[gpaw-users] TPSS band structure
Lara Ferrighi
laraf at phys.au.dk
Wed Feb 15 16:24:32 CET 2012
Hei again,
I should also mention, as a member of our group pointed out, that M06-L
(which is
also a MGGA) was giving poor/wrong band structure when tried with fixed
density. A
way to get around it and have a good performance is to use a tight k-point
sampling
in one direction.
Good luck,
Lara
> Hei Markus,
> I've never done the band structure myself, but before running a MGGA
> calculation
> you need to run something else to create the wave function (for the
> kinetic energy
> density needed in MGGAs). My guess would be that you need to run a PBE
> before TPSS
> when you scan for Kpoints for the band structure.
>
> Best, Lara
>
>> Dear GPAW users and developers,
>>
>> I am trying to compute the band structure of bcc Fe with TPSS. I can
>> easily compute it with PBE, and I can obtain the ground state and DOS
>> with TPSS. However, there seems to be a problem with the band structure,
>> which I try to compute according to the Si tutorial. Is this the right
>> way to do it? I am using gpaw 0.9.0.8711. Here's the full script, that
>> computes the PBE ground state, restarts with TPSS, computes the PBE band
>> structure and fails for the TPSS band structure:
>>
>> ################
>> ################
>>
>> import pickle
>> import numpy as np
>> from ase import *
>> from ase.dft.kpoints import ibz_points, get_bandpath
>> from ase.parallel import parprint
>> from gpaw import GPAW, FermiDirac, restart
>>
>> def groundstate(a, k, xctype):
>> atoms = Atoms(
>> 'Fe',
>> [(0,0,0)],
>> cell=[(-0.5*a, 0.5*a, 0.5*a),(0.5*a, -0.5*a,
>> 0.5*a),(0.5*a, 0.5*a, -0.5*a)],
>> pbc=True,
>> magmoms=[2.2]
>> )
>>
>> atoms.calc = GPAW(
>> kpts=(k, k, k),
>> xc=xctype,
>> spinpol=True,
>> gpts=(16, 16, 16),
>> stencils=(5,3),
>> usesymm=True,
>> nbands=16,
>> occupations=FermiDirac(0.05),
>> parallel={'domain': 1},
>> convergence={'eigenstates': 1e-7},
>> txt='Fe-PBE.txt'
>> )
>> atoms.get_potential_energy()
>> return atoms
>>
>> a = 2.861
>> k = 20
>>
>> # run the PBE calculation
>> parprint('PBE ground state run')
>> system = groundstate(a, k, 'PBE')
>> system.calc.write('PBE.gpw', mode='all')
>>
>> # run the TPSS calculation
>> parprint('TPSS ground state run')
>> system, calc = restart('PBE.gpw', txt='Fe-TPSS.txt',
>> convergence={'eigenstates': 1e-7})
>> calc.set(xc='TPSS')
>> calc.get_potential_energy()
>> system.calc.write('TPSS.gpw', mode='all')
>>
>> # calculate the band structure for PBE
>> parprint('band structure run for PBE')
>> points = ibz_points['bcc']
>> G = points['Gamma']
>> P = points['P']
>> H = points['H']
>>
>> calc = GPAW('PBE.gpw',
>> txt='PBE-bandstructure.txt',
>> spinpol=True,
>> parallel={'domain': 1},
>> fixdensity=True,
>> usesymm=None,
>> convergence={'bands': 12},
>> eigensolver='cg',
>> occupations=FermiDirac(0.05)
>> )
>>
>> kpts, x, X = get_bandpath([G, H, P, G], calc.atoms.cell, npoints=100)
>> calc.set(kpts=kpts)
>> calc.get_potential_energy()
>>
>> ef = calc.get_fermi_level()
>>
>> e_kn_0 = np.array([calc.get_eigenvalues(k, spin=0)-ef for k in
>> range(len(kpts))])
>> e_kn_1 = np.array([calc.get_eigenvalues(k, spin=1)-ef for k in
>> range(len(kpts))])
>> pickle.dump((x, X, e_kn_0, e_kn_1), open('PBE.pckl', 'w'))
>>
>> # calculate the band structure for TPSS
>> parprint('band structure run for TPSS')
>> calc = GPAW('TPSS.gpw',
>> txt='TPSS-bandstructure.txt',
>> spinpol=True,
>> parallel={'domain': 1},
>> fixdensity=True,
>> usesymm=None,
>> convergence={'bands': 12},
>> eigensolver='cg',
>> occupations=FermiDirac(0.05)
>> )
>>
>> kpts, x, X = get_bandpath([G, H, P, G], calc.atoms.cell, npoints=100)
>> calc.set(kpts=kpts)
>> calc.get_potential_energy()
>>
>> ef = calc.get_fermi_level()
>>
>> e_kn_0 = np.array([calc.get_eigenvalues(k, spin=0)-ef for k in
>> range(len(kpts))])
>> e_kn_1 = np.array([calc.get_eigenvalues(k, spin=1)-ef for k in
>> range(len(kpts))])
>> pickle.dump((x, X, e_kn_0, e_kn_1), open('TPSS.pckl', 'w'))
>>
>> #######################
>> #######################
>>
>> Traceback (most recent call last):
>> File "b.py", line 28, in <module>
>> calc.get_potential_energy()
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/aseinterface.py", line
>> 37, in get_potential_energy
>> self.calculate(atoms, converge=True)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/paw.py", line 245, in
>> calculate
>> self.set_positions(atoms)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/paw.py", line 303, in
>> set_positions
>> self.wfs.initialize(self.density, self.hamiltonian, spos_ac)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/wavefunctions/fdpw.py",
>> line 70, in initialize
>> hamiltonian.update(density)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/hamiltonian.py", line
>> 202, in update
>> self.update_pseudo_potential(density)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/hamiltonian.py", line
>> 467, in update_pseudo_potential
>> Exc = self.xc.calculate(self.finegd, density.nt_sg, self.vt_sg)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/xc/lda.py", line 22, in
>> calculate
>> self.calculate_lda(e_g, n_sg, v_sg)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/xc/gga.py", line 28, in
>> calculate_lda
>> self.calculate_gga(e_g, n_sg, v_sg, sigma_xg, dedsigma_xg)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/xc/mgga.py", line 51,
>> in calculate_gga
>> taut_sG = self.wfs.calculate_kinetic_energy_density(self.taugrad_v)
>> File "/home/meinert/gpaw/gpaw-0.9.0.8711/gpaw/wavefunctions/fd.py",
>> line 95, in calculate_kinetic_energy_density
>> for f, psit_G in zip(kpt.f_n, kpt.psit_nG):
>> TypeError: zip argument #1 must support iteration
>> GPAW CLEANUP for serial binary: <type 'exceptions.TypeError'> occured.
>> Calling sys.exit()
>>
>> ############################
>> ############################
>>
>>
>> Thanks a lot in advance,
>> Markus
>>
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