def __init__(self, symbol, configuration = None, xc = LDA,
maxiter = 200, mixing = 0.4, tol = 1e-6, output = None,
write = None):
"""
DFT atomic calculation.
Parameters:
symbol chemical symbol
configuration '[He] 2s2 2p2', overrides default from table
xc XC functional (LDA default)
"""
# store parameters
self.element = Element(symbol)
if configuration == None:
self.configuration = self.element.get_configuration()
else:
self.configuration = configuration
self.xc = xc
self.maxiter = maxiter
self.mixing = mixing
self.tol = tol
self.write = write
self.set_output(output)
# initialize grid, orbitals, energies
self.grid = RadialGrid(self.element.get_atomic_number())
self.setup_orbitals()
# print header
self.print_header()
class DFTAtom:
def __init__(self, symbol, configuration = None, xc = LDA,
maxiter = 200, mixing = 0.4, tol = 1e-6, output = None,
write = None):
"""
DFT atomic calculation.
Parameters:
symbol chemical symbol
configuration '[He] 2s2 2p2', overrides default from table
xc XC functional (LDA default)
"""
# store parameters
self.element = Element(symbol)
if configuration == None:
self.configuration = self.element.get_configuration()
else:
self.configuration = configuration
self.xc = xc
self.maxiter = maxiter
self.mixing = mixing
self.tol = tol
self.write = write
self.set_output(output)
# initialize grid, orbitals, energies
self.grid = RadialGrid(self.element.get_atomic_number())
self.setup_orbitals()
# print header
self.print_header()
def setup_orbitals(self):
"""Initialize atomic orbitals"""
self.config_tuple = parse_configuration(self.configuration)
self.orbitals = []
self.nelec = 0.0
for orb in self.config_tuple:
self.orbitals.append(Orbital(orb[0], orb[1], orb[2], self.grid.npoints))
self.nelec += orb[2]
def set_output(self, output):
"""Open output file"""
if output == None:
self.out = open(os.devnull, 'w')
elif output == '-':
self.out = sys.stdout
else:
self.out = open(output, 'a')
def print_header(self):
"""Print header information"""
print >> self.out, '='*78
print >> self.out, "DFT atomic calculation: Z = %i, name = %s" % (self.element.get_atomic_number(), self.element.get_name())
print >> self.out, '='*78
print >> self.out, "Radial grid : rmin = %f, rmax = %f, npoints = %i" % (self.grid.rmin, self.grid.rmax, self.grid.npoints)
print >> self.out, "Atomic configuration :", tuple_to_configuration(self.config_tuple)
print >> self.out, "Number of electrons :", self.nelec
print >> self.out, "Exchange-correlation :", self.xc.full_name
print >> self.out, "SCF : maxiter = %i, mixing = %f, tol = %f" % (self.maxiter, self.mixing, self.tol)
print >> self.out, ""
def print_eigenvalues(self):
"""Print eigenvalues and occupations"""
print >> self.out, "Eigenvalues:"
print >> self.out, " n l occ energy (Ha) energy (eV)"
for orb in self.orbitals:
print >> self.out, " %i %s %-6g %12.6f %12.6f" % (orb.n, orb.l, orb.occ, orb.ene, orb.ene*27.211383)
print >> self.out, ""
def print_energies(self):
"""Print final energies"""
print >> self.out, "Total energy : %12.4f Ha" % (self.e_tot)
print >> self.out, "Kinetic energy : %12.4f Ha" % (self.e_kin)
print >> self.out, "Ionic energy : %12.4f Ha" % (self.e_ion)
print >> self.out, "Hartree energy : %12.4f Ha" % (self.e_h)
print >> self.out, "XC energy : %12.4f Ha" % (self.e_xc)
def run_scf(self):
"""Run the SCF calculation"""
# initialize potential (pure coulomb)
npoints = self.grid.npoints
self.v_ion = -self.grid.zeta/self.grid.r
self.v_pot = self.v_ion.copy()
# start SCF iteration
rho_old = numpy.zeros(npoints)
e_old = 0.0
for it in xrange(1, self.maxiter):
# solve hydrogenoic problem for every orbital
for orb in self.orbitals:
ene, psi = solve_atom(self.grid, orb.n, orb.l, vpot = self.v_pot, maxiter = 50, tol = self.tol)
if ene != None:
orb.ene = ene
orb.psi = psi.copy()
# rho mixing
self.calculate_rho()
if it > 1:
self.rho = self.mixing*self.rho + (1.0 - self.mixing)*self.rho_old
self.rho_old = self.rho.copy()
# calculate potential
self.calculate_v_of_rho()
self.v_pot = self.v_ion + self.v_h + self.v_xc
# calculate energy
self.e_band = 0.0
for orb in self.orbitals:
self.e_band += orb.occ * orb.ene
self.e_tot = self.e_band - self.e_h + self.e_xc - self.e_vxc
self.e_kin = self.e_tot - self.e_ion - self.e_h - self.e_xc
de_tot = self.e_tot - e_old
e_old = self.e_tot
if it == 1:
print >> self.out, "Iteration Total energy Delta Energy"
print >> self.out, "%6i %12.6f %12.4e" % (it, self.e_tot, de_tot)
# check convergence and exit
if abs(de_tot) < self.tol:
break
# end of SCF, print energy and eigenvalues
print >> self.out, ""
self.print_energies()
self.print_eigenvalues()
def calculate_rho(self):
"""Calculate the charge density"""
self.rho = numpy.zeros(self.grid.npoints)
for orb in self.orbitals:
self.rho += orb.occ * (orb.psi*orb.psi) / self.grid.r2
nelec = self.grid.integrate_two(self.rho, self.grid.r2)
if abs(nelec - self.nelec) > 1e-4:
print >> self.out, "integrated charge (%f) different from number of electrons (%f)" % (nelec, self.nelec)
self.rho /= (4.0*math.pi)
def calculate_hartree(self, rho):
"""Calculate the Hartree potential from a given density"""
npoints = self.grid.npoints
r, r2, dr, dx = self.grid.r, self.grid.r2, self.grid.dr, self.grid.dx
# running charge
q = numpy.zeros(npoints)
for i in xrange(1,npoints):
q[i] = q[i-1] + 4.0*math.pi*r2[i] * dx*dr[i] * rho[i]
# hartree
v_h = numpy.zeros(npoints)
v_h[-1] = q[-1]/r[-1]
for i in xrange(npoints-1,0,-1):
v_h[i-1] = v_h[i] + dx * q[i]*self.grid.dr[i]/self.grid.r2[i]
e_h = 0.5*self.grid.integrate_two(v_h, rho * r2) * 4.0*math.pi
return e_h, v_h
def calculate_xc(self, rho):
"""Calculate the XC potential from a given density"""
npoints = self.grid.npoints
r, r2, dr, dx = self.grid.r, self.grid.r2, self.grid.dr, self.grid.dx
e_x = numpy.zeros(npoints)
v_x = numpy.zeros(npoints)
e_c = numpy.zeros(npoints)
v_c = numpy.zeros(npoints)
for i in xrange(len(rho)):
(e_x[i], v_x[i]), (e_c[i], v_c[i]) = self.xc.xc(rho[i])
v_xc = v_x + v_c
e_xc = self.grid.integrate_two(e_x + e_c, rho * r2) * 4.0*math.pi
e_vxc = self.grid.integrate_two(v_xc, rho * r2) * 4.0*math.pi
return e_xc, v_xc, e_vxc
def calculate_v_of_rho(self):
"""Calculate Hartree and XC, potential and energy"""
self.e_h, self.v_h = self.calculate_hartree(self.rho)
self.e_ion = self.grid.integrate_two(self.v_ion, self.rho*self.grid.r2) * 4.0*math.pi
self.e_xc, self.v_xc, self.e_vxc = self.calculate_xc(self.rho)
def __getstate__(self):
"""In order to implement pickle"""
odict = self.__dict__.copy()
del odict['out']
return odict
