def test_ke_cutoff(pseudo=None):
# The periodic calculation
eke_cut = []
eno_cut = []
max_ke = []
Ls = [5, 10, 15, 20, 25, 30, 40, 50]
for L in Ls:
cell = pbcgto.Cell()
cell.unit = 'B'
cell.h = np.diag([L,L,L])
cell.gs = np.array([20,20,20])
cell.nimgs = [0,0,0]
cell.atom = [['He', (L/2.,L/2.,L/2.)]]
cell.basis = { 'He': [[0, (0.8, 1.0)],
[0, (1.0, 1.0)],
[0, (1.2, 1.0)]] }
cell.pseudo = pseudo
cell.ke_cutoff = 10
cell.build()
mf = pbcrks.RKS(cell)
max_ke.append(np.max(0.5*np.einsum('gi,gi->g', cell.Gv, cell.Gv)))
eke_cut.append(mf.scf())
cell.ke_cutoff = None
cell.build()
mf = pbcrks.RKS(cell)
eno_cut.append(mf.scf())
# The basic idea is that for a fixed Ke cutoff, the
# basis functions do not change too much even when
# the box volume is being changed. So, one should
# find that the energy dependence with box size is smaller
# when a KE cutoff is employed.
for i, L in enumerate(Ls):
print "Ke Cutoff, L: %d, %f, %f" % (L, eke_cut[i], max_ke[i])
# Ke Cutoff, L: 5, -2.468773, 947.482023
# Ke Cutoff, L: 10, -2.466350, 236.870506
# Ke Cutoff, L: 15, -2.465358, 105.275780
# Ke Cutoff, L: 20, -2.462961, 59.217626
# Ke Cutoff, L: 25, -2.421159, 37.899281
# Ke Cutoff, L: 30, -2.263560, 26.318945
# Ke Cutoff, L: 40, -2.278470, 14.804407
# Ke Cutoff, L: 50, -3.386092, 9.474820
for i, L in enumerate(Ls):
print "No Cutoff, L: %d, %f, %f" % (L, eno_cut[i], max_ke[i])
def test_kscf_gamma(atom, ncells):
import numpy as np
# import warnings
cell = pbcgto.Cell()
cell.unit = 'B'
# As this is increased, we can see convergence between the molecule
# and cell calculation
Lunit = 2
Ly = Lz = 2
Lx = ncells * Lunit
cell.a = np.diag([Lx, Ly, Lz])
# place atom in middle of big box
for i in range(ncells):
cell.atom.extend([[atom, ((.5 + i) * Lunit, 0.5 * Ly, 0.5 * Lz)]])
cell.basis = {atom: [[0, (1.0, 1.0)]]}
n = 40
cell.gs = np.array([n * ncells, n, n])
cell.nimgs = [2, 2, 2]
cell.verbose = 7
cell.build()
#warnings.simplefilter("error", np.ComplexWarning)
kmf = pbcrks.RKS(cell)
kmf.init_guess = "atom"
return kmf.scf()
def test_ks(pseudo=None):
# The molecular calculation
mol = gto.Mole()
mol.unit = 'B'
L = 10
mol.atom.extend([
['He', (L / 2., L / 2., L / 2.)],
])
# these are some exponents which are not hard to integrate
mol.basis = {'He': [[0, (0.8, 1.0)], [0, (1.0, 1.0)], [0, (1.2, 1.0)]]}
mol.build()
m = rks.RKS(mol)
m.xc = 'LDA,VWN_RPA'
#m.xc = 'B88,LYP'
print "Molecular DFT energy"
print(m.scf())
# LDA,VWN_RPA
# -2.64096172441
# BLYP
# -2.66058401340308
# The periodic calculation
cell = pbcgto.Cell()
cell.unit = 'B'
cell.h = np.diag([L, L, L])
cell.gs = np.array([80, 80, 80])
cell.nimgs = [1, 1, 1]
cell.atom = mol.atom
cell.basis = mol.basis
cell.pseudo = pseudo
cell.build()
mf = pbcrks.RKS(cell)
mf.xc = 'LDA,VWN_RPA'
# mf.xc = 'B88,LYP'
print(mf.scf())
def KS(cell, *args, **kwargs):
if cell.spin == 0:
return rks.RKS(cell, *args, **kwargs)
else:
return uks.UKS(cell, *args, **kwargs)
def RKS(cell, *args, **kwargs):
if cell.spin == 0:
return rks.RKS(cell, *args, **kwargs)
else:
return roks.ROKS(cell, *args, **kwargs)