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Q1] In part A, it is not detecting the co-ordinates of the high symmetry K-points from the file, why? (part A shows the part of the OUTCAR file mentioning KPOINTS) (KPOINTS file in .rar file attached)

Q2] In part B, it is not detecting the whole high symmetry path but the partial one Ex: actual path is (g-X-M-g-Z-R-A-Z X-R M-A) but in outcar it shows (g-X-M-g-Z-R-A) , why?

A]
KPOINTS: k-points for bandstructure g-M-x-g-Z-A

Interpolating k-points between supplied coordinates.

Line segments in fractional coordinates (reciprocal lattice):

Generated 100 points on each line segment, for a total of 0 k-points:

Following reciprocal coordinates:
Coordinates Weight

Following cartesian coordinates:
Coordinates Weight


But it should be like as below (This is using another KPOINTS file)

B]
[
KPOINTS: k-points for bandstructure g-X-M-g-Z-R-A

Interpolating k-points between supplied coordinates.

Line segments in fractional coordinates (reciprocal lattice):
0.000000 0.000000 0.000000 ... 0.000000 0.500000 0.000000
0.000000 0.500000 0.000000 ... 0.500000 0.500000 0.000000
0.500000 0.500000 0.000000 ... 0.000000 0.000000 0.000000
0.000000 0.000000 0.000000 ... 0.000000 0.000000 0.500000
0.000000 0.000000 0.500000 ... 0.000000 0.500000 0.500000
0.000000 0.500000 0.500000 ... 0.500000 0.500000 0.500000
0.500000 0.500000 0.500000 ... 0.000000 0.000000 0.500000
0.000000 0.500000 0.000000 ... 0.000000 0.500000 0.500000
0.500000 0.500000 0.000000 ... 0.500000 0.500000 0.500000

Generated 100 points on each line segment, for a total of 900 k-points:
]
[
This is for KPOINTS file
k-points for bandstructure g-X-M-g-Z-R-A-Z X-R M-A
100
line
reciprocal
0.00000 0.00000 0.00000 0
0.00000 0.50000 0.00000 20

0.00000 0.50000 0.00000 0
0.50000 0.50000 0.00000 10

0.50000 0.50000 0.00000 0
0.00000 0.00000 0.00000 10

0.00000 0.00000 0.00000 0
0.00000 0.00000 0.50000 100

0.00000 0.00000 0.50000 0
0.00000 0.50000 0.50000 20

0.00000 0.50000 0.50000 0
0.50000 0.50000 0.50000 15

0.50000 0.50000 0.50000 0
0.00000 0.00000 0.50000 10

0.00000 0.50000 0.00000 0
0.00000 0.50000 0.50000 8

0.50000 0.50000 0.00000 0
0.50000 0.50000 0.50000 7
]

In both cases the program works fine and all k points are read succesfully (it is even writing that it detects 100 k points).

There is only a small issue with the comment strings:
The code reads the first line of the KPOINTS file which is treated as comment line.
This line is then output after " KPOINTS:" in the OUTCAR file.
The first comment line in the KPOINTS file is limited to 40 characters. If your line exceeds that than it is just cut after the 40th character.
This is exactly happening in your calculations.
You can either ignore the string or make it fit into 40 characters.

Thank you for your response.

Please provide me some information on K-points file
1)
KPOINTS: k-points for bandstructure g-M-x-g-Z-A #This is the comment line
100 # no of k-point sampling in each segment of the line created between high sym points
line
reciprocal
0.00000 0.00000 0.00000 0 g # co-ordinates (reciprocal space) weight of the segment g to Z in overall line like
0.00000 0.50000 0.00000 20 Z #20% from complete line while 80% from K to M

0.00000 0.50000 0.00000 0 K
0.50000 0.50000 0.00000 80 M

Are the comments written after # correct?
Does mentioning g,Z, K,M has any meaning or it's just comments to mention what these co-ordinates belong to?
2)
KPOINTS: k-points for bandstructure g-M-x-g-Z-A
100
line
reciprocal
0.00000 0.00000 0.00000 1 g # How does writting after co-ordinates 1 differs from the above first section?
0.00000 0.50000 0.00000 1 Z

0.00000 0.50000 0.00000 1 K
0.50000 0.50000 0.00000 1 M

How does these two KPOINTS file differ?

The KPOINTS files that you show have some issues:

In line mode no weights are read from the KPOINTS file (I've double checked with the code).
In that mode the k points are read as:
3 real numbers, 1 string. All separated by whitespace.
So the 4th entry for every k point is the label and everything that comes after that and is separated by white space is ignored.
So in your case 0, 1, 20, 80 etc. would be the label and g, Z, M etc. would be ignored.

Please have a careful look at the description on the KPOINTS file in our wiki:
https://www.vasp.at/wiki/index.php/KPOINTS