[QE-users] Comparison of k_points for two different inputs of BCC structure

Xin Jin xin.tlg.jin at outlook.com
Mon Oct 31 12:58:30 CET 2022


Hello Krishnendu,

I saw there are k-points given by the output of pw.x:

number of k points=    10  Methfessel-Paxton smearing, width (Ry)= 0.0600
                        cart. coord. in units 2pi/alat
         k(    1) = (   0.0000000   0.0000000   0.0000000), wk = 0.0312500
         k(    2) = (   0.0000000   0.0000000   0.0833333), wk = 0.1875000
         k(    3) = (   0.0000000   0.0000000  -0.1666667), wk = 0.0937500
         k(    4) = (   0.0000000   0.0833333   0.0833333), wk = 0.3750000
         k(    5) = (   0.0000000   0.0833333  -0.1666667), wk = 0.3750000
         k(    6) = (   0.0000000  -0.1666667  -0.1666667), wk = 0.0937500
         k(    7) = (   0.0833333   0.0833333   0.0833333), wk = 0.2500000
         k(    8) = (   0.0833333   0.0833333  -0.1666667), wk = 0.3750000
         k(    9) = (   0.0833333  -0.1666667  -0.1666667), wk = 0.1875000
         k(   10) = (  -0.1666667  -0.1666667  -0.1666667), wk = 0.0312500



But I am not sure how to exactly compare to the k-points generated by you.
However if you are interested, I think you can generate the list of 
k-points from my input. of My input is at the end of the email.

Thank you.

Best regards,
Xin

On 31/10/2022 12:24, KRISHNENDU MUKHERJEE wrote:
>
> Hello Xin,
>
> Thank you for your reply. I have made a new thread. Below is the 
> k-points obtained from kpoints.x for BCC Bravais Lattice, for a 4 4 4 
> 0 0 0 mesh, considering the 48 symmetries. I hope this will be the 
> same for the case with calculations for ibrav=3, with BCC primitive 
> cell with one atom per cell.
> 8 (=number of k_points)
>
>     1   0.0000000  0.0000000  0.0000000   1.00
>     2   0.2500000  0.0000000  0.2500000  12.00
>     3   0.5000000  0.0000000  0.5000000   6.00
>     4   0.2500000  0.2500000  0.5000000  24.00
>     5   0.0000000  0.0000000  0.5000000   6.00
>     6   0.2500000  0.0000000  0.7500000  12.00
>     7  -0.5000000  0.5000000  0.5000000   2.00
>     8   0.0000000  0.0000000  1.0000000   1.00
>
>
> Now let us compare with the k_points that were used in your 
> calculation when a BCC supercell consisting of BCC Unit Cells is used 
> as input with ibrav=0. So, I request you if you can kindly post the 
> k_points considered in your calculation. Also you may kindly include 
> your input script once more so that later on somebody can follow the 
> discussion.
>
> Thanking you,
> Best regards,
> Krishnendu
>
>
> ------------------------------------------------------------------------
> *From: *"xin tlg jin" <xin.tlg.jin at outlook.com>
> *To: *users at lists.quantum-espresso.org
> *Cc: *"KRISHNENDU MUKHERJEE" <krishnendu at nmlindia.org>
> *Sent: *Monday, October 31, 2022 12:28:24 PM
> *Subject: *Re: [QE-users] Parallel computing of QE7.1 vc-relax crashes 
> when using large number of processors
>
> Hello Krishnendu,
>
> Thank you for the message
> Yes, we can start a separate thread. I didn't realize that there could 
> be such a problem.
> Actually, the reason that I use ibrav=0 for BCC W is that I want to 
> put some interstitials inside if the program works.
>
> Best regards,
> Xin
>
>
> On 30/10/2022 05:35, KRISHNENDU MUKHERJEE wrote:
>
>
>     Dear Xin Jin,
>
>      Sorry that I have another matter to discuss. If you wish we may
>     start a separate thread on the subject I am eager to discuss. I
>     have some concern about your script. If you want to do calculation
>     for BCC W you may need to use ibrav=3. Note that for ibrav=3 the
>     (primitive) lattice vectors are in the form:
>
>     ibrav=3          cubic I (bcc)
>           v1 = (a/2)(1,1,1),  v2 = (a/2)(-1,1,1),  v3 = (a/2)(-1,-1,1)
>     which is inbuilt in QE (so that you need not input
>     CELL_PARAMETERS) and you only need to put an atom in the position
>     0.00 0.00 0.00.
>     With those input QE determines the k_points for BCC Bravais Lattice.
>
>     You have input the atomic positions in terms of supercell made of
>     BCC unit cell. And you have put ibrav=0. With those input I am
>     afraid most probably the k_points generated would be that of a
>     Simple Cubic structure.
>     What we can do is next week I would generate the k_points for BCC
>     with a mesh of 4 4 4 0 0 0 and post it. And you can see whether it
>     is matching with the k_points considered in your calculation and
>     discuss further.
>
>     Thank you,
>     Best regards,
>     Krishnendu
>
>     ------------------------------------------------------------------------------------------------------------------------------------------
>
>     Xin Jin wrote on 28/Oct/2022
>
>
>     Dear Quantum Espresso Forum,
>
>     I encountered a problem related to the parallel computing using QE7.1
>     for vc-relax.
>
>     I was trying to perform a vc-relax for a 3*3*3 BCC tungsten super
>     cell.
>     The code works fine for non-parallel computing, also works fine for
>     parallel computing if the number of processors is smaller than 10.
>
>     However, if the number of processors is larger than 10, I will get
>     following MPI error:
>     /*** An error occurred in MPI_Comm_free//
>     //*** reported by process [3585895498,2]//
>     //*** on communicator MPI_COMM_WORLD//
>     //*** MPI_ERR_COMM: invalid communicator//
>     //*** MPI_ERRORS_ARE_FATAL (processes in this communicator will
>     now abort,//
>     //***    and potentially your MPI job)/
>
>     For parallel computing, I am using /OpenMPI/3.1.4-gcccuda/. (In
>     addition, it seems that If I use OpenMPI V4, the simulation speed
>     will
>     be much slower than that of V3.)
>
>     Another thing is that, if I decrease the size of the supper cell, for
>     example to 2*2*2, then there is no problem in the parallel computing
>     even if I use more than 30 processors.
>
>     Could you help me look at this problem, please?
>
>     The input for QE can be found below.
>
>     Thank you in advance!
>
>     Xin Jin
>
>     /&control//
>     //
>     //    calculation='vc-relax' //
>     //    restart_mode='from_scratch', //
>     //    prefix='W_relax', //
>     //    pseudo_dir="../../PP_files",//
>     //    outdir='./'//
>     //
>     // ///
>     ////
>     //
>     // &system//
>     //    ibrav= 0, //
>     //    celldm(1)=5.972,//
>     //    nat=  54, //
>     //    ntyp= 1,//
>     //    ecutwfc = 50,//
>     //    ecutrho = 500,//
>     //    occupations='smearing', smearing='mp', degauss=0.06//
>     // ///
>     //
>     // &electrons//
>     //    diagonalization='david',//
>     //    conv_thr =  1.0d-8,//
>     //    mixing_beta = 0.5,//
>     // ///
>     ////
>     // &ions//
>     // ///
>     //
>     // &cell//
>     //    press = 0.0,//
>     // ///
>     ////
>     //ATOMIC_SPECIES//
>     // W  183.84 W.pbe-spn-kjpaw_psl.1.0.0.UPF//
>     ////
>     //CELL_PARAMETERS {alat}//
>     //   3.0  0.0  0.0//
>     //   0.0  3.0  0.0//
>     //   0.0  0.0  3.0 //
>     ////
>     //ATOMIC_POSITIONS {alat}//
>     //W 0.00000 0.00000 0.00000//
>     //W 0.50000 0.50000 0.50000//
>     //W 1.00000 0.00000 0.00000//
>     //W 1.50000 0.50000 0.50000//
>     //W 2.00000 0.00000 0.00000//
>     //W 2.50000 0.50000 0.50000//
>     //W 0.00000 1.00000 0.00000//
>     //W 0.50000 1.50000 0.50000//
>     //W 1.00000 1.00000 0.00000//
>     //W 1.50000 1.50000 0.50000//
>     //W 2.00000 1.00000 0.00000//
>     //W 2.50000 1.50000 0.50000//
>     //W 0.00000 2.00000 0.00000//
>     //W 0.50000 2.50000 0.50000//
>     //W 1.00000 2.00000 0.00000//
>     //W 1.50000 2.50000 0.50000//
>     //W 2.00000 2.00000 0.00000//
>     //W 2.50000 2.50000 0.50000//
>     //W 0.00000 0.00000 1.00000//
>     //W 0.50000 0.50000 1.50000//
>     //W 1.00000 0.00000 1.00000//
>     //W 1.50000 0.50000 1.50000//
>     //W 2.00000 0.00000 1.00000//
>     //W 2.50000 0.50000 1.50000//
>     //W 0.00000 1.00000 1.00000//
>     //W 0.50000 1.50000 1.50000//
>     //W 1.00000 1.00000 1.00000//
>     //W 1.50000 1.50000 1.50000//
>     //W 2.00000 1.00000 1.00000//
>     //W 2.50000 1.50000 1.50000//
>     //W 0.00000 2.00000 1.00000//
>     //W 0.50000 2.50000 1.50000//
>     //W 1.00000 2.00000 1.00000//
>     //W 1.50000 2.50000 1.50000//
>     //W 2.00000 2.00000 1.00000//
>     //W 2.50000 2.50000 1.50000//
>     //W 0.00000 0.00000 2.00000//
>     //W 0.50000 0.50000 2.50000//
>     //W 1.00000 0.00000 2.00000//
>     //W 1.50000 0.50000 2.50000//
>     //W 2.00000 0.00000 2.00000//
>     //W 2.50000 0.50000 2.50000//
>     //W 0.00000 1.00000 2.00000//
>     //W 0.50000 1.50000 2.50000//
>     //W 1.00000 1.00000 2.00000//
>     //W 1.50000 1.50000 2.50000//
>     //W 2.00000 1.00000 2.00000//
>     //W 2.50000 1.50000 2.50000//
>     //W 0.00000 2.00000 2.00000//
>     //W 0.50000 2.50000 2.50000//
>     //W 1.00000 2.00000 2.00000//
>     //W 1.50000 2.50000 2.50000//
>     //W 2.00000 2.00000 2.00000//
>     //W 2.50000 2.50000 2.50000//
>     //
>     //K_POINTS {automatic}//
>     //4 4 4 0 0 0//
>     /
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