CASINO manual - Theory of Condensed Matter

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USE GJASTROW (Logical) If set to T, the general Jastrow factor (under development) will be used. This Jastrow factor has to be defined in a parameters.casl file. The default is F. USE GPCC (Logical) If this is set to T then short-ranged functions will be added to the orbitals to ensure that the Kato cusp conditions are satisfied. USE JASTROW (Logical) Use a wave function of the Slater-Jastrow form, where the Jastrow factor exp(J) is an optimizable object that multiplies the determinant part in order to introduce correlations in the system. The Jastrow factor is read from the ‘JASTROW’ block in correlation.data (see Sec. 7.4.2). The form of casino’s Jastrow factor is described in Sec. 22. If use jastrow is F then the Slater wave function will not be multiplied by the Jastrow factor. USE ORBMODS (Logical) If use orbmods is set to T then the orbital-modification block in correlation.data will be read, and the modification functions will be added to the numerical atomic orbitals. This only applies if atom basis type is set to ‘numerical’, ‘gaussian’ or ‘slatertype’. See Secs. 7.4.5 and 7.4.6. To optimize the corresponding parameters, use opt orbitals. USE TMOVE (Logical If use tmove is T then the Casula nonlocal pseudopotential scheme [20] will be used in DMC. So-called ‘T -moves’ will be performed in order to give a DMC energy that is greater than or equal to the ground-state energy. This violates the detailed-balance principle at finite time steps, but greatly improves the stability of the DMC algorithm when nonlocal pseudopotentials are used. The advantages of T-moves are that they restores the variational principle and prevent population explosions; the disadvantages of T-moves are that the magnitude of the locality approximation is generally larger (although always positive), the time-step bias is worse, and they require an enormous amount of memory in systems with large numbers of particles. Because of these disadvantages, the default of use tmove is F and we tend *not* to use them unless we face stability issues. VIRTUAL NCONFIG, VIRTUAL NNODES, VIRTUAL NODE (Integers) Number of configurations, number of processors and node number in virtual parallel variance minimization. These parameters are not to be set manually. VM E GUESS (Physical) If vm use e guess is T then vm e guess should be supplied as an estimate of the ground-state energy. (Note that energy units should be supplied.) See Sec. 25.1. VM FILTER (Logical) This keyword activates filtering of configurations in variance minimization by making the weights (artificially) energy-dependent, i.e., W i = W (|E i − E ave |). This method uses two parameters: vm filter thres and vm filter width. See Sec. 25.1. VM FILTER THRES, VM FILTER WIDTH (Real) When limiting outlying configurations in variance minimization (by setting the vm filter flag to T), the maximum deviation from the average energy at which the (artificial) weight of a configuration W i = W (|E i −E ave |) is kept equal to unity is vm filter thres times the square root of the unreweighted variance. Outside this limit, the weight is brought to zero using a gaussian of width vm filter width times the square root of the unreweighted variance. By default, vm filter thres is 4.0 and vm filter width is 2.0. See Sec. 25.1. VM FORGIVING (Logical) Do not whinge about calculated configuration energies not agreeing with those read in. Recommended to be set to F. VM LINJAS ITS (Integer) vm linjas its specifies the maximum number of iterations to be performed if vm linjas method is ‘CG’, ‘SD’, ‘BFGS’, ‘CG MC’, ‘BFGS MC’ or ‘GN MC’. If vm linjas method is ‘MC’, ‘LM’, ‘CG MC’, ‘BFGS MC’, or ‘GN MC’ then it (also) specifies the number of line minimizations to be performed. See Sec. 25.2. Setting vm linjas its to 0 gives default behaviour, which is usually adequate. VM LINJAS METHOD (Text) vm linjas method specifies the method used to minimize the quartic least-squares function in the varmin-linjas optimization scheme. vm linjas method should be one of: ‘CG’ (conjugate gradients), ‘MC’ (Monte Carlo), ‘LM’ (line minimization), ‘SD’ (steepest descents), ‘BFGS’ (Broyden-Fletcher-Goldfarb-Shanno), ‘BFGS MC’ (BFGS and Monte Carlo), ‘CG MC’ (conjugate gradients and Monte Carlo), ‘GN’ (Gauss-Newton) or ‘GN MC’ (Gauss-Newton and Monte Carlo). (See Sec. 25.2). ‘BFGS’ is the default method, although in case of difficulty, it is worth trying ‘GN’. 54
VM REWEIGHT (Logical) If vm reweight is T then the reweighted variance-minimization algorithm will be used. If F then the unreweighted algorithm will be used. See Sec. 25.1. Unreweighted variance minimization is recommended. VM SMOOTH LIMITS (Logical) When set to T, the optimizing routine used in variance minimization is sent a smoothed version of the set of parameters. This only affects those which are to remain bounded, such as Jastrow cutoffs. The result is a set of parameters that can vary in the range (−∞, +∞), which is more convenient than ignoring out-of-range values without the minimizer knowing. A suitable hyperbolic function is used for mapping ‘limited’ values into ‘extended’ ones and vice versa. VM USE E GUESS (Logical) Setting this flag to T will cause the ‘variance’ in variance minimization to be evaluated using vm e guess in place of the average energy of the configuration set, in an attempt to combine energy minimization with variance minimization. Otherwise the least-squares function will simply be the variance of the configuration local energies. See Sec. 25.1. VM W MAX (Real) Maximum value that a configuration weight may take during reweighted variance minimization (i.e., when vm reweight is T). Set vm w max to 0 if you do not wish to limit the weights; otherwise it should be greater than 1. VM W MIN (Real) Minimum value that a configuration weight may take during reweighted variance minimization (i.e., when vm reweight is T). vm w min should have a value between zero and one. Note that the limiting is not applied if vm w max = 0. VMC AVE PERIOD (Integer) Number of consecutive local energies that are averaged together in VMC before writing them to the vmc.hist file. The only effect of this keyword is reduce the size of vmc.hist: the number of lines written in a VMC calculation is vmc nstep/(vmc ave period × number of processors). VMC DECORR PERIOD (Integer) Length of the inner decorrelation loop in VMC. The algorithm will perform vmc decorr period configuration moves between successive evaluations of the local energy (and other quantities to be averaged) in order to ensure the configurations that are used are not significantly correlated with each other. Setting vmc decorr period to a value greater than 1 should reduce the serial correlation of the data, but the length of the run will be increased. Typical values might be 3 or 4 for a pure VMC calculation, and ≥ 10 during a config-generation run for optimization or DMC (though this depends on the system). Note that setting the decorrelation period to a higher value in DMC configuration generation is less important than in wave function optimization, since the correlations will disappear as the DMC calculation evolves. The value of vmc decorr period is ignored during VMC equilibration. Note that vmc nstep refers to the number of moves at which energies are evaluated or configurations are written out; this is not affected by the value of vmc decorr period. Note that casino is able to automatically determine vmc decorr period to maximize the run efficiency. This is done by adding an extra set of moves after equilibration to compute an estimation of the correlation time of the local energies. The feature is enabled by setting vmc decorr period=0.”) VMC EQUIL NSTEP (Integer) Total number of equilibration steps in VMC; should normally be at least a few thousand. Equilibration is only performed if newrun=T, thus the value of vmc equil nstep is ignored on restarts. This is a single-processor quantity, that is, all processors run vmc equil nstep equilibration steps. The value of vmc decorr period is ignored during equilibration. VMC IONJUMP (Real) In the special case of nearly separated molecule fragments (e.g., for intermolecular forces) electrons may get trapped in the energetically less favourable fragment for a long time during a VMC run due to the large distance between the fragments. Setting vmc ionjump to a small, nonzero probability will cause the VMC routine to try a long-distance jump from one ion to another once in a while, improving the sampling of disjoint areas of the configuration space. Detailed balance is preserved. VMC METHOD (Integer) vmc method selects which version of VMC to use: (1) propose singleelectron moves at the accept/reject stage and evaluate configuration energies at the end of the configuration move; or, (3) propose entire configuration moves at the accept/reject stage and 55
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CASINO User’s Guide Version 2.13
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8.6 GAUSSIAN94/98/03/09 . . . . . .
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29.2 Fourier transformation of CASI
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1 Introduction casino is a computer
Page 9 and 10: 3.2 Legal stuff casino is given awa
Page 11 and 12: - Grossman-Mitas DMC-DFT molecular
Page 13 and 14: Your defined setup can then be perm
Page 15 and 16: - : perform compilation (default).
Page 17 and 18: 6 Introductory user’s guide: how
Page 19 and 20: ATOM BASIS TYPE The basis used to r
Page 21 and 22: ENVMC v0.60: Script to extract VMC
Page 23 and 24: Std. err. in the mean DMC energy (a
Page 25 and 26: Jastrow factor from each cycle of t
Page 27 and 28: V(x) Ψ init (x) τ{ t Ψ 0 (x) x T
Page 29 and 30: the energy becomes roughly constant
Page 31 and 32: many cores, time limits etc, which
Page 33 and 34: Set the verbosity level of the mach
Page 35 and 36: 6.7 How to run coupled DFT-DMC mole
Page 37 and 38: unqmcmd --startqmc=M Start the chai
Page 39 and 40: config.out This is the name under w
Page 41 and 42: ‘slater-type’: use Slater-type
Page 43 and 44: CUSTOM SPAIR DEP (Block) This input
Page 45 and 46: initial configurations come from DM
Page 47 and 48: DTDMC (Real) Time step for DMC run
Page 49 and 50: FORCES INFO (Integer) Controls the
Page 51 and 52: nucleus is assumed to lie at the or
Page 53 and 54: MOVIECELLS (Logical) If F then casi
Page 55 and 56: OPT MAXITER (Integer) Largest permi
Page 57 and 58: of G vectors and discards all those
Page 59: half a million cores, it may be des
Page 63 and 64: default this is 0 hartree. It shoul
Page 65 and 66: A very detailed specification of th
Page 67 and 68: -1 0 0 1 1 1 1 1 1 1 0 2 1 0 1 2 Pa
Page 69 and 70: cusp conditions; otherwise, only th
Page 71 and 72: Detailed information about each of
Page 73 and 74: |k| (outermost). Hence one can spec
Page 75 and 76: large and the wave function is near
Page 77 and 78: R(i) in atomic units 0.000000000000
Page 79 and 80: 2. The charge-density Fourier coeff
Page 81 and 82: c_767: [ 996 ] ... Compressed expan
Page 83 and 84: valence charges for each atom %%%%%
Page 85 and 86: 1988). This can be found online. An
Page 87 and 88: 1.3813695578425E+00 1.3957621401173
Page 89 and 90: PWSCF Method: DFT DFT Functional: u
Page 91 and 92: 0.125203784849961E-01 0.13042462855
Page 93 and 94: 3.3000000000000E+00 2.0000000000000
Page 95 and 96: Potential Number of grid points 200
Page 97 and 98: 9. Clearly, the total number of pos
Page 99 and 100: EBEST (DMC only) Best estimate of t
Page 101 and 102: Use G-vector set 1 Number of sets 2
Page 103 and 104: 1000.0 rho_a(G)*rho_b(-G) 16.0 4.12
Page 105 and 106: total weight must always be include
Page 107 and 108: The exporter does not currently wor
Page 109 and 110: 8.4.2 Generating gwfn.data files wi
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After successfully running properti
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% mv Test.FChk dna.Fchk run gaussia
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• By default, gaussian uses spin
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Routine Purpose qmc write Writes th
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not the case the defaults can be ch
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8.10 TURBOMOLE Website: www.turbomo
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• crysgen06/09, crystaltoqmc: The
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• quickblock: Simple reblocking u
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• In Movie Settings choose Trajec
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the move rejection probability is h
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This leads to the single-electron d
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In the UNR [19] scheme the modified
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13.7 Evaluating expectation values
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Population-control catastrophes sho
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where u k has the periodicity of th
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Although the constraint equations a
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18 Wave-function updating Consider
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19.2 Evaluating the nonlocal pseudo
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of a unit point charge at r j in ev
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19.4.3 1D Coulomb interaction Coulo
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To investigate whether the extrapol
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correlations, such as might be enco
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where n is the order of the expansi
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terms by definition, and it can be
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which is therefore independent of r
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where the local energy, E L , is E
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Another variant of variance minimiz
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The energy minimization method used
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valid. The first problem, which ari
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• Is emin min energy too high? Th
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It may be activated by setting vmc
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that the number of configuration mo
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• It is possible to use blip orbi
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0.5 0.5 0.0 particle 1 det 1 : 9 or
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The clearup twistav script can be u
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In the infinite system limit, the s
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Note that this has the k −2 diver
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• The effective time step, Eq. (3
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1 2 H He 1.00794 4.00260 3 4 5 6 7
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and the Dirac delta function is δ(
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33.2.2 Atomic densities K eywords:
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The spin-density matrix is a two-by
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33.3.3 Homogeneous and isotropic sy
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33.4 Structure factor and spherical
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33.5 One-body density matrix, two-b
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[ where the approximation ρ (1)T
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The figure shows the localization l
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with F HFT mix = − F P mix = −
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The input keyword to activate the c
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To each walker r j , we assign a li
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37 Magnetic fields and the fixed-ph
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38 Analysis of the performance of C
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the orbitals, α = 2 [11]. The use
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39.2 Implementation basics and perf
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• Use ‘endif’ and ‘enddo’
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• Evidence of testing on serial a
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B Appendix 2: Automatic testing of
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• Delete any eepot.data and densi
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* "Generic" CASINO_ARCHs are intend
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- ‘head -n 1 /etc/redhat-release
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for a single job in an ensemble of
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inary executable. CASINO does not r
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otherwise. The following tags are o
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[2] V.R. Saunders, R. Dovesi, C. Ro
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[50] W. Janke, Statistical Analysis
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CASINO manual - Theory of Condensed Matter

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