Dear TDEP developers,
I work with the last TDEP release (25.03).
I followed advices on the compilation of the code from the official webpage.
Then I started running the calculations for the BPO_4, material, which is identified by the TDEP as 'BCT2', which, I believe, correct.
However, if i run
extract_forceconstants -rc2 10.0
For any value of rc2, code just freezes. The reasoning behind it is, I believe, this block of code:
case('BCT')
! BCT a=b=c, al=be
call get_al_eq_be_order(latticevectors,m0)
call lo_get_axis_angles(m0,ap,bp,cp,ra,rb,rg)
a = sqrt(2.0_flyt)*ap*Sqrt(-Cos(ra) - Cos(rg))
b = sqrt(2.0_flyt)*bp*Sqrt(-Cos(ra) - Cos(rg))
c = 2*cp*Sqrt(-Cos(rb))
pri(:,1)=[-a/2,a/2,c/2]
pri(:,2)=[a/2,-a/2,c/2]
pri(:,3)=[a/2,a/2,-c/2]
con(:,1)=[a,0.0_flyt,0.0_flyt]
con(:,2)=[0.0_flyt,a,0.0_flyt]
con(:,3)=[0.0_flyt,0.0_flyt,c]
And, to be more precise, lines with sqrt of cosines. The assumes that cos values will be positive, which is not true. As a result, I obtain Nan for the values of lattice.
I changed the lattice value determination with this code:
case('BCT', 'BCT1', 'BCT2')
call get_al_eq_be_order(latticevectors,m0)
ap = norm2(m0(:,1))
d12 = dot_product(m0(:,1), m0(:,2))
d13 = dot_product(m0(:,1),m0(:,3))
d23 = dot_product(m0(:,2),m0(:,3))
dmin = min(d12, d13, d23)
a = sqrt(max(0.0_flyt, ap**2 - dmin))
b = a
c = sqrt(max(0.0_flyt, 2.0_flyt*(ap**2 + dmin)))
pri(:,1) = [-a/2, a/2, c/2]
pri(:,2) = [ a/2, -a/2, c/2]
pri(:,3) = [ a/2, a/2, -c/2]
con(:,1) = [a, 0.0_flyt, 0.0_flyt]
con(:,2) = [0.0_flyt, a, 0.0_flyt]
con(:,3) = [0.0_flyt, 0.0_flyt, c]
But high-symmetry path labeling doesn't work in this case correctly, which is make sense.
I've just manually turned off the error in this subroutine, and calculation passed.
Finally, after it I run
extract_forceconstants -rc2 10.0 --polar
But I obtain negative phonon frequencies. I did the calculations for 150 structures, which i suppose should be enough. Before it I also had calculations with 250 different structures, and result still was the same. So I don't think this is the problem related to the number of the structures.
Calculation without '--polar' options works perfectly fine
I provide all supplementary files, lmk if you'll need something else. I'll be glad to obtain any recommendations and feedback from you
Best,
Sergei
bpo.zip
Dear TDEP developers,
I work with the last TDEP release (25.03).
I followed advices on the compilation of the code from the official webpage.
Then I started running the calculations for the BPO_4, material, which is identified by the TDEP as 'BCT2', which, I believe, correct.
However, if i run
extract_forceconstants -rc2 10.0
For any value of rc2, code just freezes. The reasoning behind it is, I believe, this block of code:
And, to be more precise, lines with sqrt of cosines. The assumes that cos values will be positive, which is not true. As a result, I obtain Nan for the values of lattice.
I changed the lattice value determination with this code:
But high-symmetry path labeling doesn't work in this case correctly, which is make sense.
I've just manually turned off the error in this subroutine, and calculation passed.
Finally, after it I run
extract_forceconstants -rc2 10.0 --polar
But I obtain negative phonon frequencies. I did the calculations for 150 structures, which i suppose should be enough. Before it I also had calculations with 250 different structures, and result still was the same. So I don't think this is the problem related to the number of the structures.
Calculation without '--polar' options works perfectly fine
I provide all supplementary files, lmk if you'll need something else. I'll be glad to obtain any recommendations and feedback from you
Best,
Sergei
bpo.zip