CASINO manual - Theory of Condensed Matter

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singular points of the wave functions, nor is it a solution for populations that get trapped in high-energy states. Be careful about this option when you do not know the reason for the population problems in the first place. MAGNETIC FIELD (Logical) Apply an external magnetic field using the magnetic vector potential specified in expot.data. See Sec. 37. MAKEMOVIE (Logical) Plot the particle positions every movieplot moves (see Sec. 11). MANUAL INTERACTION (Block) When interaction is set to ‘manual’, this block is used to specify the form and parameters of the desired interaction. The format is either square_well Height : -2.0 Width : 3.0 or poschl_teller Mu : 12 V_0 : -1.0 or hard_sphere D : 0.88 where ‘Height’, ‘Width’, V 0 , µ and D are parameters describing the shape of the potential. A negative ‘Height’ or V 0 implies a potential well. For hard-sphere particles, D is the diameter. See Sec. 20. MAX CPU TIME (Physical) If the CPU time elapsed since the start of a QMC simulation exceeds max cpu time and a suitable point in the algorithm is reached, then casino will halt gracefully. This should make it easier to carry out, e.g., multiple DMC runs on a computer with a queueing system, particularly when used with the --continue or --auto-continue options of runqmc. Note that in DMC, if checkpoint=0 in input and there is a job time limit, it is strongly recommended that max cpu time is used to ensure the config.out file is written out if the required CPU time is longer than the time limit. max cpu time is a physical parameter with dimensions of time, and the units can be specified as, e.g., 1 day, 24 hr, 1440 min, or 86400 s. See also the max real time keyword. MAX REAL TIME (Physical) If the wall-clock time elapsed since the start of a QMC simulation exceeds max real time and a suitable point in the algorithm is reached, then casino will halt gracefully. This should make it easier to carry out, e.g., multiple DMC runs on a computer with a queueing system, particularly when used with the --continue or --auto-continue options of runqmc. Note that in DMC, if checkpoint=0 in input and there is a job time limit, it is strongly recommended that max real time is used to ensure the config.out file is written out if the required time is longer than the time limit. max real time is a physical parameter with dimensions of time, and the units can be specified as, e.g., 1 day, 24 hr, 1440 min, or 86400 s. See also the max cpu time keyword. MAX REC ATTEMPTS (Integer) This is the maximum number of times that DMC will attempt to restart a block if it continues to encounter population-explosion catastrophes. Relevant only if the dmc trip weight keyword is set to a nonzero value. See the discussion in Sec. 13.9 for more details. MOLGSCREENING (Logical) Toggle on and off the use of screening in Gaussian basis set calculations of molecules, i.e., the division of space into boxes and the preparation of lists of which Gaussian basis functions have a significant weight in each box. The use of screening should speed up the calculation of large molecules. The screening information can take up a reasonable amount of memory; hence the existence of this keyword. MOM DEN (Logical) If set to T the momentum density will be accumulated. Exclusively for HEGs at the moment. 46
MOVIECELLS (Logical) If F then casino will plot the unit cell when making a movie; if T then nearest-neighbour cells in the (x, y)-plane will also be written (see Sec. 11). MOVIENODE (Integer) Plot the particle positions on processor movienode (see Sec. 11). MOVIEPLOT (Integer) Plot the particle positions every movieplot moves (see Sec. 11). MPC CUTOFF (Physical) mpc cutoff is the energy cutoff for G-vectors used in (a) the FFT of the MPC interaction and (b) the FFT of the one-particle density required when generating the mpc.data file. The program will suggest a value for mpc cutoff if the existing value is unsuitable, or if the user inputs a value of zero. The default is 30 a.u. See Sec. 19.4.4. NED (Integer) For real systems containing atoms, ned is the total number of spin-down electrons referenced by the many-body wave function (for periodic systems, this is the number of spindown electrons in the simulation cell, rather than the underlying primitive cell). The number of spin-up electrons is given by the keyword neu. Note that in the presence of addition or subtraction excitations, ned refers to the state of the system AFTER the required number of electrons have been added or removed. For model electron(-hole) phases such as the HEG, set ned to zero and use the free particles block to define the number of spin-down electrons. NEIGHPRINT (Integer) neighprint= n will generate a printout of the first n stars of neighbours of each atom in the primitive cell, with the relevant interatomic distances given in both Ångstrom and a.u. If n = 0 or if you have an atom-free electron or electron–hole fluid phase, then the keyword has no effect. Note that activating cusp corrections when using a Gaussian basis (the default) will trigger a neighbour analysis irrespective of the value of this keyword. NEU (Integer) For real systems containing atoms, neu is the total number of spin-up electrons referenced by the many-body wave function (for periodic systems, this is the number of spin-up electrons in the simulation cell, rather than the underlying primitive cell). The number of spindown electrons is given by the keyword ned. Note that in the presence of addition or subtraction excitations, neu refers to the state of the system AFTER the required number of electrons have been added or removed. For model electron(-hole) phases such as the HEG, set neu to zero and use the free particles block to define the number of spin-up electrons. NEWRUN (Logical) Specifies whether a new run or a continuation of an old one is to be performed: T: (VMC) vmc equil nstep Metropolis steps are performed on a set of randomly generated configurations before accumulation of statistics begins.; (DMC) A set of VMC configurations is read from a config.in file and the initial best estimate of the energy EBEST is calculated as the mean energy of these configurations. In the special case of dmc reweight configs=T, config.in may also contain DMC configurations which are reweighted to a new wave function and EBEST shifted by the current energy difference between the wave functions.; F: (VMC) Continuation of an old run. A set of old (and presumably equilibrated) electron positions are read from a config.in file, and no Metropolis equilibration steps are performed before accumulation of statistics.; (DMC) Continuation of an old run. A set of DMC configurations is read from a config.in file and EBEST is not recomputed but taken to have the value written on the end of the config.in file (presumably by a previous DMC run, either equilibration or accumulation). NHD (Integer) Like nhu, but for spin-down particles. NHU (Integer) Number of spin-up fermions other than electrons in real systems. For example, if you are interested in positronic molecules then nhu should be set to 1, and the up-spin positron (‘spin’ 3) should be defined appropriately in the particles block. Likewise for muonic systems. At present only the Gaussian routines can be used to return orbitals for species other than electrons. (There exists a modified version of the gaussian code that can be used to generate orbitals for positronic molecules.) If you want to use a different basis or study muons or something then you will need to make the appropriate changes first. For model systems such as electron-hole gases, etc., please use the free particles block to define the number of spin-up holes. 47
Page 1 and 2: CASINO User’s Guide Version 2.13
Page 3 and 4: 8.6 GAUSSIAN94/98/03/09 . . . . . .
Page 5 and 6: 29.2 Fourier transformation of CASI
Page 7 and 8: 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: nucleus is assumed to lie at the or
Page 55 and 56: OPT MAXITER (Integer) Largest permi
Page 57 and 58: of G vectors and discards all those
Page 59 and 60: half a million cores, it may be des
Page 61 and 62: VM REWEIGHT (Logical) If vm reweigh
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
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1000.0 rho_a(G)*rho_b(-G) 16.0 4.12
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total weight must always be include
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The exporter does not currently wor
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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
Page 225 and 226:
• 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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