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Dear Administrator,

i`m not understanding the format of the LOCPOT in the case of spin polarized calculations. In the manual i found that the data arrangment of LOCPOT is the same of the CHGCAR file.
What does it mean?
I would expect simply:
local_potential_up+local_potential_down (first block)
local_potential_up- local_potential_down (second block)
I`m not including the exchange correlation potential in the LOCPOT because the line INFO%LEXCHG=-1 in main.F is commented, but this should not be important about the format of LOCPOT.
In order to understand i just did something very simple:
-I run a calculation for a Cu111 slab along the z (vacuum on the top..i added dipole correction) with no spin polarized calculations and in LOCPOT i get just one block i expect to be local_potential_up+local_potential_down (A).
For this i can get the Workfunction and i get something that is reasonable.
-Then I run a calculation for a Cu111 slab along the z (vacuum on the top...i added dipole coorection) direction using spin polarized calculation. The LOCPOT file has two blocks (I and II) and instead of having the second block (II) full of zero, as i expected because no spin polarization has to be present at Cu ions (in the CHGCAR file the second block is full of 0.0 of 10E-04...), i have the second block (II) ugual to the first one (I), that is also almost ugual to one i got in case (A).
This doesn`t look as the format of CHGCAR.
Can you help me to understand?
Thank you a lot.

Gianluca

I stumbled upon this issue recently.
While the file format of LOCPOT is indeed similar to CHGCAR it does not contain the same data.
For spin unpolarized calculations it contains a single dataset with the potential.
For collinear spin calculations (ISPIN=2), it contains two datasets: spin up and spin down.
For noncollinear calculations (LNONCOLLINEAR=.TRUE.), it contains four datasets with spinor representation of the potential.

I updated the relevant wiki page:
https://www.vasp.at/wiki/wiki/index.php/LOCPOT