casino_prepare

Copy a calculation into a new directory and write the input for the next run in it.

This is how a calculation becomes the next one: optimise a wave function, then prepare a vmc_dmc directory beside it; halve the timestep into another; change the target weight into a third. A copy rather than an edit, because a number whose input was overwritten in place can no longer be reproduced, and because casino_run refuses a directory that already holds a run -- rightly.

What is copied is what a calculation is given and never what a run produced: input, the orbital file, correlation.data, parameters.casl, the pseudopotentials, and config.in (which a dmc-only or opt runtype reads as an input). Not out, not the .hist files, not config.out. A symlinked orbital file is copied by content, so the new directory stands on its own.

runtype: the runtype the new directory is for -- vmc, vmc_opt, opt, vmc_dmc, vmc_dmc_equil, dmc_dmc, dmc_equil, dmc_stats. Every keyword that runtype needs and the source input does not set is filled from a working default; every keyword the source does set is kept, so the electron count, the basis and any hand tuning survive. Leave it empty to keep the source's runtype and only apply overrides. overrides: keywords to set, as {name: value}, and they win over both the source and the defaults. A null value deletes the keyword; a value containing newlines is written as a %block (that is how opt_plan and npcell are set). Values are written verbatim, so booleans are 'T' and 'F' as CASINO spells them. jastrow: the terms of a blank Jastrow factor to write into the new directory -- ['u', 'chi', 'f'] for the usual one, ['u'] for a system with no atoms. This is for the first calculation of a chain, the one whose directory holds an orbital file and nothing else: use_jastrow : T needs a correlation.data, no CASINO utility writes one, and the manual's own instruction is to copy an example and delete its numbers by hand. Every coefficient starts at zero, which is what the first optimisation cycle is for. Leave it unset when the source already has a correlation.data; asking for both is refused, because a blank Jastrow would discard an optimised one. Finite systems only so far: a periodic Jastrow wants a P term, whose stars come from CASINO's own make_p_stars. backflow: the terms of a blank backflow function, in the same file -- ['eta', 'mu', 'phi'] for the usual one. It goes with backflow : T in the input, and the two blocks are written together for a calculation that wants both. The electron-nucleus cusp type of each set is not a setting: it is read off the pseudopotentials in the directory, 1 for a bare nucleus and 0 behind a pseudopotential, because CASINO believes the flag without checking it. No AE CUTOFFS section is written -- it is optional, and CASINO chooses the lengths itself. jastrow_settings: the shape of both blocks, where the defaults are not wanted. Jastrow: trunc_order (3), n_u (8), n_chi (8), n_f_en (3), n_f_ee (3), spin_dep_u (1), spin_dep_chi (0), spin_dep_f (1), cusp_chi (0), cutoff_u / cutoff_chi / cutoff_f (0, which CASINO reads as "use your own default"), no_dup_u (0), no_dup_chi (0), optimizable (1, the cutoffs). Backflow: bf_trunc_order (3), n_eta (9), n_mu (9), n_phi_en (3), n_phi_ee (3), spin_dep_eta (1), spin_dep_mu (0), spin_dep_phi (1), cutoff_eta / cutoff_mu / cutoff_phi (0), irrotational (0), cusp_bf (-1, meaning derive it from the pseudopotentials).

Nothing is written unless the result would actually run: the keyword combinations CASINO only rejects at run time are checked first (an optimisation sample smaller than the DMC target weight, opt_backflow without backflow, a missing mandatory keyword), and so is the presence of every file the input tells CASINO to read. A refusal names the problems and creates no directory. What is legal but probably unintended -- a dtdmc still at CASINO's placeholder default, dmc_stats_nstep not divisible by its block count, keywords left over from the runtype this was copied from -- comes back in warnings and does not stop it.