suggestion?

Thanks