[Wannier] Initial choice for projection

[Young-Su Lee]

Dear Seunghwan,

I ran espresso/wannier90 with your input file to check whether there is a
bug in dis_proj_froz routine.
But, I couldn't reproduce the error you mentioned. Wannier90 finishes
without an error. 
Just one thing is that your frozen window is a bit high and seems to include
some states that should not be frozen.
Reducing it to 1.5 gives a good result. You can compare how they are
different - convergence, WF spread, imaginary part of H matrix.
Not sure what went wrong in  your calculation...

Young-Su





-----Original Message-----
From: seunghwan lee [mailto:seung43210 at yahoo.com] 
Sent: Tuesday, November 03, 2009 6:02 AM
To: Young-Su Lee
Cc: Wannier at quantum-espresso.org
Subject: RE: [Wannier] Initial choice for projection

Dear Young-Su and Nick,

I looked at the initial orbitals I set in the .win file and they are
actually consistent with what you suggested. I tried 2 unit cell as well and
got the same error message. (I attached .win file and scf input file for 2
unit cell)

   In dis_proj_froz... done
     1    95    95  1.001183578513  0.000000000000
 The trial orbitals for disentanglement are not orthonormal  Exiting.......
 Error in dis_main: orthonormal error 1

It looks like the problem is in NORMALIZATION of orbital #95 (s-orbital, if
W90 keep the ordering of initial orbitals), not orthogonality.
But it is difficult to understand that same orbitals defined in W90 are
normalized at one location and not normalized at another location.

There is a couple of even more strange behavior.

[1] If I change the number of significant figures for the location of
initial orbital, the nomalization changes. For example, if I use

c= 3.3780, -0.7128, -0.6157 :pz :z = 3.3780, -0.7128, 0.0000 :x=0,0,1

the error message was

--------------------------------------------------------------
 1    95    95  1.006000381851  0.000000000000
 The trial orbitals for disentanglement are not orthonormal  Exiting.......
-------------------------------------------------------------

But, if I use

c= 3.378034, -0.712837, -0.615700 :pz :z = 3.378034, -0.712837, 0.000000
:x=0,0,1

the error message was

--------------------------------------------------------------
     1    95    95  1.001183578513  0.000000000000
 The trial orbitals for disentanglement are not orthonormal  Exiting.......
-------------------------------------------------------------

Why normalization is anything to do with the location of orbitals?

[2] If I change the order of initial orbitals in the input file, I am still
getting the error for orbital #95. So, it is not really a problem of orbital
#95 in the previous input file.

It is possible that I made some stupid error in the input file (see my
attached input), but it looks like there is something strange going on with
normalization for a large carbon nanotube. But, PRL paper (Lee, Nardelli and
Marzari) used even larger nanotube and, so it has to work. Any idea what
might cause this kind of behavior? I am wondering if you used different
initial projections for 5 unit cell calculations reported in PRL paper.

Thank you. I really appreciate your help.

Seunghwan Lee

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