Hi everyone, I currently working on a project and would like to do the following task and need some guidance. (1) Read an .fld file. (2) Load it into vector fields into expansions (exp_u, exp_v, exp_w) (3) Loop through each element in the mesh and do some processing in it and store the result in a new expansion. I have a problem in step (3). I am able loop through each expansion but unable to understand how should I retrieve coefficients for each element. Array<OneD,NekDouble> gcoeff = exp_u->GetCoeffs() - This gets me the coefficients of whole expansion. How do I match coefficients which belong to each element. These two statements used in the code seem to reorder the coefficients in the expansion, Can someone explain what they are doing. Exp_u->GlobalToLocal() Exp_u->LocalToGlobal() Would any of these functions reorder coefficients elementwise. So that I use access element[i]'s coefficients as gcoeff[I*numOfCoeffPerEle]. Ashok.