improvement on the output of 2nd colomn of BAND_1.dat: list of X for ploting band strucuture

[QG-phy]

Background

when I use the KPT in the screenshot to perform the band structure calculations, I want to get the bands along the k-path of G-X-U | K-G ... . The whole K-path is not continuous.

The 2nd column of BADN-1.dat behaves as the list of X in plotting the band structure. But here it shows an step change of the x value, which should not be there for ploting bands.

Describe the solution you'd like

just modify the mapping from the K-path to the x-list， making the x-list continuous.

Task list only for developers

• Notice possible changes of behavior
• Explain the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi

Notice Possible Changes of Behavior (Reminder only for developers)

No response

Notice any changes of core modules (Reminder only for developers)

No response

Notice Possible Changes of Core Modules (Reminder only for developers)

No response

Additional Context

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Task list for Issue attackers (only for developers)

• Review and understand the proposed feature and its importance.
• Research on the existing solutions and relevant research articles/resources.
• Discuss with the team to evaluate the feasibility of implementing the feature.
• Create a design document outlining the proposed solution and implementation details.
• Get feedback from the team on the design document.
• Develop the feature following the agreed design.
• Write unit tests and integration tests for the feature.
• Update the documentation to include the new feature.
• Perform code review and address any issues.
• Merge the feature into the main branch.
• Monitor for any issues or bugs reported by users after the feature is released.
• Address any issues or bugs reported by users and continuously improve the feature.

[kirk0830]

Hi, I have carefully checked both the case you provided and corresponding source code details. I find the No. 61 and 62 kpoints are not identical, they seem just have identical energy spectra. To verify this, I run the example in examples/band/lcao_Si2, with a little change in KLINES file:
original:

K_POINTS
6
Line
0.5 0.0 0.5 20
0.0 0.0 0.0 20
0.5 0.5 0.5 20
0.5 0.25 0.75 20
0.375 0.375 0.75 20
0.0 0.0 0.0 1

to-test:

K_POINTS
7
Line
0.5 0.0 0.5 20
0.0 0.0 0.0 20
0.5 0.5 0.5 20
0.0 0.0 0.0 1
0.5 0.25 0.75 20
0.375 0.375 0.75 20
0.0 0.0 0.0 1

Therefore I can also check what happened to No.61 and No.62 kpoints:
kpoints file:

...
      61   0.00000000   0.00000000   0.00000000 1.0000
      62   0.50000000   0.25000000   0.75000000 1.0000
...

BAND_1.dat

...
  61   2.73205081  -5.33892624   6.68534236   6.68534236   6.68534236   9.41056995   9.41056995   9.41056995  10.29720579
  62   3.85008480  -0.96935813  -0.96935813   2.47467459   2.47467459  11.54795528  11.54795528  12.20365346  12.20365346
...

Thus the problem relies on distinguish the user demand that once a kpoint is specified with number "1", should ABACUS consider it is a new segment of kline.

I think it is a newly required feature and will be supported in recent PR(s).