[Wien] wrap

[Rubel, Oleg]

You refer to an older version of BerryPI, which I do not have in place. I am inclined to think that the total phase is _not_ wrapped, but it would help to see your output tables (as below) before giving the exact answer. (please post to the list)

As of WIEN2k v21, ionic and electronic phases are not added up, instead the corresponding polarizations are after converting into Cartesian coordinate. It is needed for generic (non-orthogonal) lattice vectors. This is how the new output (BaTiO3 tutorial) looks like:
....
CALCULATION OF ELECTRONIC POLARIZATION (primitive lattice coordinates)
=======================================================================================
Value                           |  spin   |    dir(1)    |    dir(2)    |    dir(3)
---------------------------------------------------------------------------------------
Berry phase wrapped (rad)          sp(1)  [-2.660094e-13,  3.450573e-13,  1.258913e+00]
Berry phase (rad)                  up+dn  [-5.320189e-13,  6.901146e-13,  2.517826e+00]
Berry phase wrapped (rad)          up+dn  [-5.320189e-13,  6.901146e-13,  2.517826e+00]
Electronic polarization (C/m2)     sp(1)  [-8.415856e-14,  1.091673e-13,  4.024760e-01]
=======================================================================================

The electronic polarization vector is presented in this coord. system:
     dir(1) = [ 7.547566e+00,  4.621551e-16,  4.621551e-16] bohr
     dir(2) = [ 0.000000e+00,  7.547566e+00,  4.621551e-16] bohr
     dir(3) = [ 0.000000e+00,  0.000000e+00,  7.626934e+00] bohr
and will be transformed into Cartesian coordinates.


CALCULATION OF IONIC POLARIZATION (conventional lattice coordinates)
=======================================================================================
Elem.|  Fractional coord.  |  spin | Zion |    dir(1)    |    dir(2)    |    dir(3)
---------------------------------------------------------------------------------------
                                          +------------ Ionic phase (rad) ------------+
Ba  (0.0000, 0.0000, 0.0000)  sp(1) 10.00 [ 0.000000e+00,  0.000000e+00,  0.000000e+00]
Ti  (0.5000, 0.5000, 0.5152)  sp(1) 12.00 [ 3.769911e+01,  3.769911e+01,  3.884323e+01]
 O  (0.5000, 0.5000, 0.9736)  sp(1)  6.00 [ 1.884956e+01,  1.884956e+01,  3.670240e+01]
 O  (0.5000, 0.0000, 0.4834)  sp(1)  6.00 [ 1.884956e+01,  0.000000e+00,  1.822516e+01]
 O  (0.0000, 0.5000, 0.4834)  sp(1)  6.00 [ 0.000000e+00,  1.884956e+01,  1.822516e+01]
---------------------------------------------------------------------------------------
Total ionic phase (rad)       sp(1)       [ 7.539822e+01,  7.539822e+01,  1.119960e+02]
Total ionic phase wrap. (rad) sp(1)       [ 3.552714e-15,  3.552714e-15, -1.101384e+00]
Ionic polarization (C/m2)     sp(1)       [ 5.619937e-16,  5.619937e-16, -1.760570e-01]
=======================================================================================
The ionic positions and associated polarization vector is presented in this coord. system:
     dir(1) = [ 7.547566e+00,  4.621551e-16,  4.621551e-16] bohr
     dir(2) = [ 0.000000e+00,  7.547566e+00,  4.621551e-16] bohr
     dir(3) = [ 0.000000e+00,  0.000000e+00,  7.626934e+00] bohr


SUMMARY OF POLARIZATION CALCULATION IN CARTESIAN COORDINATES
=======================================================================================
Value                           |  spin   |       X      |       Y      |       Z
---------------------------------------------------------------------------------------
Electronic polarization (C/m2)     sp(1)  [-8.415856e-14,  1.091673e-13,  4.024760e-01]
Ionic polarization (C/m2)          sp(1)  [ 5.619937e-16,  5.619937e-16, -1.760570e-01]
Tot. spin polariz.=Pion+Pel (C/m2) sp(1)  [-8.359656e-14,  1.097293e-13,  2.264190e-01]
---------------------------------------------------------------------------------------
TOTAL POLARIZATION (C/m2)          both   [-8.359656e-14,  1.097293e-13,  2.264190e-01]
=======================================================================================

As one can see, there is no "Total phase" only "Tot. spin polariz.=Pion+Pel".

I hope it will help
Oleg

________________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of shahrbano rahimi <shahrbanorahimi60 at gmail.com>
Sent: Friday, May 28, 2021 12:31
To: wien at zeus.theochem.tuwien.ac.at
Subject: [Wien] wrap

Dear Prof. Rubel Oleg and WIEN2k users,
I have a general question concerning Berry phase calculations.
Would you, please, let me know that in the BerryPI package whether only the ionic and electronic parts of the phase are wrapped into the [-pi, pi] or the total phase is also wrapped into this interval. By this I mean that if the total phase after summing the wrapped ionic and electronic parts became larger than pi or smaller than -pi, whether the BerryPI package also wraps the total phase into the interval [-pi, pi] or leaves it to be located outside of the interval?
The BerryPI version: 1.4.0 (May 25, 2018)
The Wien2k version:18.2
Sincerely,