def lanczos_minmax(F,S=None,**kwargs): "Estimate the min/max evals of F using a few iters of Lanczos" doS = S is not None niter = kwargs.get('niter',8) N = F.shape[0] niter = min(N,niter) x = zeros(N,'d') x[0] = 1 q = x avals = [] bvals = [] if doS: r = matrixmultiply(S,q) else: r = q beta = sqrt(matrixmultiply(q,r)) wold = zeros(N,'d') for i in xrange(niter): w = r/beta v = q/beta r = matrixmultiply(F,v) r = r - wold*beta alpha = matrixmultiply(v,r) avals.append(alpha) r = r-w*alpha if doS: q = solve(S,r) else: q = r beta = sqrt(matrixmultiply(q,r)) bvals.append(beta) wold = w E,V = eigh(tridiagmat(avals,bvals)) return min(E),max(E)
def lanczos_minmax(F, S=None, **kwargs): "Estimate the min/max evals of F using a few iters of Lanczos" doS = S is not None niter = kwargs.get('niter', settings.DMPLanczosMinmaxIters) N = F.shape[0] niter = min(N, niter) x = zeros(N, 'd') x[0] = 1 q = x avals = [] bvals = [] if doS: r = matrixmultiply(S, q) else: r = q beta = sqrt(matrixmultiply(q, r)) wold = zeros(N, 'd') for i in xrange(niter): w = r / beta v = q / beta r = matrixmultiply(F, v) r = r - wold * beta alpha = matrixmultiply(v, r) avals.append(alpha) r = r - w * alpha if doS: q = solve(S, r) else: q = r beta = sqrt(matrixmultiply(q, r)) bvals.append(beta) wold = w E, V = eigh(tridiagmat(avals, bvals)) return min(E), max(E)
def getF(self, F, D): n, m = F.shape err = matrixmultiply(F, matrixmultiply(D, self.S)) - matrixmultiply(self.S, matrixmultiply(D, F)) err = ravel(err) maxerr = max(abs(err)) self.maxerr = maxerr if maxerr < self.errcutoff and not self.started: if VERBOSE: print "Starting DIIS: Max Err = ", maxerr self.started = 1 if not self.started: # Do simple averaging until DIIS starts if self.Fold != None: Freturn = 0.5 * F + 0.5 * self.Fold self.Fold = F else: self.Fold = F Freturn = F return Freturn self.Fs.append(F) self.Errs.append(err) nit = len(self.Errs) a = zeros((nit + 1, nit + 1), "d") b = zeros(nit + 1, "d") for i in range(nit): for j in range(nit): a[i, j] = dot(self.Errs[i], self.Errs[j]) for i in range(nit): a[nit, i] = a[i, nit] = -1.0 b[i] = 0 # mtx2file(a,'A%d.dat' % nit) a[nit, nit] = 0 b[nit] = -1.0 # The try loop makes this a bit more stable. # Thanks to John Kendrick! try: c = solve(a, b) except: self.Fold = F return F F = zeros((n, m), "d") for i in range(nit): F += c[i] * self.Fs[i] return F
def getF(self, F, D): n, m = F.shape err = matrixmultiply(F,matrixmultiply(D,self.S)) -\ matrixmultiply(self.S,matrixmultiply(D,F)) err = ravel(err) maxerr = max(abs(err)) self.maxerr = maxerr if maxerr < self.errcutoff and not self.started: if VERBOSE: print "Starting DIIS: Max Err = ", maxerr self.started = 1 if not self.started: # Do simple averaging until DIIS starts if self.Fold != None: Freturn = 0.5 * F + 0.5 * self.Fold self.Fold = F else: self.Fold = F Freturn = F return Freturn self.Fs.append(F) self.Errs.append(err) nit = len(self.Errs) a = zeros((nit + 1, nit + 1), 'd') b = zeros(nit + 1, 'd') for i in xrange(nit): for j in xrange(nit): a[i, j] = dot(self.Errs[i], self.Errs[j]) for i in xrange(nit): a[nit, i] = a[i, nit] = -1.0 b[i] = 0 #mtx2file(a,'A%d.dat' % nit) a[nit, nit] = 0 b[nit] = -1.0 # The try loop makes this a bit more stable. # Thanks to John Kendrick! try: c = solve(a, b) except: self.Fold = F return F F = zeros((n, m), 'd') for i in xrange(nit): F += c[i] * self.Fs[i] return F
def getF(self, F, D): n, m = F.shape err = matrixmultiply(F, matrixmultiply(D, self.S)) - matrixmultiply(self.S, matrixmultiply(D, F)) err = ravel(err) maxerr = max(abs(err)) if maxerr < self.errcutoff and not self.started: if VERBOSE: print "Starting DIIS: Max Err = ", maxerr self.started = 1 if not self.started: # Do simple averaging until DIIS starts if self.Fold: Freturn = 0.5 * F + 0.5 * self.Fold else: Freturn = F self.Fold = F return Freturn elif not self.errold: Freturn = 0.5 * F + 0.5 * self.Fold self.errold = err return Freturn a = zeros((3, 3), "d") b = zeros(3, "d") a[0, 0] = dot(self.errold, self.errold) a[1, 0] = dot(self.errold, err) a[0, 1] = a[1, 0] a[1, 1] = dot(err, err) a[:, 2] = -1 a[2, :] = -1 a[2, 2] = 0 b[2] = -1 c = solve(a, b) # Handle a few special cases: alpha = c[1] print alpha, c # if alpha < 0: alpha = 0 # if alpha > 1: alpha = 1 F = (1 - alpha) * self.Fold + alpha * F self.errold = err self.Fold = F return F
def getF(self, F, D): n, m = F.shape err = matrixmultiply(F,matrixmultiply(D,self.S)) -\ matrixmultiply(self.S,matrixmultiply(D,F)) err = ravel(err) maxerr = max(abs(err)) if maxerr < self.errcutoff and not self.started: if VERBOSE: print "Starting DIIS: Max Err = ", maxerr self.started = 1 if not self.started: # Do simple averaging until DIIS starts if self.Fold: Freturn = 0.5 * F + 0.5 * self.Fold else: Freturn = F self.Fold = F return Freturn elif not self.errold: Freturn = 0.5 * F + 0.5 * self.Fold self.errold = err return Freturn a = zeros((3, 3), 'd') b = zeros(3, 'd') a[0, 0] = dot(self.errold, self.errold) a[1, 0] = dot(self.errold, err) a[0, 1] = a[1, 0] a[1, 1] = dot(err, err) a[:, 2] = -1 a[2, :] = -1 a[2, 2] = 0 b[2] = -1 c = solve(a, b) # Handle a few special cases: alpha = c[1] print alpha, c #if alpha < 0: alpha = 0 #if alpha > 1: alpha = 1 F = (1 - alpha) * self.Fold + alpha * F self.errold = err self.Fold = F return F
def oep_uhf_an(atoms,orbsa,orbsb,**opts): """oep_hf - Form the optimized effective potential for HF exchange. Implementation of Wu and Yang's Approximate Newton Scheme from J. Theor. Comp. Chem. 2, 627 (2003). oep_uhf(atoms,orbs,**opts) atoms A Molecule object containing a list of the atoms orbs A matrix of guess orbitals Options ------- bfs None The basis functions to use for the wfn pbfs None The basis functions to use for the pot basis_data None The basis data to use to construct bfs integrals None The one- and two-electron integrals to use If not None, S,h,Ints """ maxiter = opts.get('maxiter',100) tol = opts.get('tol',1e-5) ETemp = opts.get('ETemp',False) bfs = opts.get('bfs',None) if not bfs: basis = opts.get('basis',None) bfs = getbasis(atoms,basis) # The basis set for the potential can be set different from # that used for the wave function pbfs = opts.get('pbfs',None) if not pbfs: pbfs = bfs npbf = len(pbfs) integrals = opts.get('integrals',None) if integrals: S,h,Ints = integrals else: S,h,Ints = getints(bfs,atoms) nel = atoms.get_nel() nclosed,nopen = atoms.get_closedopen() nalpha,nbeta = nclosed+nopen,nclosed Enuke = atoms.get_enuke() # Form the OEP using Yang/Wu, PRL 89 143002 (2002) nbf = len(bfs) norb = nbf ba = zeros(npbf,'d') bb = zeros(npbf,'d') # Form and store all of the three-center integrals # we're going to need. # These are <ibf|gbf|jbf> (where 'bf' indicates basis func, # as opposed to MO) # N^3 storage -- obviously you don't want to do this for # very large systems Gij = [] for g in range(npbf): gmat = zeros((nbf,nbf),'d') Gij.append(gmat) gbf = pbfs[g] for i in range(nbf): ibf = bfs[i] for j in range(i+1): jbf = bfs[j] gij = three_center(ibf,gbf,jbf) gmat[i,j] = gij gmat[j,i] = gij # Compute the Fermi-Amaldi potential based on the LDA density. # We're going to form this matrix from the Coulombic matrix that # arises from the input orbitals. D0 and J0 refer to the density # matrix and corresponding Coulomb matrix D0 = mkdens(orbsa,0,nalpha)+mkdens(orbsb,0,nbeta) J0 = getJ(Ints,D0) Vfa = ((nel-1.)/nel)*J0 H0 = h + Vfa eold = 0 for iter in range(maxiter): Hoepa = get_Hoep(ba,H0,Gij) Hoepb = get_Hoep(ba,H0,Gij) orbea,orbsa = geigh(Hoepa,S) orbeb,orbsb = geigh(Hoepb,S) if ETemp: efermia = get_efermi(2*nalpha,orbea,ETemp) occsa = get_fermi_occs(efermia,orbea,ETemp) Da = mkdens_occs(orbsa,occsa) efermib = get_efermi(2*nbeta,orbeb,ETemp) occsb = get_fermi_occs(efermib,orbeb,ETemp) Db = mkdens_occs(orbsb,occsb) entropy = 0.5*(get_entropy(occsa,ETemp)+get_entropy(occsb,ETemp)) else: Da = mkdens(orbsa,0,nalpha) Db = mkdens(orbsb,0,nbeta) J = getJ(Ints,Da) + getJ(Ints,Db) Ka = getK(Ints,Da) Kb = getK(Ints,Db) energy = (trace2(2*h+J-Ka,Da)+trace2(2*h+J-Kb,Db))/2\ +Enuke if ETemp: energy += entropy if abs(energy-eold) < tol: break else: eold = energy logging.debug("OEP AN Opt: %d %f" % (iter,energy)) # Do alpha and beta separately # Alphas dV_ao = J-Ka-Vfa dV = matrixmultiply(orbsa,matrixmultiply(dV_ao,transpose(orbsa))) X = zeros((nbf,nbf),'d') c = zeros(nbf,'d') for k in range(nbf): Gk = matrixmultiply(orbsa,matrixmultiply(Gij[k], transpose(orbsa))) for i in range(nalpha): for a in range(nalpha,norb): c[k] += dV[i,a]*Gk[i,a]/(orbea[i]-orbea[a]) for l in range(nbf): Gl = matrixmultiply(orbsa,matrixmultiply(Gij[l], transpose(orbsa))) for i in range(nalpha): for a in range(nalpha,norb): X[k,l] += Gk[i,a]*Gl[i,a]/(orbea[i]-orbea[a]) # This should actually be a pseudoinverse... ba = solve(X,c) # Betas dV_ao = J-Kb-Vfa dV = matrixmultiply(orbsb,matrixmultiply(dV_ao,transpose(orbsb))) X = zeros((nbf,nbf),'d') c = zeros(nbf,'d') for k in range(nbf): Gk = matrixmultiply(orbsb,matrixmultiply(Gij[k], transpose(orbsb))) for i in range(nbeta): for a in range(nbeta,norb): c[k] += dV[i,a]*Gk[i,a]/(orbeb[i]-orbeb[a]) for l in range(nbf): Gl = matrixmultiply(orbsb,matrixmultiply(Gij[l], transpose(orbsb))) for i in range(nbeta): for a in range(nbeta,norb): X[k,l] += Gk[i,a]*Gl[i,a]/(orbeb[i]-orbeb[a]) # This should actually be a pseudoinverse... bb = solve(X,c) logging.info("Final OEP energy = %f" % energy) return energy,(orbea,orbeb),(orbsa,orbsb)
def oep_hf_an(atoms,orbs,**opts): """oep_hf - Form the optimized effective potential for HF exchange. Implementation of Wu and Yang's Approximate Newton Scheme from J. Theor. Comp. Chem. 2, 627 (2003). oep_hf(atoms,orbs,**opts) atoms A Molecule object containing a list of the atoms orbs A matrix of guess orbitals Options ------- bfs None The basis functions to use for the wfn pbfs None The basis functions to use for the pot basis_data None The basis data to use to construct bfs integrals None The one- and two-electron integrals to use If not None, S,h,Ints """ maxiter = opts.get('maxiter',100) tol = opts.get('tol',1e-5) bfs = opts.get('bfs',None) if not bfs: basis = opts.get('basis',None) bfs = getbasis(atoms,basis) # The basis set for the potential can be set different from # that used for the wave function pbfs = opts.get('pbfs',None) if not pbfs: pbfs = bfs npbf = len(pbfs) integrals = opts.get('integrals',None) if integrals: S,h,Ints = integrals else: S,h,Ints = getints(bfs,atoms) nel = atoms.get_nel() nocc,nopen = atoms.get_closedopen() Enuke = atoms.get_enuke() # Form the OEP using Yang/Wu, PRL 89 143002 (2002) nbf = len(bfs) norb = nbf bp = zeros(nbf,'d') bvec = opts.get('bvec',None) if bvec: assert len(bvec) == npbf b = array(bvec) else: b = zeros(npbf,'d') # Form and store all of the three-center integrals # we're going to need. # These are <ibf|gbf|jbf> (where 'bf' indicates basis func, # as opposed to MO) # N^3 storage -- obviously you don't want to do this for # very large systems Gij = [] for g in range(npbf): gmat = zeros((nbf,nbf),'d') Gij.append(gmat) gbf = pbfs[g] for i in range(nbf): ibf = bfs[i] for j in range(i+1): jbf = bfs[j] gij = three_center(ibf,gbf,jbf) gmat[i,j] = gij gmat[j,i] = gij # Compute the Fermi-Amaldi potential based on the LDA density. # We're going to form this matrix from the Coulombic matrix that # arises from the input orbitals. D0 and J0 refer to the density # matrix and corresponding Coulomb matrix D0 = mkdens(orbs,0,nocc) J0 = getJ(Ints,D0) Vfa = (2*(nel-1.)/nel)*J0 H0 = h + Vfa b = zeros(nbf,'d') eold = 0 for iter in range(maxiter): Hoep = get_Hoep(b,H0,Gij) orbe,orbs = geigh(Hoep,S) D = mkdens(orbs,0,nocc) Vhf = get2JmK(Ints,D) energy = trace2(2*h+Vhf,D)+Enuke if abs(energy-eold) < tol: break else: eold = energy logging.debug("OEP AN Opt: %d %f" % (iter,energy)) dV_ao = Vhf-Vfa dV = matrixmultiply(transpose(orbs),matrixmultiply(dV_ao,orbs)) X = zeros((nbf,nbf),'d') c = zeros(nbf,'d') Gkt = zeros((nbf,nbf),'d') for k in range(nbf): # This didn't work; in fact, it made things worse: Gk = matrixmultiply(transpose(orbs),matrixmultiply(Gij[k],orbs)) for i in range(nocc): for a in range(nocc,norb): c[k] += dV[i,a]*Gk[i,a]/(orbe[i]-orbe[a]) for l in range(nbf): Gl = matrixmultiply(transpose(orbs),matrixmultiply(Gij[l],orbs)) for i in range(nocc): for a in range(nocc,norb): X[k,l] += Gk[i,a]*Gl[i,a]/(orbe[i]-orbe[a]) # This should actually be a pseudoinverse... b = solve(X,c) logging.info("Final OEP energy = %f" % energy) return energy,orbe,orbs
def oep_uhf_an(atoms, orbsa, orbsb, **opts): """oep_hf - Form the optimized effective potential for HF exchange. Implementation of Wu and Yang's Approximate Newton Scheme from J. Theor. Comp. Chem. 2, 627 (2003). oep_uhf(atoms,orbs,**opts) atoms A Molecule object containing a list of the atoms orbs A matrix of guess orbitals Options ------- bfs None The basis functions to use for the wfn pbfs None The basis functions to use for the pot basis_data None The basis data to use to construct bfs integrals None The one- and two-electron integrals to use If not None, S,h,Ints """ maxiter = opts.get('maxiter', 100) tol = opts.get('tol', 1e-5) ETemp = opts.get('ETemp', False) bfs = opts.get('bfs', None) if not bfs: basis = opts.get('basis', None) bfs = getbasis(atoms, basis) # The basis set for the potential can be set different from # that used for the wave function pbfs = opts.get('pbfs', None) if not pbfs: pbfs = bfs npbf = len(pbfs) integrals = opts.get('integrals', None) if integrals: S, h, Ints = integrals else: S, h, Ints = getints(bfs, atoms) nel = atoms.get_nel() nclosed, nopen = atoms.get_closedopen() nalpha, nbeta = nclosed + nopen, nclosed Enuke = atoms.get_enuke() # Form the OEP using Yang/Wu, PRL 89 143002 (2002) nbf = len(bfs) norb = nbf ba = zeros(npbf, 'd') bb = zeros(npbf, 'd') # Form and store all of the three-center integrals # we're going to need. # These are <ibf|gbf|jbf> (where 'bf' indicates basis func, # as opposed to MO) # N^3 storage -- obviously you don't want to do this for # very large systems Gij = [] for g in xrange(npbf): gmat = zeros((nbf, nbf), 'd') Gij.append(gmat) gbf = pbfs[g] for i in xrange(nbf): ibf = bfs[i] for j in xrange(i + 1): jbf = bfs[j] gij = three_center(ibf, gbf, jbf) gmat[i, j] = gij gmat[j, i] = gij # Compute the Fermi-Amaldi potential based on the LDA density. # We're going to form this matrix from the Coulombic matrix that # arises from the input orbitals. D0 and J0 refer to the density # matrix and corresponding Coulomb matrix D0 = mkdens(orbsa, 0, nalpha) + mkdens(orbsb, 0, nbeta) J0 = getJ(Ints, D0) Vfa = ((nel - 1.) / nel) * J0 H0 = h + Vfa eold = 0 for iter in xrange(maxiter): Hoepa = get_Hoep(ba, H0, Gij) Hoepb = get_Hoep(ba, H0, Gij) orbea, orbsa = geigh(Hoepa, S) orbeb, orbsb = geigh(Hoepb, S) if ETemp: efermia = get_efermi(2 * nalpha, orbea, ETemp) occsa = get_fermi_occs(efermia, orbea, ETemp) Da = mkdens_occs(orbsa, occsa) efermib = get_efermi(2 * nbeta, orbeb, ETemp) occsb = get_fermi_occs(efermib, orbeb, ETemp) Db = mkdens_occs(orbsb, occsb) entropy = 0.5 * (get_entropy(occsa, ETemp) + get_entropy(occsb, ETemp)) else: Da = mkdens(orbsa, 0, nalpha) Db = mkdens(orbsb, 0, nbeta) J = getJ(Ints, Da) + getJ(Ints, Db) Ka = getK(Ints, Da) Kb = getK(Ints, Db) energy = (trace2(2*h+J-Ka,Da)+trace2(2*h+J-Kb,Db))/2\ +Enuke if ETemp: energy += entropy if abs(energy - eold) < tol: break else: eold = energy logging.debug("OEP AN Opt: %d %f" % (iter, energy)) # Do alpha and beta separately # Alphas dV_ao = J - Ka - Vfa dV = matrixmultiply(orbsa, matrixmultiply(dV_ao, transpose(orbsa))) X = zeros((nbf, nbf), 'd') c = zeros(nbf, 'd') for k in xrange(nbf): Gk = matrixmultiply(orbsa, matrixmultiply(Gij[k], transpose(orbsa))) for i in xrange(nalpha): for a in xrange(nalpha, norb): c[k] += dV[i, a] * Gk[i, a] / (orbea[i] - orbea[a]) for l in xrange(nbf): Gl = matrixmultiply(orbsa, matrixmultiply(Gij[l], transpose(orbsa))) for i in xrange(nalpha): for a in xrange(nalpha, norb): X[k, l] += Gk[i, a] * Gl[i, a] / (orbea[i] - orbea[a]) # This should actually be a pseudoinverse... ba = solve(X, c) # Betas dV_ao = J - Kb - Vfa dV = matrixmultiply(orbsb, matrixmultiply(dV_ao, transpose(orbsb))) X = zeros((nbf, nbf), 'd') c = zeros(nbf, 'd') for k in xrange(nbf): Gk = matrixmultiply(orbsb, matrixmultiply(Gij[k], transpose(orbsb))) for i in xrange(nbeta): for a in xrange(nbeta, norb): c[k] += dV[i, a] * Gk[i, a] / (orbeb[i] - orbeb[a]) for l in xrange(nbf): Gl = matrixmultiply(orbsb, matrixmultiply(Gij[l], transpose(orbsb))) for i in xrange(nbeta): for a in xrange(nbeta, norb): X[k, l] += Gk[i, a] * Gl[i, a] / (orbeb[i] - orbeb[a]) # This should actually be a pseudoinverse... bb = solve(X, c) logger.info("Final OEP energy = %f" % energy) return energy, (orbea, orbeb), (orbsa, orbsb)
def oep_hf_an(atoms, orbs, **opts): """oep_hf - Form the optimized effective potential for HF exchange. Implementation of Wu and Yang's Approximate Newton Scheme from J. Theor. Comp. Chem. 2, 627 (2003). oep_hf(atoms,orbs,**opts) atoms A Molecule object containing a list of the atoms orbs A matrix of guess orbitals Options ------- bfs None The basis functions to use for the wfn pbfs None The basis functions to use for the pot basis_data None The basis data to use to construct bfs integrals None The one- and two-electron integrals to use If not None, S,h,Ints """ maxiter = opts.get('maxiter', 100) tol = opts.get('tol', 1e-5) bfs = opts.get('bfs', None) if not bfs: basis = opts.get('basis', None) bfs = getbasis(atoms, basis) # The basis set for the potential can be set different from # that used for the wave function pbfs = opts.get('pbfs', None) if not pbfs: pbfs = bfs npbf = len(pbfs) integrals = opts.get('integrals', None) if integrals: S, h, Ints = integrals else: S, h, Ints = getints(bfs, atoms) nel = atoms.get_nel() nocc, nopen = atoms.get_closedopen() Enuke = atoms.get_enuke() # Form the OEP using Yang/Wu, PRL 89 143002 (2002) nbf = len(bfs) norb = nbf bp = zeros(nbf, 'd') bvec = opts.get('bvec', None) if bvec: assert len(bvec) == npbf b = array(bvec) else: b = zeros(npbf, 'd') # Form and store all of the three-center integrals # we're going to need. # These are <ibf|gbf|jbf> (where 'bf' indicates basis func, # as opposed to MO) # N^3 storage -- obviously you don't want to do this for # very large systems Gij = [] for g in xrange(npbf): gmat = zeros((nbf, nbf), 'd') Gij.append(gmat) gbf = pbfs[g] for i in xrange(nbf): ibf = bfs[i] for j in xrange(i + 1): jbf = bfs[j] gij = three_center(ibf, gbf, jbf) gmat[i, j] = gij gmat[j, i] = gij # Compute the Fermi-Amaldi potential based on the LDA density. # We're going to form this matrix from the Coulombic matrix that # arises from the input orbitals. D0 and J0 refer to the density # matrix and corresponding Coulomb matrix D0 = mkdens(orbs, 0, nocc) J0 = getJ(Ints, D0) Vfa = (2 * (nel - 1.) / nel) * J0 H0 = h + Vfa b = zeros(nbf, 'd') eold = 0 for iter in xrange(maxiter): Hoep = get_Hoep(b, H0, Gij) orbe, orbs = geigh(Hoep, S) D = mkdens(orbs, 0, nocc) Vhf = get2JmK(Ints, D) energy = trace2(2 * h + Vhf, D) + Enuke if abs(energy - eold) < tol: break else: eold = energy logging.debug("OEP AN Opt: %d %f" % (iter, energy)) dV_ao = Vhf - Vfa dV = matrixmultiply(transpose(orbs), matrixmultiply(dV_ao, orbs)) X = zeros((nbf, nbf), 'd') c = zeros(nbf, 'd') Gkt = zeros((nbf, nbf), 'd') for k in xrange(nbf): # This didn't work; in fact, it made things worse: Gk = matrixmultiply(transpose(orbs), matrixmultiply(Gij[k], orbs)) for i in xrange(nocc): for a in xrange(nocc, norb): c[k] += dV[i, a] * Gk[i, a] / (orbe[i] - orbe[a]) for l in xrange(nbf): Gl = matrixmultiply(transpose(orbs), matrixmultiply(Gij[l], orbs)) for i in xrange(nocc): for a in xrange(nocc, norb): X[k, l] += Gk[i, a] * Gl[i, a] / (orbe[i] - orbe[a]) # This should actually be a pseudoinverse... b = solve(X, c) logger.info("Final OEP energy = %f" % energy) return energy, orbe, orbs