NEWS

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vbpm 0.9.1 (2026-09-05)

Test-portability release. No executable estimator or API behaviour changed, and no number a fit returns changed; 0.9.0 was rejected at CRAN's incoming checks and never reached the archive.

• The frozen r1.1 regression test compared vbfa() output to its stored reference with expect_identical(). That assertion is not portable: the estimator runs through compiled BLAS/LAPACK, whose SIMD and FMA choices differ between platforms, so a reference frozen under one BLAS reproduces only to within an ulp or two under another. CRAN's Debian pre-test disagreed in the sixteenth significant digit on four values and failed. The test now asserts agreement at a strict relative tolerance = 1e-8, which remains sensitive to material regression, and keeps the iteration count exact, since a different stopping point means the path itself changed. The frozen-reference output is no longer asserted bitwise; that property depends on the build.

• The pefa and bifactor vignettes replace their illustrative count rule with a declared analysis-side reader: dual ELBO/BIC count paths, three named minimum-congruence persistence profiles, and the companion study's L1/L2/L3 corroboration layering. On a real fitted path the deepest profile fails to resolve while the other two agree, so the sensitivity to declared depth is shown rather than asserted. Vignette prose and local code only.

• ?vbmimic no longer explains why pefa() refuses vbmimic fits in terms of factor-number selection, which pefa() has not performed since 0.9.0. The refusal itself is unchanged; only the stated reason was stale.

  This is the sole change to R/ since 0.9.0 and it is comment-only: one roxygen sentence rewritten, no executable line. src/ and data/ are byte-identical to 0.9.0, so every number a fit returns is unchanged and results produced under 0.9.0 reproduce exactly under 0.9.1 in the same computational environment.

vbpm 0.9.0

First public release. It was submitted to CRAN but not accepted, so it never reached the archive; see 0.9.1. pefa() is now a measurement-only factor-count sweep: it fits every K in a fixed consecutive window, reports candidate and between-candidate quantities, and chooses nothing. This completes an arc running through 0.8.0 (removed the stable verdict), 0.8.1 (removed absolute-fit gating), and 0.8.2 (removed automated raw/BIC selection). 0.8.3 was withdrawn and never reached CRAN.

Every structural number in a pefa() object changes, because the column-correspondence rule changed. Congruence, pooled and maximum RMSD, ARI, PIP RMSD, unmatched-column size, and the collision flag are not comparable across 0.8.x and 0.9.0, and neither is any threshold calibrated on them.

Breaking removals

The following existed in 0.8.3 and are gone. Removing them is intentional pre-1.0 breakage, not a deprecation cycle.

• select_K_elbow() is removed, together with pefa()'s cuts, sustain, stability_eps, $selected_K, and $boundary, and the boundary vocabulary and console advice that went with them. A count rule is now ordinary analysis code over the stored path, and it must say which variant it is:

  ## 20% cut on the ELBO path, full look-ahead, no boundary fallback.
  g <- x$transitions$ELBO_gain_pct
  ok <- vapply(seq_along(g), function(i) all(g[i:length(g)] < 20), logical(1))
  if (any(ok)) x$transitions$K_from[which(ok)[1]] else NA_integer_
  

  A capped-look-ahead variant and a variant with a boundary fallback give different answers on the same path; vbpm no longer supplies either, so the analysis names the one it used.

• Soft criteria and their counts (t_S, AIC_S, BIC_S) and the nominal count t_nom are no longer retained on $sweep. t is the effective hard parameter count at the resolved tau, rank-adjusted when rank_adjust = TRUE. An analysis that needs a soft criterion must refit; fit_stats() still returns all of them for a single fit.

• The per-candidate and per-pair status/reason taxonomy is removed. A fit error, malformed candidate, or nonfinite loading, PIP, ELBO, AIC, BIC, or t now aborts the whole call with an error naming the affected K, and no partial object is returned. RMSEA, SRMR, CFI, and TLI stay descriptive and may be NA without error.

• Eligibility machinery is removed: there is no salience screen, no stability_eps, no source/target eligibility count, no reduced-pair flag, and no target capacity policy. Every column participates in every comparison, so a comparison always holds exactly K_from scored pairs and no pair-count field is needed.

The correspondence rule

• Columns now correspond by minimum sign-aligned squared distance: with s = 1 when a'b >= 0 and -1 otherwise, each source column takes the target minimizing the squared length of a - s b. That is Equation 17 of Chen (2023) made invariant to whole-column reflection, and it is magnitude-sensitive on purpose. Absolute Tucker congruence is now only an exact-tie breaker and a reported shape diagnostic; a finite congruence outranks an undefined one, and the smaller target index settles anything still tied. No tolerance widens a near-tie into a tie.
• Backbone columns pair by position; each exploratory source then chooses independently. Reuse of a target is a collision, recorded as a logical fact and never repaired into a forced one-to-one assignment. A collision blanks no otherwise defined measurement.
• Comparisons are computed directly from their two endpoint matrices for every ordered pair, never chained through the candidates in between.
• Zero-norm columns participate: their aligned distance is defined and their congruence is not, so phi_min becomes NA_real_ rather than silently dropping the column.

The returned object

• A "pefa" object now has exactly sweep, transitions, persistence, loadings, pips, Q0, and settings, and its class is exactly "pefa".
• $sweep is K, ELBO, AIC, BIC, RMSEA, SRMR, CFI, TLI, t, iter, converged — one row per candidate.
• $transitions is one row per adjacent pair: K_from, K_to, ELBO_gain_pct, BIC_gain_pct, and the seven structural facts phi_min, rmsd, rmsd_max, ari, pip_rmsd, unmatched_ssl, collision. Raw gains are no longer duplicated here; the raw criteria are in $sweep. Each percentage divides by the largest positive gain on its own path, or is NA_real_ when that path has none.
• $persistence is now three upper-triangular matrices over the fitted K values, named exactly phi, rmsd, and collision, covering every ordered pair. phi holds phi_min and rmsd holds rmsd_max — not the pooled $transitions$rmsd. They are read directly as x$persistence$phi. No accessor function is provided: selecting a stored triangle would be a synonym for $, and a two-metric accessor would arbitrarily omit the collision mask.
• $settings holds only resolved fit-generating and fit-statistic controls: bifactor, general, v0, max_it, convChk, tolVal, tau, rank_adjust, rank_max_J. No analysis rule, no threshold, no verbose.
• There is no $provenance component and no hashing anywhere in the package. pefa() computes no schema, engine, data, Q0, settings, evidence, or lineage fingerprint, stores no build identity, and makes no cross-version object-reuse promise. The package version and session used for an analysis belong in that analysis's own run record. The digest dependency is dropped.
• There is no checkpoint, resume, optional save, interrupt handler, or partial-sweep return path, and no window-extension API. A wider window means rerunning pefa() over the whole wider window.

Convergence and warnings

• A well-formed candidate that stopped at max_it is retained with converged = FALSE and keeps every matrix and every comparison it takes part in. pefa() issues at most one aggregate warning per call, naming all affected K values. Convergence never blanks a defined number and never removes a candidate from the path.

Exports and methods

• The PEFA surface is exactly pefa(), ssl(), and the print(), summary(), and plot() methods.
• ssl() is colSums(Lam^2) per candidate, returned as a character-K-keyed list of double vectors, with the general column first in bifactor mode. It screens nothing and enters no correspondence rule. It is the companion to phi_min, which is a weakest-link statistic over every column: a near-empty column matches the smallest-norm target, contributes an arbitrary congruence, and often raises collision, and ssl() is what tells that case apart from structure actually moving.
• summary() returns exactly window, sweep, transitions, persistence, ssl, settings, and nonconverged_K. Its print method shows phi before rmsd and suffixes a persistence value with * where the parallel collision cell is TRUE; that is display formatting only and never touches the stored matrices.
• plot() keeps the descriptive objective, gain, and fit views. Soft criteria, threshold lines, and selection markers are gone, and a one-candidate gain view is an empty panel rather than an error.

Other

• pefa() imposes no upper bound on K relative to J. The Ledermann bound orients the choice of Kmax but is derived for an unrestricted model and does not constrain a regularized partially confirmatory candidate. Past it, expect nonconvergence and NA fit indices — RMSEA and TLI are undefined at non-positive degrees of freedom — and read both as evidence about the window.
• v0, convChk, and tolVal are explicit pefa() arguments and ... is gone: every control that changes a returned number is recorded in $settings.
• Fully exploratory sweeps (K0 = 0) are supported.
• AO (anchor-only) and AZ (anchor-zero) are the vocabulary used throughout the current documentation and vignettes. Earlier terminology survives only in the historical entries below, which are unchanged.
• vignette("pefa") now walks one sweep table by table on a deliberate overextraction example; vignette("bifactor") covers bifactor structures, AO versus AZ backbones, a Step-2 comparison derived from the Step-1 result, and an ordinary-versus-bifactor sweep illustration.

vbpm 0.8.3

This release makes the compact PEFA object easier to inspect and removes two uninformative PIP summaries. It is a breaking refinement of the 0.8.2 schema; the 0.8.2 release history below is unchanged.

• $sweep is now an ordinary scalar-only data frame. Candidate loading and PIP matrices move to top-level, K-named $loadings and $pips lists, so a candidate is read directly as x$loadings[["4"]] or x$pips[["4"]]. Their names always equal as.character(x$sweep$K); full candidate fits are still not retained.
• pip_sum and pip_product are removed from $transitions. Both thresholded PIPs at .5 and were diluted by fixed design cells; the product also returned zero whenever all changes ran in one direction. The replacement pip_rmsd is continuous: after loading-column matching, it is the RMSD between PIPs over matched cells that are selectable at both endpoints. Fixed backbone cells and unmatched columns are excluded. Loading-based metrics remain available when only a PIP endpoint is malformed.
• Loading alignment now follows Equation 17 directly: each retained non-backbone column in the smaller fit independently selects its nearest retained column in the larger fit. Reuse is allowed and the logical $transitions$collision flag reports when a larger-fit column is selected more than once; it is not silently resolved by a one-to-one assignment.
• Bifactor transitions no longer suppress all stability fields. The labelled general column is removed and the same alignment, screening, loading, PIP, collision, and unmatched-column definitions are applied to the group block, making same-data oblique and bifactor sweeps directly comparable. The full K + 1 matrices remain available for candidate-level inspection. This supersedes the earlier blanket implementation warning: relative sweep reliability is now assessed empirically rather than decided from model class.
• The remaining unmatched_max stays a separate continuous, descriptive size diagnostic. It is not a loading-salience cutoff or an automatic selection rule.
• The bifactor vignette now runs ordinary-oblique and bifactor LPC sweeps on the same heterogeneous bifactor population and K = 2:5 window. In this reproducible example the ordinary sweep selects the true three groups at both cuts, whereas the bifactor sweep selects its lower boundary. A derived SS-loading table (colSums(Lam^2)) exposes weak columns without adding a result field or selection rule; replicated R6 work will test whether this example generalizes.
• summary() derives a per-candidate ssl component -- the sums of squared loadings colSums(Lam^2) -- from $loadings at summary time, and its print method displays one row per candidate. In bifactor mode the values cover all K + 1 columns with the general factor first, unlike the group-block transition diagnostics. SS loadings are descriptive column sizes, not Gram eigenvalues, and enter no selection rule; the sweep object itself stores no derived state.
• The top-level object is reduced to $sweep, $transitions, $loadings, $pips, $selected_K, $boundary, $Q0, and $settings. The lean $settings list contains only cuts, sustain, bifactor, general, tau, stability_eps, and rank_adjust. The requested window is derived from $sweep$K, and the backbone size from ncol(x$Q0).

vbpm 0.8.2

This release deliberately simplifies PEFA before 1.0 and changes both its object schema and its adjacent-solution diagnostics.

• fit_stats.vbfa() now uses the deterministic nominal hard-selected parameter count by default (rank_adjust = FALSE). The numerical Jacobian-rank count remains available only by explicit request and requires the suggested package numDeriv; rank_max_J is an explicit computational guard. pefa() exposes and records the same controls, computing the chosen statistics while each candidate fit still exists.
• A pefa result now has exactly two data frames. $sweep retains scalar candidate statistics and adds loading and pip matrix list-columns; $transitions retains adjacent ELBO/BIC gains and the revised diagnostics. Named $selected_K and parallel $boundary vectors report the ELBO-gain result for every named cut. Raw ELBO/BIC and BIC-gain selections are no longer returned automatically, but remain directly reproducible from the retained scalar paths.
• Full candidate fits, $selection, and selected_fit() are removed. Extract loading/PIP matrices by matching a desired K to $sweep$K; explicitly refit that design when downstream work needs a complete vbfa object.
• Adjacent oblique candidates are compared with a deterministic, backbone-aware loading/PIP matcher. It holds the Q0 columns fixed by position, screens free columns by squared L2 norm, and matches the retained free columns by minimum SSE. The transition fields are now rmsd, rmsd_max, signed phi_min, ari, pip_sum, pip_product, and the separate size diagnostic max_unmatched_loading; the previous phi_mean and ambiguous max_loading fields are removed.
• All transition diagnostics remain descriptive and do not enter automatic selection. Signed congruence can be unstable for near-zero-mean contrast columns; PIP summaries can be diluted by fixed design cells; and max_unmatched_loading is not a .3 salient-loading rule. Bifactor edges, failed endpoints, and inapplicable or incomplete comparisons return typed NA diagnostics.
• General sweep mechanics and stability interpretation now live in the PEFA vignette. The bifactor vignette stays focused on the compact two-step first-order-count and matched-model comparison.
• Version 0.8.2 still has no persistence, checkpoint, resume, extension, or interrupt subsystem. Its internal sweep seam is groundwork only: this release does not export extend.pefa(), vblvm(), MIMIC sweeping, ESEM support, or a generic sweep engine.

vbpm 0.8.1

pefa() is reduced to a compact, in-memory factor-number sweep. This is a breaking cleanup of the 0.8.0 interface; the 0.8.0 release history below is left unchanged.

• The paper-defined workflow now fits only ordinary oblique candidates with diagonal residuals. The research-extension bifactor = TRUE mode remains, with K consistently denoting the number of group factors. Standalone orthogonal and local-dependence models remain available through vbfa() but are no longer PEFA sweep modes.
• ELBO and BIC each receive raw and gain selections. AIC remains in $sweep as a descriptive fit statistic but is not automated as a gain rule. select_K_elbow() and pefa() now use the same full sustained-drop scan: a stop requires all sustain following gains, including near the right edge.
• RMSEA, SRMR, CFI, and TLI are descriptive trajectories, not eligibility gates. A selection requires one complete, converged, finite criterion path; failed paths are not bridged or split into later components.
• The result has three compact tables: candidate-level $sweep, edge-level $transitions, and rule-level $selection. Raw adjacent ELBO and BIC gains are stored with their transitions, while each rule records its own gain normalizer and threshold.
• Every candidate fit is retained in $fits, and selected_fit() retrieves the primary selected fit. Removed are keep_fits, duplicate selected-fit fields, compatibility aliases and schema fields, the secondary vbpm_sweep class, and transition_detail().
• Removed without deprecated aliases are the 0.8.0 delta, fit_cut, cutoffs, orthogonal, and keep_fits arguments. Named cuts remains the only multi-rule interface; PEFA rejects local-dependence and orthogonal mode controls passed through ....
• Adjacent-count stability is deliberately small and descriptive. Consecutive oblique solutions are aligned by a simple best-unused-column convention and report phi_min, phi_mean, ari, rmsd, and the unmatched column's max_loading. There is no assignment search, tie policy, fixed stability cutoff, status vocabulary, or public matching detail.
• pefa() has no persistence, checkpoint, resume, interrupt, or overlap-reuse subsystem. A boundary selection asks for a complete rerun with a better bracketed window.
• PEFA fit statistics now use the nominal hard-selected parameter count consistently. Hard-selected CFI returns one when its comparison denominator is zero, matching the paper's stated convention. This changes reported numbers, not just interfaces: on identical data, $sweep AIC/BIC (and potentially a BIC selection) can differ from a 0.8.0 run that silently used the optional Jacobian rank adjustment, and the new column alignment changes every stability column relative to 0.8.0's matcher.
• The PEFA vignette now follows the paper's compact workflow and labels adjacent-count stability as a package extension. The bifactor vignette is reduced to definitions, direct anchored fitting, special_effects(), and a two-step first-order-count then matched BIC comparison.

vbpm 0.8.0

pefa() is reorganized around what each quantity is indexed by, and gains adjacent-count stability diagnostics. This release changes results as well as structure -- see the two breaking notes below.

• Three tables instead of one. Everything a sweep produces is indexed by a candidate, a transition between adjacent candidates, or a selection rule:
  • $sweep keeps one row per candidate (ELBO, Objective, AIC, BIC, fit indices, convergence, timing) and loses all six gain columns;
  • $transitions is new -- one row per adjacent pair, holding the gains (which are properties of a step, not of a candidate) together with the stability indexes below;
  • $selection becomes a long-form table with one row per criterion x form x cut x eligibility scope, recording the normalizer gain_max, the absolute threshold, selected_K, and both boundary readouts. No percentage-of-largest-gain column is stored anywhere: the normalizer depends on the eligibility scope, so percentages are computed for display.
• Adjacent-count stability. Each transition reports how much of the K-factor solution survives inside the K+1-factor solution the sweep already fitted: phi_min (the binding index), phi_mean, n_phi90, ari, rmsd, surplus_max, per-endpoint assignment-coverage counts, and stability_status. Columns are matched by bottleneck (max-min) Tucker congruence, which -- unlike the greedy stored-order matching used in hand-rolled versions -- is permutation invariant and actually maximizes the binding statistic. transition_detail() returns the per-column material behind one row.
• The package computes, it does not render verdicts. No stable column, no comparison against any threshold. The manuscript's .85 operating point is documented as provisional and specific to its own workflow.
• Stability is gated where loadings are not interpretable. Under orthogonal/bifactor sweeps the padded columns are rotationally indeterminate, and a non-converged endpoint is not a solution; in both cases the loading-based columns are NA with the reason in stability_status. Gains remain valid in every mode.
• New cuts argument replaces the overloaded scalar delta: a named vector of gain thresholds with exactly one primary entry, so a primary rule and any number of sensitivity rules are evaluated in one call. The default stays c(primary = 10); delta continues to work as a deprecated alias, and supplying both is an error.
• New keep_fits ("all", "selected", "none") for callers who want the tables without the fit payload. selected_fit is always returned. summary.pefa() now carries the three tables and no fit payload.
• Breaking, structural: code reading ELBO_gain, BIC_gain, or any *_gain_pct column from $sweep must read $transitions instead; summary()$comparison is now summary()$sweep; $selection is a data frame rather than a named vector. $boundary and $delta survive as deprecated aliases of $window_boundary and $cuts[["primary"]].
• Breaking, in results: selection no longer bridges a gap. When an interior candidate is ineligible (non-converged, or failing the absolute-fit gate), the old code differenced across it and reported a two-factor jump as a one-factor marginal gain. Now an unusable edge is skipped and resets the sustained-run counter, so selected_K can differ from 0.7.1 on any sweep with an interior gap. Sweeps without a gap are unaffected.
• Removed: the save_path checkpoint/resume subsystem. pefa() performs one in-memory sweep and returns one complete object; it writes nothing and cannot resume an interrupted call. Saving a result is ordinary saveRDS() workflow. The manifest that made resuming trustworthy is gone with it and is not replaced, because a single in-memory sweep cannot pool candidates fit under different settings in the first place.
• Fixed: print.pefa() inferred the fitting mode from $fits[[1]], so its orthogonal weak-identification caution silently vanished whenever the first candidate's fit was absent. Both print methods now read explicit top-level mode settings. Reported also in ?pefa.
• pefa vignette: the checkpoint walkthrough is replaced by a section on saving a sweep and widening its window, which shows that re-running a wider window reproduces the shared candidates bit-for-bit rather than wasting them, and that Kmin cannot go below K0.
• bifactor vignette, Section 6: three corrections to the two-step process. Cut disagreement is no longer described as the workflow's protection against absorbed local dependence -- it is not a dependence detector, and the hard case leaves every count-level indicator clean; residual inspection is now an unconditional step, labelled as the exploratory sensitivity it is. The doublet repair no longer adds a two-item factor, which perturbs the two competitors differently (the oblique arm estimates the new column's correlations while bifactor = TRUE forces it orthogonal); it now frees the same residual edge in both arms with ld = TRUE and a shared Qe, which reverses the contaminated verdict at both anchoring depths. The thin -9 LPC margin is read against the vignette's own small-margin warning, and the accompanying manuscript is now cited by name rather than as "the accompanying manuscript."

vbpm 0.7.1

• Documentation currency pass. The README's "Known limitations" header was still dated 0.5.0, and the list was missing two limitations established since: bifactor factor-number sweeps are weakly identified (an omitted group factor is absorbed by the unspecified entries of the remaining columns, so the selection is uninformative -- with a pointer to the two-step route that does work), and vbmimic() has no direct covariate-to-item paths, so it models impact but cannot express or detect differential item functioning. A quick-start comment that named the $design/$settings fields removed in 0.7.0 was reworded.
• Dropped three unused namespace imports (stats::rnorm, stats::var, stats::quantile).

vbpm 0.7.0

Slimming release: fitted objects now store each quantity exactly once. No estimator changes -- every number a model produces is unchanged.

• Removed the mirror lists $coefficients, $design, $posterior, and $settings from vbfa() and vbmimic() fits. Each of their elements duplicated a top-level component (Lam, Phi, pi, Lam_var, eta_cov, Q, Qe, orthogonal, ld, bifactor, v0); they had no consumers anywhere in the package, its tests, or its vignettes, and coef() never read them. vbmimic()'s standardize setting, the only element that lived solely in a mirror, is now a top-level component.
• preprocess$missing_mask is stored only when the data actually contain missing values (NULL otherwise). For complete data it was an all-FALSE N x J matrix and the single largest part of a fit -- 65% of the object at N = 3000, J = 27. preprocess$n_missing still reports the count in all cases.
• pefa() no longer returns the $fit alias, which was a third copy of the selected model (already available as $selected_fit and inside $fits) with no consumers.
• Net effect: a saved vbfa fit is about half its previous size (144 KB -> 74 KB for N = 3000, J = 27), and a saved sweep about 20% smaller. A new test pins these invariants so the duplication cannot silently return.
• Internal: the QUIC wrapper no longer copies the solver's output array into an identical new array.
• README: proper C++ toolchain instructions. Because the package ships compiled code, installing it requires a toolchain -- the one real setup barrier. The installation section now opens with a one-line check (pkgbuild::has_build_tools(debug = TRUE), a genuine compile test on every platform) and, if it fails, per-platform instructions and links: Rtools matched to the R version on Windows, xcode-select --install on macOS, and the distribution's R development packages on Linux.

Nothing was on CRAN when these fields were removed, so no released API is affected; scripts that read the documented top-level components (fit$Lam, fit$pi, fit$Q, ...) are unaffected.

vbpm 0.6.1

• New special_effects() post-processes an orthogonal bifactor fit into the three summaries of the bifactor vignette in one call: the Schmid-Leiman proportionality check (per-group and item-weighted mean CV of the group/general loading ratio), the approximate higher-order parameterization (gamma per group factor, lambda per item), and the testlet/special effect sizes of Zhang & Chen (2024, Eq. 16) with posterior-inclusion gating of unspecified loadings. Group membership is inferred from anchors and inclusion probabilities; unassigned, cross-loaded, and no-general-loading items are flagged rather than silently pooled. Deliberately descriptive: no cutoff argument and no verdict -- the conventional .1 reading of the mean CV is mentioned as suggestive, and all quantities are reported regardless. Accepts bifactor = TRUE fits natively and legacy hand-built designs (one all-specified column under orthogonal = TRUE). Tests pin the function to an independent reimplementation of the vignette's plain-R code.

vbpm 0.6.0

• New bifactor mode in vbfa() and pefa(). Previously a bifactor was expressed by hand-building a general column into Q under orthogonal = TRUE, which made the user-facing factor count include the general factor -- off by one against the comparable oblique model, a recurring source of confusion in sweeps ("Kmin = 3 means 2 group factors"). With bifactor = TRUE, Q (and pefa()'s Q0) supply only the group design; the general column is added internally, and K everywhere means group factors, directly comparable to an oblique K-factor model. Details:
  • bifactor = TRUE implies orthogonal factors and overrides orthogonal = FALSE (with a message when the latter was passed explicitly).
  • A new general argument designs the general column (1/0/-1 per item, default all 1), so bifactor-(S-1)-style designs (some items with no general loading) and partially exploratory general columns are now expressible.
  • Passing a Q that already contains an all-specified column together with bifactor = TRUE is an error rather than a silent double count.
  • Fits carry bifactor, n_general, and general; print() shows "1 general + K group factors". The pefa sweep table gains a K_total column and the print methods label the window as group factors.
  • The long form (cbind(1L, Q) with orthogonal = TRUE) still works and is bit-identical -- the new mode is bookkeeping, not a new estimator -- and a regression test enforces that equality.
  • The relabeling changes none of the identification facts: bifactor sweeps remain weakly identified and the ?pefa warnings keep full force.
  • Non-bifactor orthogonal = TRUE fits now print as "orthogonal" rather than "orthogonal/bifactor".

vbpm 0.5.0

Documentation-and-parallelism release preparing the CRAN submission, plus one estimator bug fix.

• Removed: vb_fit(). The pre-0.4.0 name for fit_stats() survived 0.4.x as a thin wrapper; it is gone as of this release (before any CRAN submission, so no released API is broken). Use fit_stats().
• sim_fa() gains gamma for direct higher-order (testlet) generation: a scalar or per-factor vector of second-order loadings in (0, 1) makes each group factor load on one general factor, and the data are generated from the equivalent Schmid-Leiman orthogonal bifactor matrix (returned as MLA, with the first-order matrix and gamma as MLA1/gamma). This replaces the hand-built-matrix recipe previously shown in the bifactor vignette.
• plot.pefa() redesigned. The objective panel gives the objective and BIC their own axes (one shared axis flattened both curves into unreadable lines); the fit panel splits absolute misfit (RMSEA/SRMR) and incremental fit (CFI/TLI) into side-by-side panels with conventional cutoffs; all panels use real plotting symbols that match their legends (previously matplot() drew digit characters while the legends showed symbols) and mark the selected K with a dotted vertical line.
• print.summary.pefa() now prints one compact comparison table with the raw objective and BIC, their marginal gains as % of the largest gain (the quantity the selection rule actually thresholds), the fit indices, and a marker on the selected row. Raw gains and timing remain in $comparison.
• Orthogonal (bifactor) sweeps are now flagged as weakly identified. Simulations from true bifactor and true higher-order populations show the ordinary bifactor sweep (general column + anchored groups, rest -1) systematically selects the lower window boundary regardless of the true K: an omitted group factor's rank-one covariance block is absorbed by the unspecified entries of the remaining columns, making the candidates covariance-equivalent -- and the truth-sized candidate inside such a sweep is itself not interpretable. ?pefa gains a dedicated section; the print() methods replace the generic "extend the window" advice with an explicit caution when an orthogonal sweep lands on the lower boundary.
• The bifactor vignette is rebuilt as a small tutorial paper. It opens with the covariance geometry that drives everything (cross-cluster blocks are rank-one under both bifactor and oblique models, so a general factor is identified only by within-cluster rank-two structure), demonstrates the sweep failure on both true-bifactor and higher-order data, and closes with a validated two-step decision route: (1) an ordinary oblique pefa() sweep for the first-order factor count -- interior selections are trustworthy there even when the data are bifactor or higher-order; (2) anchored oblique-K versus anchored bifactor-(K+1), compared by BIC (not ELBO, whose prior mass differs across the two designs); (3) within the winner, the Schmid-Leiman mean-CV check (bifactor side) or a triad factorization of the fitted factor correlations (oblique side) settles bifactor versus higher-order versus plain correlated factors. Every population in the vignette routes correctly, and the route's power limits (a near-homogeneous true bifactor needs a large sample at step 2) are reported from a 3 x 3 x 3 simulation grid. ?pefa summarizes the route.
• Fixed: inflated residual variances for anchored items under local dependence. The posterior variance of fixed-zero (Q == 0) loadings was left at its initialization value 1 instead of 0, and the LD branch's expected residual covariance summed loading variances over all columns -- adding roughly +1 per fixed-zero column to the residual variance of every item that had any. On the standard test design, anchored items' residual variances came out ~5x too large (loadings and residual-edge selection were unaffected). Diagonal (ld = FALSE) results are unchanged -- the r1.1 bit-exactness fixture still passes -- and the reported Lam_var is now 0 for fixed-zero entries in both modes. The defect is inherited from the reference implementation ld-vb_r.R, which computes the same term the same way.
• sim_fa() gains mla: supplying a population loading matrix switches it to matrix-driven generation (pattern arguments are then ignored), with the same convention as sim_lvm(). Its factor-1-2 correlation argument is renamed ph1 -> ph12 to match sim_lvm(), so ph1 now exists only in sim_lvm(), where it is the correlation among latent predictors. Both help pages gained matrix-driven examples and now read as a matched pair.
• New vignette bifactor: orthogonal bifactor estimation on true bifactor data, a pefa() sweep over bifactor candidates -- including an explicit note that Kmin/Kmax count the general factor, and a demonstration of why factor-number discovery is intrinsically hard for orthogonal bifactor structure (an omitted group factor is absorbed by the unspecified entries of the remaining columns) -- and the higher-order/testlet connection: simulating a higher-order CFA directly via sim_fa(gamma = ), checking the Schmid-Leiman constraint with a mean-CV rule (approximately higher-order when mean CV < .1), transforming back to higher-order parameters via the per-cluster mean ratio, and computing special-effect sizes by Eq. 16 of Zhang & Chen (2024) with posterior-inclusion-based selection of unspecified loadings. The testlet and higher-order models are noted as mathematically equivalent.
• vbfa vignette reorganized: restricted-Qe local dependence (testlet-block design matrices), a diagonal-vs-LD model comparison via fit_stats(), executed v0-path comparisons, an ld_control demonstration, and a "Missing data" section stating the missing-at-random assumption (Chen, 2021) with simulated and empirical demonstrations. The factor-number and bifactor material moved to the pefa and bifactor vignettes.
• pefa vignette expanded: the lead sweep now runs vbfa()'s default warm-started v0 path on a true K = 4 simulation (N = 500, window 2:6 on a K0 = 2 backbone) and recovers it in the interior; checkpoint/resume with the provenance manifest (including the refusal on changed settings), executed plot() panels, a boundary demonstration on the same data, and a sweep on data with minor factors showing the gain rule ignoring dust dimensions.
• vbmimic vignette: missing responses in Y demonstrated.
• Housekeeping: stale tmp/ artifacts and the sibling vbpm.Rcheck/ removed; references across README and vignettes made consistent, adding Chen (2021, Multivariate Behavioral Research) and Zhang & Chen (2024, Applied Psychological Measurement).

vbpm 0.4.0

• vbmimic() now also accepts missing responses in Y. Its residual covariance is diagonal, so the joint Gaussian conditional collapses to the factor-model mean eta_i A', with the conditional variance 1 / V_j carried into the residual sum of squares; the covariate information is already carried by eta_i. Missing values in X remain an error: covariates are conditioned on rather than modelled, so imputing them would require a distributional assumption the MIMIC model does not make.
• vbfa() now handles incomplete continuous-response data by deterministic, joint Gaussian conditional-moment updates. The model and conditional moments match the data-augmentation formulation used by LAWBL and the related PCFA MCMC work; rows or items with no observed responses are rejected.
• Local-dependence fits now expose the terminal VECM objective derived in the LD-PCFA-VB V4 manuscript. It is stored as objective with objective_type = "vecm"; ELBO remains NA because the residual precision and mixing probability are point updates rather than variational factors.
• New fit_stats() S3 generic works for all vbpm_fit objects. It computes covariance fit statistics for diagonal and LD vbfa fits and returns a clearly marked limited result for vbmimic; vb_fit() remains as a compatibility wrapper.
• pefa() now returns a c("pefa", "vbpm_sweep") object with candidate fits, a sweep table, summary(), plot(), and selected_fit(). Summaries report objective, objective-gain, ELBO, ELBO-gain, BIC, and BIC-gain selections.
• The package now has focused vbfa, vbmimic, and pefa vignettes.
• Verification for the above: the Gaussian conditional-moment kernel is now an internal function (.cond_moments()) tested directly against textbook multivariate-normal conditional means and covariances, for diagonal and full residual covariance; missing-data fits are checked for mask integrity and row-permutation invariance; LD fit statistics are checked to be built from the residual covariance W rather than the precision; and missing data is checked to compose with local dependence.

vbpm 0.3.0

Fits are now classed objects, output names are plain-language, the default is quiet, and the package has vignettes. One release, one breaking-change window, before any public release — no public API ever carried the old behaviour.

• S3 class vbpm_fit. vbfa() returns c("vbfa", "vbpm_fit") and vbmimic() returns c("vbmimic", "vbpm_fit"). A fit is still a plain named list — fit$Lam etc. are unchanged and remain public API — but print(fit) now shows a compact summary instead of dumping every matrix, and coef() works. See ?vbpm_fit for exactly what the class does and does not change.
• Fits carry their own settings and designs. Q (and Qe, Q_A, Q_B), orthogonal, and ld are stored in the fit, which is how vb_fit() and print() know what they are looking at without being told.
• Output renames (the variational .q. notation stays inside the estimators, where it mirrors the papers' derivations; the returned names are now plain language):
  • sigsq.q.Lam -> Lam_var, PHI.q.eta -> eta_cov, M.q.PHIiver -> Phi_inv_mean (in vbfa());
  • sigsq.q.A/sigsq.q.B -> A_var/B_var (in vbmimic());
  • plotDat dropped (always-NULL placeholder).
• Quiet by default. vbfa(convChk = FALSE) is now the default, and progress goes through message() (suppressible) instead of cat(). vbmimic() already behaved this way.
• Vignettes: "Getting started with vbpm" (Q design, fitting, fit statistics, factor-number selection, bifactor, local dependence, the NLSY empirical example, and turning graded prior knowledge into a Q matrix) and "MIMIC models with vbmimic".
• Stored-reference regression test: vbfa(v0 = 0.001) is now proven bit-identical to the frozen fixed-spike estimator behind the 2025 SEM paper (fixture generated from the original source; 79 iterations, all deltas exactly zero). This is the guarantee that lets analysis code migrate from the historical scripts to the package.

vbpm 0.2.0

• vbmimic() — regularized variational Bayes for extended multiple-indicators multiple-causes (MIMIC) models, with spike-and-slab priors on both the measurement (Q_A) and the structural (Q_B) part. Supports a warm-started v0 path. The defaults (v0 = 0.001, standardize = FALSE) reproduce the estimator of Jin & Chen (2025, Multivariate Behavioral Research) bit-for-bit. The ELBO is not yet available, so vb_fit() and pefa() do not accept vbmimic fits.
• vbfa() gains an explicit ld switch for local-dependence estimation. ld = FALSE (default) fits diagonal residuals and ignores Qe (with a warning if one is supplied); ld = TRUE with Qe = NULL means fully exploratory local dependence (Qe = matrix(-1, J, J)); an explicit Qe is validated as before. Previously the mode was toggled implicitly by whether Qe was supplied.
• Fixed: vb_fit() defaulted orthogonal = FALSE regardless of how the model was fit, so calling it on a bifactor (orthogonal = TRUE) fit without repeating the argument silently counted K(K-1)/2 nonexistent factor correlations, biasing t, AIC, BIC, RMSEA, CFI, and TLI. vbfa() now records orthogonal (and ld) in the fit object and vb_fit() reads it from there; a contradictory explicit value is an error.
• nlsy27 — the NLSY 1997 empirical illustration dataset (3,458 x 27, mixed-type), carried over from LAWBL.
• Examples added or extended for vbfa() (bifactor, local dependence, empirical data), vb_fit(), pefa(), and select_K_elbow().
• sim_lvm() — latent-variable-model data generator, absorbed from the LAWBL package, which vbpm supersedes. Simulates observed predictors (P, b) and latent predictors (K1, ph1, b1) in addition to the factor-analytic features. It complements sim_fa(): sim_lvm() is driven by a loading matrix and covers predictor designs and mixed response formats, while sim_fa() is driven by the loading pattern (items per factor, alternating cross-loadings, minor factors).
  • New phd argument: correlated structural disturbances, so designs with an unrestricted factor residual covariance can be simulated.
  • New phx argument: the covariate correlation, previously tied to phi.
  • Fixed: with covariates present, the missingness mask was recycled across the covariate block, so NAs appeared in X. Missingness is now confined to the J items.
  • Added validation for the predictor coefficient matrices and for designs that imply a non-positive disturbance variance.

vbpm 0.1.0

First release.

• vbfa() — regularized variational Bayes factor analysis across the confirmatory–exploratory continuum. Spike-and-slab priors on unspecified loadings; optional warm-started dynamic regularization path (v0 a vector); orthogonal bifactor parameterization (orthogonal = TRUE); optional sparse residual / local-dependence estimation (Qe) via a graphical spike-and-slab prior solved by QUIC. A scalar v0 = 0.001 reproduces the fixed-spike estimator exactly.
• vb_fit() — SEM-like fit statistics (RMSEA, SRMR, CFI, TLI, AIC, BIC, ELBO) with hard selection as the default.
• pefa() and select_K_elbow() — window sweep over the number of factors with a scale-free gain rule for factor-number selection.
• sim_fa() — simulate factor-analytic and IRT data with cross-loadings, local dependence, minor factors, categorical responses, and missingness.

Not implemented in this first release

All three items below were addressed in 0.4.0; they are recorded here as the state of 0.1.0. See "Known limitations" in README.md for current status.

• Missing-data support in vbfa() (errored on NA). Added in 0.4.0 for continuous responses, by in-loop Gaussian conditional moments.
• ELBO under the local-dependence model (NA). Resolved in 0.4.0 by supplying the quantities that are actually defined — the terminal VECM objective and the conditional bound ELBO_conditional. ELBO remains NA by design, because the precision and mixing proportion are point updates rather than variational factors, so no single joint mean-field bound exists to report.
• LD-aware vb_fit(). Added in 0.4.0 via fit_stats(), which builds the implied covariance from the residual covariance W and counts selected residual edges.