CASINO manual - Theory of Condensed Matter

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must be specified (note that both members of a ±k pair must be given), and complex wf must be T in the input file. The offsets to the grid of k vectors are chosen randomly. By default the script uses runqmc to run the casino calculations. If the script is to be used on a machine with a queueing system then the ‘-batch’ flag should be set and the command for running casino should be specified with, e.g., ‘-casino "runqmc --nproc=4 --walltime=1h5m"’. The script doesn’t currently let you submit the castep jobs to a queue, but the castep runs are relatively quick. The number of twists to use is specified using the ‘-ntwist’ flag (default 12 at the time of writing). For more information on available options, type twistav castep -help. The clearup twistav script can be used to clear up the output from a castep twist-averaging run. 28.3.4 Monte Carlo twist averaging for real systems using CASINO and PWSCF This is automated with the twistav pwscf utility. The support provided by this script is currently more advanced than its castep equivalent since it uses the standard casino architecture system (meaning it should run automatically on any system, batch or otherwise) and the full range of run time options are available. pwscf itself by default works with binary bwfn.data.b1 files which obviates the need for using huge bwfn.data files as in castep, and no multi-step conversions (involving e.g., castep2casino and blip utilities) are required. Usage: twistav_pwscf [--help --nproc_dft=I --splitqmc[=N] --startqmc=M --dft_only/--qmc_only --ntwist=L [] This script is used to automate the collection of twist-averaged data using casino and the pwscf DFT code (part of the Quantum espresso package, available at www.quantum-espresso.org). pwscf must be version 4.3 or later. This script works by repeatedly calling the runpwscf and runqmc scripts which know how to run pwscf/casino on any individual machine. With the exception of those listed above, almost all optional arguments to this script are the same as for runpwscf/runqmc and are passed on automatically to these subsidiary run scripts (the --background/-B option is also used by twistav pwscf, and for the same purpose). Type ‘runpwscf --help’ or ‘runqmc --help’ to find out what these options are. The short list of optional flags specific to twistav pwscf are described below. It is assumed that pwscf lives in $HOME/espresso and casino lives in $HOME/CASINO. There are override options available if this is not the case. If you are running on a multi-user machine with an account to be charged for the calculations, you might consider aliasing twistav pwscf as alias twistav pwcf="twistav pwscf --user.account=CPH005mdt " or whatever. In general you should do something like the following: Setup the pwscf input (‘in.pwscf’) and the casino input (‘input’, etc., but no wave function file) in the same directory. For the moment we assume you have an optimized Jastrow from somewhere. Have the pwscf setup as calculation = scf with both nosym and noinv (system section) set to T and verbosity (control section) to high. The required k point info is not printed in output without the latter. In your casino input file, complex wf must be T. The twistav pwscf script will then run pwscf once to generate ‘ntwist’ xwfn.data files (ntwist default = 12, or change with optional argument --ntwist=xx), then it will run casino on each of the xwfn.data. The casino out files, xwfn.data files, config.out and vmc.hist/dmc.hist files will be renamed with an appropriate integer suffix. The calculation can be run through pwfn.data, bwfn.data or bwfn.data.b1 formats as specified in the pw2casino.dat file (see casino and pwscf documentation). When pwscf is upgraded to produce new-format bwfn.data.bin files, then this script will need to be changed - ask MDT to do so. If you wish to do the (fast) DFT wave function generation calculations and the (slow) QMC calculations on different machines, for example to avoid batch queue waiting time, then use the --dft only option to generate the full set of xwfn.data files, transfer these to the more powerful machine, then run on that using the --qmc only option—see below. 172
The clearup twistav script can be used to clear up the output from a pwscf twist-averaging run. Default behaviour of twistav pwscf (on all machines): Note: in the following ntwist is 12, or the value of the optional argument --ntwist, while xwfn.data refers to whatever wave function file is specified in the pw2casino.dat file (either bwfn.data.b1 [default], bwfn.data or pwfn.data). For a complete twist-averaging run, the following steps are performed in sequence: (A) pwscf generates ntwist xwfn.data.$ files, where $ is a sequence number from 1 to ntwist. Each succeeding run will have a different twist. (B) casino runs a full VMC or DMC run on each of the xwfn.data. On batch queue systems, twistav pwscf will by default do two batch script submissions, the first— handled by the runpwscf script—executing step (A), and the second—handled by the runqmc script— executing step (B). In principle, this wastes some unnecessary time (the time spent waiting for the QMC batch script to start) but this is unavoidable if twistav pwscf uses separate runpwscf and runqmc scripts to handle the DFT xwfn generation and QMC calculations. This may be changed in the future, if anyone can be arsed. Note that all calculations will be done on the number of cores requested on the command line (with the --nproc/-p flag) irrespective of whether they are DFT or QMC calculations. You may override this for the DFT calculations by using the --nproc dft flag to twistav pwscf. Modifications to default behaviour (on all machines) (1) twistav_pwscf --dft_only : execute only step (A), generating ntwist xwfn.data.$ files. (2) twistav_pwscf --qmc_only : execute only step (B). This requires that the ntwist xwfn.data.$ files already exist; if they don’t the script will whinge and die. (3) twistav_pwscf --startqmc=M : Start the chain of QMC runs with file xwfn.data.M . Modifications to default behaviour (batch machines only) On batch machines, there is an additional complication due to the walltime limits on particular queues which may require full twist-averaging runs to be split into sections. The following method may be used to do this. (4) twistav_pwscf --splitqmc=N : Split step B into N separate batch script submissions. If no value is supplied [--splitqmc] the run will be split into two. Example: ntwist=13, and twistav pwscf --splitqmc=4 will result in four step B batch submissions with 3, 3, 3, 4 twists. Note there is no facility for splitting step A into sections, i.e., all DFT wave function generation runs will always be run in a single batch script submission. This is because we assume the DFT runs are fast and you have adequate job time limits. If this is not the case then simply do multiple sets of twistav pwscf runs. 29 Finite-size correction to the kinetic energy 29.1 Finite-size correction due to long-ranged correlations Consider a periodic system of N particles. Suppose there are N s species present, each with mass m α and charge q α , and let N α be the number of particles of type α. Let r iα be the position vector of the ith particle of type α. Let the simulation supercell have volume Ω. 173
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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
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3.2 Legal stuff casino is given awa
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- Grossman-Mitas DMC-DFT molecular
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Your defined setup can then be perm
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- : perform compilation (default).
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6 Introductory user’s guide: how
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ATOM BASIS TYPE The basis used to r
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ENVMC v0.60: Script to extract VMC
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Std. err. in the mean DMC energy (a
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Jastrow factor from each cycle of t
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V(x) Ψ init (x) τ{ t Ψ 0 (x) x T
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the energy becomes roughly constant
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many cores, time limits etc, which
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Set the verbosity level of the mach
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6.7 How to run coupled DFT-DMC mole
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unqmcmd --startqmc=M Start the chai
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config.out This is the name under w
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‘slater-type’: use Slater-type
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CUSTOM SPAIR DEP (Block) This input
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initial configurations come from DM
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DTDMC (Real) Time step for DMC run
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FORCES INFO (Integer) Controls the
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nucleus is assumed to lie at the or
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MOVIECELLS (Logical) If F then casi
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OPT MAXITER (Integer) Largest permi
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of G vectors and discards all those
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half a million cores, it may be des
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VM REWEIGHT (Logical) If vm reweigh
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default this is 0 hartree. It shoul
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A very detailed specification of th
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-1 0 0 1 1 1 1 1 1 1 0 2 1 0 1 2 Pa
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cusp conditions; otherwise, only th
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Detailed information about each of
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|k| (outermost). Hence one can spec
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large and the wave function is near
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R(i) in atomic units 0.000000000000
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2. The charge-density Fourier coeff
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c_767: [ 996 ] ... Compressed expan
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valence charges for each atom %%%%%
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1988). This can be found online. An
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1.3813695578425E+00 1.3957621401173
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PWSCF Method: DFT DFT Functional: u
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0.125203784849961E-01 0.13042462855
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3.3000000000000E+00 2.0000000000000
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Potential Number of grid points 200
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9. Clearly, the total number of pos
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EBEST (DMC only) Best estimate of t
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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
Page 127 and 128: • In Movie Settings choose Trajec
Page 129 and 130: the move rejection probability is h
Page 131 and 132: This leads to the single-electron d
Page 133 and 134: In the UNR [19] scheme the modified
Page 135 and 136: 13.7 Evaluating expectation values
Page 137 and 138: Population-control catastrophes sho
Page 139 and 140: where u k has the periodicity of th
Page 141 and 142: Although the constraint equations a
Page 143 and 144: 18 Wave-function updating Consider
Page 145 and 146: 19.2 Evaluating the nonlocal pseudo
Page 147 and 148: of a unit point charge at r j in ev
Page 149 and 150: 19.4.3 1D Coulomb interaction Coulo
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Page 153 and 154: correlations, such as might be enco
Page 155 and 156: where n is the order of the expansi
Page 157 and 158: terms by definition, and it can be
Page 159 and 160: which is therefore independent of r
Page 161 and 162: where the local energy, E L , is E
Page 163 and 164: Another variant of variance minimiz
Page 165 and 166: The energy minimization method used
Page 167 and 168: valid. The first problem, which ari
Page 169 and 170: • Is emin min energy too high? Th
Page 171 and 172: It may be activated by setting vmc
Page 173 and 174: that the number of configuration mo
Page 175 and 176: • It is possible to use blip orbi
Page 177: 0.5 0.5 0.0 particle 1 det 1 : 9 or
Page 181 and 182: In the infinite system limit, the s
Page 183 and 184: Note that this has the k −2 diver
Page 185 and 186: • The effective time step, Eq. (3
Page 187 and 188: 1 2 H He 1.00794 4.00260 3 4 5 6 7
Page 189 and 190: and the Dirac delta function is δ(
Page 191 and 192: 33.2.2 Atomic densities K eywords:
Page 193 and 194: The spin-density matrix is a two-by
Page 195 and 196: 33.3.3 Homogeneous and isotropic sy
Page 197 and 198: 33.4 Structure factor and spherical
Page 199 and 200: 33.5 One-body density matrix, two-b
Page 201 and 202: [ where the approximation ρ (1)T
Page 203 and 204: The figure shows the localization l
Page 205 and 206: with F HFT mix = − F P mix = −
Page 207 and 208: The input keyword to activate the c
Page 209 and 210: To each walker r j , we assign a li
Page 211 and 212: 37 Magnetic fields and the fixed-ph
Page 213 and 214: 38 Analysis of the performance of C
Page 215 and 216: the orbitals, α = 2 [11]. The use
Page 217 and 218: 39.2 Implementation basics and perf
Page 219 and 220: • Use ‘endif’ and ‘enddo’
Page 221 and 222: • Evidence of testing on serial a
Page 223 and 224: B Appendix 2: Automatic testing of
Page 225 and 226: • Delete any eepot.data and densi
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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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