[QE-users] Counting Basis Functions

[Ben Comer]

Thanks for this! I'm not familiar with how this translates into basis 
functions. How many total basis functions does this result in, and how 
would I calculate the number? is it just 499x199x55 = 5,461,555?

On 2/19/20 12:16 PM, Stefano de Gironcoli wrote:
> On 19/02/20 17:58, Ben Comer wrote:
>> sticks:   dense  smooth     PW G-vecs:    dense smooth      PW
>>      Sum         499     199        55                     51837 
>> 13151      1677 
>
> there are 51837 G vectors such that ekin < ecutrho   ... this is used 
> to expand the density
>
> there are 131151 G-vectorse such that ekin < ecutwfc*4 ... this is 
> used to apply the potential on a wfc
>
> there are  1677 G-vectrose such that ekin < ecutwfc ...  this used to 
> expand the wfcs
>
> -
>
> sticks refers to the fact that G-vectors are organized in z-oriented 
> sticks. this affects the fft distribution
>
>  499 non empty sticks in the FFT up to ecutrho, 199 non empty sticks 
> in the FFT up to ecutwfc*4, 55 non-empty sticks in the FFT up to Ecutwfc
>
>
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