# [Pw_forum] Clarification on idir and awin in average.f90

Dae Kwang Jun jdaekwang at gmail.com
Sat May 21 12:05:29 CEST 2016

```Dear Giovanni Cantele,

You are right. I only looked at the ibrav = 6 in the input file. I should
have paid more attention on how the vacuum was created. I apologize. Also,
the units do appear to be in bohr radii for the output in average.x , i.e.
the first column. I am not sure, however, there are some that say that the
units do not matter in previous posts.

Sincerely,

Dae Kwang Jun

On Thu, May 19, 2016 at 2:36 PM, Dae Kwang Jun <jdaekwang at gmail.com> wrote:

> Dear Giovanni Cantele,
>
> Thank you once again. Also, there seems to be a typo in the example for
> workfunctions in PP/examples. The example states that the workfunction
> calculation is for Al100. However, its idir is set to 3. I think it should
> be Al001 instead. Lastly, I will check the units and put them here later.
>
> Sincerely,
>
> Dae Kwang Jun
>
> On Wed, May 18, 2016 at 4:54 PM, Dae Kwang Jun <jdaekwang at gmail.com>
> wrote:
>
>> Dear all,
>>
>> I would like to make sure whether I am using these parameters correctly.
>> I know that idir is the fixed index which defines the planes of the planar
>> average. I also know that awin is the size of the window for macroscopic
>> averages.
>>
>> However, I do not quite understand what is meant by these two statements.
>> In the tetragonal lattice, it appears that idir=3 takes the average of
>> planes that are perpendicular to the vector that has length = a. And that
>> idir = 1 takes the average of planes that are perpendicular to the vector
>> that has length = c. Is this correct? And does it follow the same logic in
>> other lattices?  Lastly, does awin refer to the area of the plane? Or does
>> it refer to the thickness of the plane?
>>