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.