[Pw_forum] About the spline interpolation for charge density.

[zhaohscas]

Hi all,

I have the following 18*18*18 charge dentity datagrid as follows:

------------------------
         a       b       c       Charge 
       1       1       1       0.430034694385803
       2       1       1       0.433590624875083
       3       1       1       0.444263507693938
       4       1       1       0.461808085757678
       5       1       1       0.485486354576373
       6       1       1       0.514303497336158
      ...     ...      ...  
       18    18       18
------------------------

Where, the a, b, and c is FFT grid point used for sample the charge, and the last column is the corresponding charge density at the FFT grid point defined by crystal vectors: (a,b,c).

I want to make a  spline interpolation to this datagid to get a more dense and smooth charge density datagrid,  I think this should be done by spline interpolation. 

I've read the the source plotrho.f90 of pp.x, and cann't figure it out how can I make my issue solved.  Who can give me some hints?

Sincerely yours, 				
--------------
Hongsheng Zhao <zhaohscas at yahoo.com.cn> 
Xinjiang Technical Institute of Physics and Chemistry
Chinese Academy of Sciences 
GnuPG DSA: 0xD108493
2008-06-18