Configuration reference

A run is described by three sections: the problem ([dataassim] for assimilation, [optim] for optimisation), the ensemble, and the simulator ([fwdsim] is accepted as its name too). They can be written in TOML, YAML or the legacy .pipt/.popt text format, or built as Python dictionaries in a script. Whichever way they arrive, input_output.config normalises them once -- canonical key names, booleans for flags, dictionaries for sub-blocks -- and everything downstream reads that one form. pet validate my_config.toml reports what is missing, by section and key, and points out keys nothing in PET reads.

Flags accept true/false, yes/no and the Python booleans. A key marked presence is on when it is present at all, whatever its value.

[dataassim]

The problem

Key	Meaning	Default
scheme	Algorithm: esmda, es, enkf, lmenrml, gnenrml. pipt.available_schemes() lists every (scheme, analysis) pair.	required
analysis	Analysis flavour the scheme runs: approx, full, subspace (all schemes); subspace2 (ES-MDA, LM-EnRML, GN-EnRML); margis (GN-EnRML). subspace2 solves for the ensemble transform directly and uses the analytic data covariance, so it reads neither energy nor iteration.energy.	approx
energy	Truncation energy of the SVD in ES-MDA, ES and EnKF; a fraction, or a percentage when greater than 1. The iterative schemes read iteration.energy.	0.98
emp_cov	The variance file holds an ensemble of observation errors; the analyses use that empirical covariance. Flag.	off

Observed data

Key	Meaning	Default
data	Observations: a .csv, .pkl or .npz file with one row per report label and one column per data type. A cell may name a .npz file holding a vector (seismic). truedata is the older spelling.	required
datavar	Variance file on the same geometry. Each cell is ['abs', v], ['rel', percent], ['emp', ensemble] or ['cd', covariance.npz]. var is the older spelling.	required
obsname	Name of the report-label index (times, dates, steps). Not needed when data is a dict carrying index_name.	required
datatype	Data types to assimilate. Normally given in the simulator section and copied here.	from the data file
assimindex, truedataindex	Derived from the data file at load time; a value written here is replaced.	derived
scale_data	Max-min scale observations and predictions per data type before the analysis. Flag.	off
scale	[types, factor]: multiply the predictions of the named data types by factor.	none
remove_outliers	Replace members whose normalised misfit is more than four standard deviations from the mean after every forecast. Presence.	off
actnum	.npz with an actnum mask, used by the iterative schemes and QA/QC to map a field back to the grid.	none

Iteration (lmenrml, gnenrml): the [dataassim.iteration] block

Key	Meaning	Default
max_iter	Number of update iterations. The prior forecast is not one of them.	required
data_misfit_tol	Stop when the relative change of the mean data misfit is below this.	0.01
energy	Truncation energy of the SVD; a fraction, or a percentage when greater than 1.	0.95
max_inner_iter	Attempts one iteration may make (tightening the control after each rejected step) before giving up.	10
lambda	LM-EnRML: initial damping. auto sizes it from the prior misfit.	10
lambda_max, lambda_min	LM-EnRML: bounds on the damping; reaching lambda_max stops the run.	1e10, 0.01
lambda_factor	LM-EnRML: factor the damping is divided (accepted step) or multiplied (rejected step) by.	5
gamma	GN-EnRML: step length. auto starts at 0.1.	0.2
gamma_max, gamma_factor	GN-EnRML: bound and update factor for the step length.	1.0, 2.0

ES-MDA: the [dataassim.mda] block

Key	Meaning	Default
tot_assim_steps	Number of inflated assimilation steps; one update each.	required
inflation_param	Inflation factor per step (a list) or one factor for all. The inverses must sum to 1.	tot_assim_steps for every step

Localization: the [dataassim.localization] block

name selects the strategy; pipt.localization.available_localizations() lists them, register_localization adds one. All strategies take field (grid dimensions as a list of integers) and an optional actnum (.npz mask).

A block that gives no name is still understood: the mode is inferred from the keyword that used to select it — autoadaloc, localanalysis or dist_loc (as a key or as a bare value), a .p/.pkl mask file for distance_loc, and none of them for the parallel update. An explicit name always wins.

name	Keys	Meaning
autoadaloc	threshold (adaptive, fixed, universal), cutoff, type (hard, soft, sigm), projection (rank-r, ensemble), parameters	Auto-adaptive localization from the correlations the ensemble itself shows. cutoff is how many noise standard deviations a correlation must clear (default 0.3); it is also read from nstd, or from the value of autoadaloc itself.
distance_loc	taper_func (gaspari_cohn, furrer_bengtsson, region), entries (list of rows or a .csv)	Distance-based tapering around each datum: per entry a data type, report label, parameter, radius, anisotropy and vertical range.

localanalysis and the parallel update are not supported: both need per-subset observation machinery the scheme rewrite replaced, and naming either raises a ConfigError saying so. Use distance_loc or autoadaloc instead.

Seismic compression: the [dataassim.compress] block

Observed vintages named in compress_data are wavelet-compressed when read, and every prediction of that data type is reduced to the same leading coefficients as it enters the prediction matrix.

Key	Meaning
compress_data	Data type (or list) to compress.
dim	Grid dimensions of a vintage.
mask	One .npz (key mask) per vintage; a missing file means all cells active.
level, wname	Wavelet decomposition level and PyWavelets wavelet name (db2).
threshold_rule, th_mult, use_hard_th, keep_ca	universal or bayesian thresholding, its multiplier, hard vs soft thresholding, whether the approximation coefficients are kept.
inactive_value, order, min_noise, colored_noise	Fill value outside the mask, flatten order (C/F), noise floor per vintage, per-subband noise estimate.
use_ensemble	Not supported; refused with the reason.

post_process_forecast (flag) additionally divides sim2seis data types by the factor in scale_results.pkl, when that file is present.

Restart

Key	Meaning	Default
restartsave	Write a checkpoint after the prior forecast and every accepted iteration. Flag.	off
restart	Resume from the checkpoint instead of starting. Flag.	off
restart_file	Path of the checkpoint. restartfile is the older spelling.	<scheme>_restart.pkl

A resumed run continues the interrupted one exactly: the checkpoint carries the loop's bookkeeping, the scheme's state and the ensemble's state, prior, forecast and random stream.

Output

Key	Meaning	Default
savefolder	Folder for results. save_folder is the older spelling.	Results
nosave	Write no result files at all. Presence.	off
savedata	Attribute names saved per iteration to assimilation_result_{i}.npz (iteration 0 is the prior); state expands to one array per variable. analysisdebug is the deprecated spelling.	none
iterinfo	Python modules (name.py) whose main(scheme) runs after the prior and every accepted iteration.	none
obsvarsave	Also save the observed data and variance frames as obs_data.pkl and obs_var.pkl. Flag.	off
qa, qc	Run quality-assurance plots / quality-control statistics after the prior and every iteration. Presence.	off
logit, logger_name	Whether to log, and the log file.	on, ASSIM.log

screendata is not supported and says so.

[ensemble]

Key	Meaning	Default
ne	Ensemble size.	100 when a prior is generated
state	State variable name(s).	required (or controls)
prior_<name>	Prior of each state variable; see below.	required unless importstate
importstate	.npz with one (n, ne) array per state variable, used instead of generating a prior. importstaticvar is the older spelling.	none
seed	Seed for the run's private random stream: prior, perturbed observations, outlier and crash replacement, localization shuffles. Without it NumPy's global stream is used.	none
save_prior	Write the generated prior as prior_ensemble.npz. Flag.	on
sim_limit	Wall-time limit passed to the simulator.	none
disable_tqdm	Hide progress bars. Flag.	off
multilevel	Multilevel ES-MDA: levels, en_size (members per level), ml_weights or cov_wgt (weights per level, normalised).	none
savefolder	Folder for popt's save_prediction output.	Predictions

[ensemble.prior_<name>]

Key	Meaning
mean	A number, a list per cell, or a .npz holding the mean field.
var (or variance)	Variance per layer.
range (or corr_length), aniso, angle, vario	Correlation length, anisotropy, angle and variogram type (sph, exp, gau) of a field prior.
grid	[nx, ny, nz]; scalars are [1, 1, 1].
limits	[lower, upper] the realisations and every update are clipped to.

popt additions

Key	Meaning	Default
controls	{name: {initial or mean, var/variance or std ('5%' of the range needs limits), limits}}; values may be .npy, .npz or .csv files.	required
natural_gradient	Gaussian ensemble: scale the gradient by the covariance. Flag.	on
num_models	Realisations per control for robust optimisation.	1
save_prediction	Pickle each forecast under savefolder with this name.	none
marginal, theta	Generalized ensemble: marginal family (BetaMC, Beta, Logistic, TruncGaussian, Gaussian) and its parameters.	BetaMC

[optim]

Options every optimizer takes (popt.optimization_methods.OptimizerBase):

Key	Meaning	Default
maxiter	Number of update iterations.	100
ftol, xtol, gtol	Stop on relative objective change, on state-change norm, on projected-gradient infinity norm.	1e-5, 1e-8, 1e-5
transform	Optimise in the unit cube [0, 1]^n (needs bounds). Flag.	off
saveit, savefolder	Save the result after every iteration, and where.	off, Iteration_Results
restart, restartsave, restart_file	Checkpointing, as for the schemes.	off, off, <optimizer>_restart.pkl
logit, logger_name	Whether to log, and the log file.	on, OPTIM.log
fun0, jac0, hess0	Starting values to reuse instead of evaluating.	none
epf	Exterior penalty: r, r_factor, tol_factor, conv_crit, max_epf_iter. conv_crit is compared against the mean penalty with r divided out, so the objective must write penalty into the epf dict it is handed.	none

Per optimizer:

Optimizer	Keys
EnOpt	tol, alpha (or step_size), alpha_cov, beta, nesterov, alpha_maxiter, resample, cov_factor, hessian, normalize, optimizer (GD, Adam, AdaMax, Steihaug)
GenOpt	tol, alpha (or step_size), alpha_theta, alpha_corr, beta, nesterov, alpha_maxiter, resample, cov_factor, normalize, optimizer (GD, Adam). Takes args = (theta, corr), a jac_mut mutation gradient, and an optional corr_adapt (a CMA instance or any callable).
LineSearch	step_size, step_size_max, step_size_adapt, c1, c2, rho, lsmaxiter, lsmethod (0 backtracking, 1 Wolfe), normalize, recompute_jac, hess0_inv
TrustRegion	trust_radius, trust_radius_max, trust_radius_min, trust_radius_cuts, rho_tol, eta1, eta2, gam1, gam2, resample, convergence_criteria
SmcOpt	tol, alpha, alpha_maxiter, resample, cov_factor, inflation_factor, survival_factor, best_func

The constructors document each key.

[simulator] (or [fwdsim])

PET reads a few keys; the rest belong to the simulator wrapper.

Key	Meaning	Default
datatype	Data types the simulator reports, in order.	required
reporttype, reportpoint	Name and values of the report labels: a list, a .csv/.txt/.yaml file, or {start, end, freq} for a date range.	required by most wrappers
parallel	Members run at once in a local process pool; 1 runs them in sequence.	1
hpc	Run the members through the wrapper's HPC queue in batches of parallel. Flag.	off
compute_adjoints	The wrapper returns (prediction, adjoint) per member; the adjoints reach the analysis as an (nd, nx, ne) array. Flag.	off
saveforecast	Save each full forecast (sim_results.pkl) and the reconstructed compressed vintages (rec_results.pkl). Presence.	off

Legacy text files

.pipt/.popt files keep the ensemble's keys in the DATAASSIM block and lower-case every value, so data-type names written in upper case must match lower-case columns. pet convert my_case.pipt writes the same content as TOML, and pet migrate updates a file from daalg to scheme.