Changelog

Upcoming: 1.1.0

The dev branch is at version 1.1.0. The entries below are merged into dev but not yet released.

Features:

• Energy ensemble support across the codebase: PlaneWave, Probe, SMatrix, BlochWaves and CTF accept a list of energies, and the resulting EnergyAxis propagates through indexing, angular sampling, unit conversion and diffraction-spot indexing (PR #257)

• C-PRISM: SMatrix(upsample=True) reduces every probe from the complete plane-wave expansion of the aperture, so the interpolation factor only sets the number of multislice runs. Adds CompressedSMatrixArray and GridScan.commensurate (PR #318)

• Phonon-loss (thermal diffuse scattering) energy-loss workflow: EnergyResolvedAtomsEnsemble, phonon_loss_diffraction_patterns, momentum_resolved_spectrum and MomentumResolvedSpectrum, the SpectralAnnularDetector and SpectralSlitDetector, and detailed-balance thermal weighting that splits the classical TDS signal into loss and gain sides (PR #324, PR #351)

• Linear-scaling PRISM-EELS for core-loss simulations: SMatrix.transition_potential_scan, with single- and double-channel scattering and an optional windowed inelastic crop (PR #289)

• In addition to the Gaussian (G) distribution, now also implemented Lorentzian (L), Voigtian (convolution L * G) and pseudo-Voigtian (L + G) source-size distributions and filters (PR #270)

• The exact free-space propagator is now the default for Fourier multislice, FourierMultislice(order="exact"), replacing the paraxial approximation. Spatial frequencies beyond k > 1 / lambda are treated as evanescent rather than propagating; the paraxial propagator remains available as order=1 (PR #298)

• Magnetic potentials and fields from collinear GPAW calculations: gpaw_magnetic_fields builds the electrostatic potential, vector potential and magnetic field from the same calculator(s) in one call, returning a GPAWMagneticFields bundle with .tile(), .combined_potential() and .show(); rotate_field now defaults to "auto" (PR #326)

• GPAWParametrization is now usable: it fits a Lobato-form IAM potential to the X-ray scattering factor of an all-electron GPAW calculation, with working ionization support and a regularized fit (PR #329)

• Potential(sampling="auto", slice_thickness="auto") automatically finds a grid commensurate with the atomic lattice — so translation-equivalent atoms discretize identically — near the usual default targets (\(0.05 \ \mathrm{Å}\), \(1 \ \mathrm{Å}\)), preferring FFT-fast grid sizes wherever that is compatible with commensurability. New grid.round-to-fast-fft config key ('auto'/True/False), Grid.round_to_fast_fft(), and is_fast_fft_size/next_fast_fft_size helpers in abtem.core.fft (PR #274, PR #347)

• Significant improvements on simulating large potentials on GPU, alongside minor performance improvements (PR #269)

  • The potential is now built in chunks of contiguous slices instead of all at once, keeping peak VRAM bounded; new config key potential.slice-chunk-size (default "auto")

  • Opt-in multi-GPU via the new config key dask.multi-gpu (requires dask-cuda)

  • cupy.fft-cache-size’s previous 0 MB default silently disabled the cuFFT plan cache; changed to -1 (unlimited) here, then to the device-relative auto default below once unbounded retention turned out to cost tens of GB on FFT-unfriendly grids

Performance:

• The projection integrator is shared by reference across ensemble members instead of being deep-copied (and re-uploaded to the GPU) for each (PR #350)

• Removed a redundant potential rebuild on every scan chunk (PR #340)

Dependencies:

• The core-loss extra is merged into a single gpaw = ["hankel", "sympy"] extra, and a new all extra installs every optional runtime dependency (PR #329)

Bugfixes:

• GPAWPotential for the new-style GPAW calculator API (GPAW 26+), and GPAWPotential.from_file on old-style restarted calculators (PR #325)

• GPAWPotential single-calculator frozen_phonons ensemble building (PR #327), plus removal of dead and broken code from GPAWPotential and GPAWParametrization (PR #328)

• FieldArray.tile() for vector-valued fields, and unsupported frozen_phonons/repetitions on magnetic fields now raise instead of being silently ignored (PR #326)

• Silent corruption in eager multislice for potentials with two or more ensemble axes (PR #333)

• numba TypingError in quasi-dipole interpolation on some numba/numpy pairings (PR #332)

• Single-point GridScan failing when built lazily (PR #342)

• LinearAxis losing its offset under dask ensemble chunk partitioning (PR #344)

• Nondeterministic atom loss in orthogonalize_cell, and a hardened Gram-Schmidt fallback (PR #345)

• Repeated axis labels and colorbar overlap in exploded spectrum panels, and silently returned zeros for single-configuration TDS (PR #351)

• Azimuthal convention in prism_coefficients, which reflected azimuthally dependent aberrations in a PRISM reduction with a CTF, and exit planes not being remapped when slicing a PotentialArray (PR #318)

• numpy 2.5 test failures caused by an ASE deprecation warning (PR #343)

• Probe.transition_potential_scan raised for a scan split into more than one chunk (for example through max_batch) unless the scattering sites were passed explicitly (PR #353)

• Colorbars did not span multi-row exploded plots, and neighbouring panels could abut closely enough for their tick labels to collide (PR #354)

• Multi-GPU hardening, and the configuration fix found while chasing it (PR #346)

  • The client’s configuration now reaches distributed workers. abTEM resolves configuration inside each task, and worker processes start fresh and previously saw only the YAML defaults, so any distributed computation with a non-default configuration silently used the defaults instead — most consequentially precision, which meant float64 runs were computed in float32. Distributed results obtained with a non-default configuration are worth repeating. Applies to any distributed client, CPU clusters included

  • to_zarr() on a lazy result honours dask.multi-gpu; it previously ignored the flag and ran the whole computation on a single device

  • cupy.fft-cache-size defaults to auto — 25 % of each device’s memory, resolved per device — rather than unlimited. -1 restores unlimited, 0 MB disables the cache, and a size such as 512 MB sets a fixed bound. A single plan larger than the bound runs uncached with a warning instead of raising

  • New config keys dask.multi-gpu-rmm-pool and dask.multi-gpu-devices, for an RMM memory pool per worker and for restricting the cluster to a subset of GPUs

  • Automatically sized scan batches are halved on grid sizes that force cuFFT’s Bluestein fallback, which needs a much larger FFT workspace

  • Warnings replace silent fallbacks: multi-GPU requested but declined (with the reason), a missing if __name__ == "__main__" guard, and a grid size that forces the Bluestein fallback (naming the next fast size)

Documentation:

• sampling="auto"/slice_thickness="auto" documented in detail in the potentials walkthrough, including a worked example of the commensurability artifact they remove; cross-referenced from the convergence appendix (manual commensurate sampling) and the performance-tips appendix (fast FFT sizes)

• New tutorial on phonon-loss spectroscopy: energy-resolved frozen phonons, the TDS decomposition, the momentum-resolved spectrum \(S(q, E)\), the spectral detectors and detailed-balance thermal weighting

• Energy ensembles documented in the wave-function walkthrough, with an energy series added to the multislice walkthrough

• PRISM-EELS added to the core-loss tutorial, compared against the equivalent multislice scan

• The exact free-space propagator is documented in the multislice walkthrough and the real-space multislice tutorial, which now selects the paraxial propagator explicitly where it compares algorithms at equal order

• The installation page documents the optional pip extras (gpaw, extra, all) and why the GPU packages are not among them

• The configuration reference is synchronized with the new and changed config keys

• The multiple-GPUs section of the parallelization walkthrough is expanded to cover the multi-GPU hardening fixes above, and the FFT plan-cache documentation is corrected to match the shipped auto default (it previously described a stale 0 MB default that was never shipped)

Planned for this release (not yet merged):

• Support for skewed pixels (non-orthogonal x,y,z cell axes) (PR #282)

• Radially variable detector sensitivity (PR #283)

• Plasmons: fast PhaseScramblePlasmons for multislice and PRISM, and MonteCarloPlasmons for Bloch wave

• CBED patterns for Bloch waves (PR #254)

1.0.10

Features:

• Expanded real-space multislice with propagator- and fully-corrected algorithms, and backscattered waves (PR #236)

  • Related internal function name change: standard multislice is now properly called FourierMultislice

• Updated BullseyeAperture to use smoothed aperture edges/corners (PR #266)

• Logarithmic scale display for DiffractionPatterns and images (PR #303)

• Finite-projection integrals 7x faster on CPU (PR #309)

Documentation:

• Expanded tutorial on real-space multislice

• Depth-profile visualization of potentials in the walkthrough

• Single-file Zarr zip storage, logarithmic display scaling, soft Bullseye apertures, anisotropic Debye-Waller factors and B-factor conversion helpers

• All published notebooks verified to run with this release

Dependencies:

• NumPy 2.0 or newer is now required (PR #245)

• GitHub actions based on uv and now cover more versions (including Python 3.14) (PR #308)

• New branching structure: dev for development, main for releases (only via PRs from dev)

• Support for Zarr 3 ZipStore (requiring zarr>=3.1)

  • Added Zstandard compression of the arrays in the ZipStore at default level 4 (hat tip: quantEM) (PR #252)

• Deprecated [gpu] optional dependency (as just specifying cupy will not install the correct CUDA version)

• Moved testing, docs, and dev from optional dependencies to groups

• Narrow Dask version exclusion to !=2025.12.*,!=2026.1.0,!=2026.1.1 (PR #285)

• Declared sympy as an optional dependency (core-loss extra), required for core-loss EELS form factors (PR #320)

Bugfixes:

• Frozen-phonon ensemble handling (PR #267 & PR #292)

  • May also have resulted in incorrect behavior with ensemble_mean = False for e.g. defocus distributions

• CrystalPotential with frozen phonons bugs (especially bad on – luckily rare – eager compute) (PR #306)

• Minor bugs, unsafe patterns, and dead code (PR #265)

• Anistropic Debye-Waller factors for Bloch wave (PR #271)

  • Added helper functions to convert between crystallographic B-factors and thermal sigmas

• Added missing .calculate_exit_waves for BlochwaveEnsamble (PR #294)

• Silent atom drop when z-position lands in SliceIndexedAtoms blind spot (PR #273)

• Early-exit bug in orthogonalize_cell (PR #291)

• Fixed broken tutorial workflow for core-loss filtered imaging (PR #284)

  • Minor performance improvements for transition_potential_scan (PR #286)

• Bullseye aperture: ring_width and spoke_width are now validated, rejecting values that previously produced a silently wrong (solid disk) aperture; docstring corrected to describe the actual fractional units introduced by the soft-edge redesign (PR #319)

• Unified the task-level progress bar config key on diagnostics.task_progress (Bloch-wave code paths previously read a different, non-functional key) (PR #321)

1.0.9

Dependencies:

• Support for scipy>=1.7 and cupy>=12.

• Restricted Dask versions (>=2022.12.1,!=2025.12.*,!=2026.1.*") to avoid an issue with Numba in the latest ones

1.0.8

Starting the changelog with version 1.0.8.

Features:

• Fully featured Bloch-wave simulations

• Simple real-space multislice algorithm

• Core-loss filtered imaging

• Structured illumination (custom apertures and phase plates)

Documentation:

• Updated and fixed example gallery

• Appendix on convergence

• Expanded tutorial on orthogonal periodic supercells

Bugfixes:

• Numerous small bugfixes and improvements