[Wannier] Unable_to_satisfy_B1

Jonathan Yates jonathan.yates at materials.ox.ac.uk
Wed Oct 11 22:14:25 CEST 2017


Dear Satya,

Can you post your win file please - once we see this I suspect the problem will be easy to solve.

Jonathan


On 11 Oct 2017, at 18:01, Satyananda Chab <csatya11 at gmail.com> wrote:

> Dear experts & developers,
> 
> I am working on a monolayer transition-metal trichalcogenide semiconductor
> with a vacuum of about 20 \AA in the z-direction and I am trying to get MLWF
> for the same. However the code throws the following error saying that it is 
> unable to satisfy B1 with any of the first  12 shells. I try changing the search_shells
> parameters in the .win file as suggested by the code which does not help. I try
> changing the tolerance which also goes in vain. I request the experts and developers 
> in this forum to point out the probable reason(s) for the error. Help acknowledge
> thankfully in advance.
> 
> 
>                 satya
> 
> 
>                                 ------------
>                                 K-POINT GRID
>                                 ------------
>   
>              Grid size = 11 x 11 x  1      Total points =  121
> 
> *---------------------------------- MAIN ------------------------------------*
>  |  Number of Wannier Functions               :                48             |
>  |  Number of input Bloch states              :                48             |
>  |  Output verbosity (1=low, 5=high)          :                 1             |
>  |  Timing Level (1=low, 5=high)              :                 1             |
>  |  Optimisation (0=memory, 3=speed)          :                 3             |
>  |  Length Unit                               :               Ang             |
>  |  Post-processing setup (write *.nnkp)      :                 F             |
>  |  Using Gamma-only branch of algorithms     :                 F             |
>  *----------------------------------------------------------------------------*
>  *------------------------------- WANNIERISE ---------------------------------*
>  |  Total number of iterations                :               100             |
>  |  Number of CG steps before reset           :                 5             |
>  |  Trial step length for line search         :             2.000             |
>  |  Convergence tolerence                     :         0.100E-09             |
>  |  Convergence window                        :                -1             |
>  |  Iterations between writing output         :                 1             |
>  |  Iterations between backing up to disk     :               100             |
>  |  Write r^2_nm to file                      :                 F             |
>  |  Write xyz WF centres to file              :                 F             |
>  |  Use guiding centre to control phases      :                 F             |
>  *----------------------------------------------------------------------------*
>  Time to read parameters        0.004 (sec)
> 
>  *---------------------------------- K-MESH ----------------------------------*
>  +----------------------------------------------------------------------------+
>  |                    Distance to Nearest-Neighbour Shells                    |
>  |                    ------------------------------------                    |
>  |          Shell             Distance (Ang^-1)          Multiplicity         |
>  |          -----             -----------------          ------------         |
>  |             1                   0.096882                      2            |
>  |             2                   0.096887                      4            |
>  |             3                   0.167807                      4            |
>  |             4                   0.167815                      2            |
>  |             5                   0.193764                      2            |
>  |             6                   0.193773                      4            |
>  |             7                   0.256327                      4            |
>  |             8                   0.256332                      4            |
>  |             9                   0.256341                      4            |
>  |            10                   0.279157                      2            |
>  |            11                   0.290645                      2            |
>  |            12                   0.290660                      4            |
>  +----------------------------------------------------------------------------+
>  | The b-vectors are chosen automatically                                     |
>  | SVD found small singular value, Rejecting this shell and trying the next   |
>  | SVD found small singular value, Rejecting this shell and trying the next   |
>  | SVD found small singular value, Rejecting this shell and trying the next   |
>  | SVD found small singular value, Rejecting this shell and trying the next   |
>  | SVD found small singular value, Rejecting this shell and trying the next   |
>   
>  Unable to satisfy B1 with any of the first  12 shells
>  Your cell might be very long, or you may have an irregular MP grid
>  Try increasing the parameter search_shells in the win file (default=12)
>   
>  Exiting.......
>  kmesh_get_automatic
> 
> 
> -- 
> Satyananda Chabungbam  
> PostDoc Fellow
> Harish-Chandra Research Institute
> Allahabad-211019
> India
> 
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