Hello,

Does anyone know how to solve the below problem during screening calculation using the gwcomp technique?

''gwcompleteness.F90:149:WARNING

Number of G1-G2 pairs outside the G-sphere for Wfns = 396572"

It is suggested to use either larger ecutwfn or smaller ecuteps to get rid of that. However, my ecuteps is 5 Ry already small and ecutwfn is the default of ecut which cannot be larger. Any idea?

Best,

xW

## G1-G2 pairs outside the G-sphere in screening calculation [SOLVED]

**Moderators:** gmatteo, bruneval, rigna

### Re: G1-G2 pairs outside the G-sphere in screening calculatio

I also tried to increase ecutwfn to 40 and 50 Ha, the number of G1-G2 pairs did decrease, but still a huge number, about 1e+5. Anything else I can try?

### Re: G1-G2 pairs outside the G-sphere in screening calculatio [SOLVED]

This problem may be due to the large anisotropy of my system. I have a very long crystal length.

wxiaom86 wrote:Hello,

Does anyone know how to solve the below problem during screening calculation using the gwcomp technique?

''gwcompleteness.F90:149:WARNING

Number of G1-G2 pairs outside the G-sphere for Wfns = 396572"

It is suggested to use either larger ecutwfn or smaller ecuteps to get rid of that. However, my ecuteps is 5 Ry already small and ecutwfn is the default of ecut which cannot be larger. Any idea?

Best,

xW

### Re: G1-G2 pairs outside the G-sphere in screening calculatio

1 year too late maybe:

Getting G1-G2 vectors outside the G-sphere for wfn is fine I think, but the question is whether the summation in the gwcomp method is converged (when summing over G vectors inside the G-sphere). I just made a post that might affect the results that you're getting.

viewtopic.php?f=11&t=4071

Best

Yuanxi Wang

Getting G1-G2 vectors outside the G-sphere for wfn is fine I think, but the question is whether the summation in the gwcomp method is converged (when summing over G vectors inside the G-sphere). I just made a post that might affect the results that you're getting.

viewtopic.php?f=11&t=4071

Best

Yuanxi Wang

- hameed1987
**Posts:**33**Joined:**Sat Jun 22, 2019 12:45 pm**Location:**The UK

### Re: G1-G2 pairs outside the G-sphere in screening calculation

Dear wxiaom86

My problem is similar to yours. Please tell me how did you solve it ? please see below my error

--- !ERROR

src_file: kgindex.F90

src_line: 110

mpi_rank: 2

message: |

The G-vector with ig: 4436 falls outside the FFT box.

My problem is similar to yours. Please tell me how did you solve it ? please see below my error

--- !ERROR

src_file: kgindex.F90

src_line: 110

mpi_rank: 2

message: |

The G-vector with ig: 4436 falls outside the FFT box.