Some problems about the grid point of pot.cube file in the EXTERNAL_POTENTIAL subsection

[jts2t... at gmail.com]

Hi Nico, 

Thanks for your patience and detailed reply! It's pretty useful for me! 
I'll try it.

在 2017年12月1日星期五 UTC+8下午6:31:14，Nico Holmberg写道：
>
> Hi,
>
> You need to supply a cube file that contains as many grid points as the 
> grid that holds the real space electron density in your simulation system 
> (depends on the PW_CUTOFF and cell size). You can check the size of this 
> grid by turning on the print key FORCE_EVAL/PRINT/GRID_INFORMATION (see 
> example below). When you print out a cube file, unless you explicitly 
> specify otherwise, only every second value along each axis is printed out 
> (keyword STRIDE). You need to take this into account when you supply a file 
> for READ_FROM_CUBE, because as far as I understand no 
> interpolation/extrapolation from tighter/looser grids is possible.
>
> An example output is given below. In this case, the grid contains 350^3 
> points at a planewave cutoff of 500 Ry. So to summarize, if your system 
> contains 54 data points along each direction (at STRIDE 1), then you need 
> to provide a cube with 54^3 grid points. You need a larger cube file with 
> (2*54)^3 grid points if you printed out the cube file with STRIDE 2.
>
>  PW_GRID| Information for grid 
> number                                          1
>  PW_GRID| Grid distributed over                                   192 
> processors
>  PW_GRID| Real space group dimensions                                   
> 192    1
>  PW_GRID| the grid is 
> blocked:                                                NO
>  PW_GRID| Cutoff [a.u.]                                                    
> 250.0
>  PW_GRID| spherical 
> cutoff:                                                   NO
>  PW_GRID|   Bounds   1           -175     174                
> Points:         350
>  PW_GRID|   Bounds   2           -175     174                
> Points:         350
>  PW_GRID|   Bounds   3           -175     174                
> Points:         350
>  PW_GRID| Volume element (a.u.^3)  0.2459E-02     Volume (a.u.^3)    
> 105442.7279
>  PW_GRID| Grid span                                                    
> FULLSPACE
>  PW_GRID|   Distribution                         Average         
> Max         Min
>  PW_GRID|   G-Vectors                           223307.3      223650      
> 223300
>  PW_GRID|   G-Rays                                 638.0         
> 639         638
>  PW_GRID|   Real Space Points                   223307.3      245000      
> 122500
>
>  RS_GRID| Information for grid 
> number                                          1
>  RS_GRID|   Bounds   1           -175     174                
> Points:         350
>  RS_GRID|   Bounds   2           -175     174                
> Points:         350
>  RS_GRID|   Bounds   3           -175     174                
> Points:         350
>  RS_GRID| Real space distribution over                                  4 
> groups
>  RS_GRID| Real space distribution along 
> direction                              1
>  RS_GRID| Border 
> size                                                         29
>  RS_GRID| Real space distribution over                                  6 
> groups
>  RS_GRID| Real space distribution along 
> direction                              2
>  RS_GRID| Border 
> size                                                         29
>  RS_GRID| Real space distribution over                                  8 
> groups
>  RS_GRID| Real space distribution along 
> direction                              3
>  RS_GRID| Border 
> size                                                         29
>  RS_GRID|   Distribution                         Average         
> Max         Min
>  RS_GRID|   Planes                                 145.5         
> 146         145
>  RS_GRID|   Distribution                         Average         
> Max         Min
>  RS_GRID|   Planes                                 116.3         
> 117         116
>  RS_GRID|   Distribution                         Average         
> Max         Min
>  RS_GRID|   Planes                                 101.8         
> 102         101
>
> BR, 
>
> Nico
>
>
> perjantai 1. joulukuuta 2017 11.19.13 UTC+2 jts2... at gmail.com kirjoitti:
>>
>> Hi everyone,
>>
>> I have asked several questions about the same subject. Until yesterday, I 
>> have figured out the meaning of the *.cube file generated by CP2K. 
>> What I want to do is to add potential to my simulation system, but the 
>> potential is calculated from Poisson equation using finite element method.
>> Hence I only have grid point values of the potential. 
>>
>> So the solution is adding the potential from pot.cube file using 
>> READ_FROM_CUBE option. I will try this in a simple simulation to figure the 
>> structure. 
>> The simulation box in my simulation is a cube, whose length of a side is 
>> 12.4138 (Angstrom, I think). And from the *.cube file I know the length 
>> of the 
>> vector along x, y and z direction is 0.434420(Angstrom, maybe). What's 
>> more, the number of data points along each direction is 54.
>>
>> Now I need to supply the pot.cube file to CP2K. I wonder how many grid 
>> point value should be given?
>> (54*12.4138 / 0.434420) ^3 ?
>>
>> I major in mathematic, so the easy thing for you may be a problem for me.
>>
>> Thanks for your reply !
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20171201/94207eb8/attachment.htm>