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1

General Questions and Answers / Distinguishing branches of phonon dispersion exported to .txt file

« on: May 9, 2017, 07:56 »

Dear all,

I calculated phonon dispersion of graphene and exported data to .txt file. (attached .txt file)
In the .txt file, data are separated and labeled as "Band0"~"Band5", and I plotted them. (attached .jpg file)
In the graph, 6 different colors are corresponding to "Band0"~"Band5".

However, I want the data points to be distinguished by phonon modes (LA,TA,ZA,LO,TO,ZO),
so that 6 different colors represent each phonon mode and phonon branches with different colors can cross each other.

How can I do that?
Any advice would be appreciated.

2

General Questions and Answers / Error message: "unknown software exception" when using larger # of processors

« on: February 17, 2017, 05:28 »

Dear All,

My calculation is optimizing the structure of graphene, and "the number of k points" are 85.
I'm trying to compare the time taken for calculation when "the number of processors" are 5 and 17 (I have 28 processors in total).

I got the calculation result when using 5 processors,
but I got the error message ".... unknown software exception (0xc000417)......" when using 17 processors.
(please see the attached img file. Error message is written in Korean partially, but I hope you can guess.)

I do not get this error message when the number of processors is below 8,
but when the number of processor is more than 8, say "N" number of processors,
N-8 number of atkpython.exe is forcibly closed about 1 minute after starting calculation.

Please help me solving this problem.
Thank you in advance.

3

General Questions and Answers / Change in "number of processors per kpoint" doesn't seem to be applied.

« on: February 16, 2017, 10:39 »

Dear all,

I'm a quite new to VNL-ATK and I'm trying to optimize the structure of graphene.
I changed "number of processor per kpoint" from default value to 4 (using "scriptor" or "editor") and checked log file after calculation.
But in the log file, I got the warning message like below,

+------------------------------------------------------------------------------+
| DiagonalizationSolver parallelization report.                                |
+------------------------------------------------------------------------------+
| Total number of processes: 4                                                 |
| Total number of k-points: 85                                                 |
| Processes per k-point: 1                                                     |
| Number of process groups: 4                                                  |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| WARNING: Sub-optimal distribution of processes over k-points.                |
| For optimal performance make sure the number of processes is                 |
| a multiple of the number of k-points times processes_per_kpoint.             |
| 3 process(es) have fewer k-points assigned than others                       |
| and will be partially idle.                                                  |
+------------------------------------------------------------------------------+
| WARNING: Sub-optimal process distribution for the DiagonalizationSolver.     |
| Number of processes per k-point has been adapted for better performance.     |
| For an optimal process distribution, use 4 MPI process(es),                  |
| and set processes_per_kpoint=1                                               |
+------------------------------------------------------------------------------+

Calculation is finished anyway, but the changed value of "number of processors per kpoint" is not reflected.
Is this a bug or am I making mistake?
Any help or comments would be greatly appreciated.