Exemple #1
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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)
Exemple #2
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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)
Exemple #3
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    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
Exemple #4
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    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
Exemple #5
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    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
Exemple #6
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    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
Exemple #7
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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)
Exemple #8
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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
Exemple #9
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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)
Exemple #10
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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