CASINO manual - Theory of Condensed Matter

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%block kpoints_list 0.25 -0.25 -0.25 0.25 0.25 -0.25 0.25 0.25 0.25 0.25 -0.25 0.25 0.25 0.25 0.25 0.25 %endblock kpoints_list This is a 2 × 2 × 2 k-point mesh offset so that Γ is exactly in between the grid points, with only one out of each ±k being given, and equal weight being assigned to each k point in the DFT calculation. The symmetry generate flag should be given in seedname.cell. 4. Run a castep single-point energy calculation (not geometry optimization, etc.) using castep 〈seedname〉. 5. Then run the castep2casino converter, which is part of the castep distribution using castep2casino 〈seedname〉. 15 6. Rename seedname.casino as pwfn.data. 7. The pwfn.data can be read by casino, but it’s usually best to convert to a blip basis by running the blip program. (See Sec. 9.) 8.4 CRYSTAL [See ~/CASINO/utils/wfn converters/crystal 9x/, /crystal 03/, /crystal 06 and /crystal 09.] 8.4.1 The CRYSTAL program crystal is a commercially available quantum-mechanical package which is able to calculate the electronic structure of both molecules and systems with periodic boundary conditions in 1, 2 or 3 dimensions (polymers, slabs or crystals) using either HF or DFT. The latest version of the program was written by Roberto Dovesi, Vic Saunders, Carla Roetti, Roberto Orlando, Nic Harrison, Claudio Zicovich-Wilson, Klaus Doll, Bartolomeo Civalleri, Ian Bush, Philippe D’Arco, Miquel Llunell and F. Pascale. See www.tcm.phy.cam.ac.uk/~mdt26/crystal.html and the various links from there for more information. casino supposedly supports the official releases crystal95, crystal98, crystal03, crystal06 and crystal09 (but not 88 or 92). With the now very obsolete crystal95 or crystal98 you must use a separate utility crysgen98 — included with the casino distribution—which transforms the contents of various crystal temporary Fortran files into a casino gwfn.data file. crystal03 was supposed to contain a facility to write out a casino gwfn.data file directly. The necessary routines were written by MDT following a specification agreed by the Daresbury authors of crystal but its incorporation into crystal was then vetoed by the Torino group. MDT was then asked to change the routines into a separate utility, but necessary information regarding the crystal source code was not available. The practical upshot of this is that casino is only supported in MDT’s private version of crystal03 which he is not allowed to distribute. Best to use crystal06 or crystal09 instead. crystal06 is able to write out all the information required by external programs but as this is not specific to casino a utility crysgen06 is required to convert the data into casino gwfn.data format. crystal09 is able to write out all the information required by external programs but as this is not specific to casino a utility crysgen09 is required to convert the data into casino gwfn.data format (the size of the overlap matrix in the API was changed in going from 06 to 09 for some reason, hence the different utility). If you want to use pseudopotentials with crystal you can use the Trail-Needs ones on the casino website, which are given in the crystal format. For some of these a Gaussian basis set in the appropriate format which is optimized with respect to the pseudopotential is included in the ‘Further data’ column. 15 If you are using an old version of castep then you will need to insert the line ‘continuation : 〈seedname〉’ in the seedname.param file before running castep2casino. 102
8.4.2 Generating gwfn.data files with CRYSTAL95/98 These early versions of crystal are absolutely not designed to communicate with other programs so we will need to jump through some hoops in order to get things to work. Basically, MDT’s crysgen98 utility is used to convert the output of crystal95 or crystal98 into a gwfn.data file readable by casino. We will assume in what follows that you know how to use crystal. You need to run the program using the runcrystal script, which lives in ~/CASINO/wfn converters/crystal9x/run script/, using the -qmc flag as an argument (this should be set up automatically for you during utilities compilation). The publicly available run script on MDT’s crystal website does not contain this flag, so you need to use the script included with casino instead. You may need to change some environment variable definitions in the run and crysgen98 scripts to get them to work properly on your system. If you want to use your own copy of crystal95 or crystal98 to generate QMC wave functions, you will need to make some minor modifications to the source code (see the accompanying ~/CASINO/wfn converters/crystal to qmc/README CHANGES file). If you are working in Cambridge, you can use the programs that have already been so modified by MDT—please ask. (NOTE: 4/2003—the above changes involve turning off the use of symmetry in k space—for some metallic calculations this seems to cause a problem (Gilat net?) unless you also manually turn off all symmetry in the input file with the keyword symmremo. This is unlikely to be fixed in the future.) crystal will produce three binary files in the scratch directory you define in the run script—namely fort.12 (basis set, geometry, common variables), fort.10 (orbital coefficients) and fort.30 (eigenvalues). These files would normally be deleted at the end of a crystal run. Including the -qmc flag as an argument to the run script means these files will be grabbed and renamed as silicon.f12, silicon.f10 and silicon.f30 (or whatever). They will be kept in the scratch directory since they can become very large. Sit in the directory where these three files live and type crysgen98. This script will run the crystaltoqmc program, which will ask you some questions and then generate the gwfn.data file. crysgen06/09 will ask you for the size of the Monkhorst–Pack k-point net in the crystal calculation, and the desired size of supercell in the QMC calculation. These need not be the same (if not, you are ‘plucking’ to use the local vernacular), but the former must be divisible by the latter. For example, a 12×12×12 MP net in crystal will allow you to generate gwfn.data for 1×1×1, 2×2×2, 3×3×3, 4×4×4 and 6×6×6 supercell cases. Note that it is desirable to carry out the calculation on a higher density k-point grid than you actually need so that the orbital coefficients are calculated accurately. Note that for polymer and slab calculations the last one and two numbers in the MP net and supercell specifications should be 1 to reflect the fact that the system is not periodic in those dimensions. For example, polymer (12×1×1 −→ 1×1×1, 2×1×1, 3×1×1, 4×1×1, 6×1×1) slab (12×1×1 −→ 1×1×1, 2×2×1, 3×3×1, 4×4×1, 6×6×1). For molecular calculations, just imagine you have a 1×1×1 MP net. So, to summarize, to produce gwfn.data from the crystal input file dna: % run -qmc dna The -qmc flag invokes generation of relevant QMC files in temp. % cd /temp/mdt . . . or whatever the temp directory is called in your crystal runscript. % crysgen06 or % crysgen09 Then answer the questions. % mv gwfn.data ~ ; rm dna.* Then run casino. 8.4.3 Generating gwfn.data files with CRYSTAL03 NOTE: THE FOLLOWING INSTRUCTIONS WILL NOT WORK WITH THE STANDARD RELEASE OF CRYSTAL03—SEE DISCUSSION ABOVE. THE BEST WAY AROUND THIS NOW IS TO USE CRYSTAL06/09. The gwfn.data file can be generated directly using the crystal03 properties program. 103
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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
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
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: The exporter does not currently wor
Page 111 and 112: After successfully running properti
Page 113 and 114: % mv Test.FChk dna.Fchk run gaussia
Page 115 and 116: • By default, gaussian uses spin
Page 117 and 118: Routine Purpose qmc write Writes th
Page 119 and 120: not the case the defaults can be ch
Page 121 and 122: 8.10 TURBOMOLE Website: www.turbomo
Page 123 and 124: • crysgen06/09, crystaltoqmc: The
Page 125 and 126: • 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
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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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