Changelog

Unreleased

[0.2.0] - 2026-11-07

solprop 0.2.0 adds a desktop front end, describes every run as a recipe that can be checked, saved and rerun, and retires the numba backend in favour of the native one, which is now required. Every break is listed first, under “Changed (breaking)”, with how to migrate (ADR-058).

Highlights:

• solprop-gui, a desktop front end, experimental in this release and published as a third distribution at solprop’s own version (pip install "solprop[gui]"): it sets up, runs, scans and reads simulations without a script.

• Recipes, the command line and design solvers (SEP 41): a TOML recipe for every route, the solprop command, pins that set a radius or a pressure from a zero-dispersion wavelength, a dispersive-wave wavelength or a soliton order, chosen launch modes, displaced and tilted beams, and parameter metadata for front ends.

• The native backend is required (SEP 43): numba_cpu and the numba and pyFFTW dependencies are gone, pip install solprop installs solprop-native, and new wheels cover Windows on Arm and x86-64 processors without AVX2.

• Exact resume: a file continues only under an identical configuration hash, as in 0.1.0, a refusal names the fields that differ (ADR-066), and solprop resume continues a run from its file alone.

• Output schema 2: every field of a recorded dataclass is recorded, a DataPulse keeps its phase, large record arrays are stored beside the record’s JSON, and a file no longer grows with the square of its planes. Read a 0.1.0 file with 0.1.0.

• Transverse absorbing boundaries (SEP 40): every free-space run carries a safety ramp by default, a designed real-space collar on request, and a boundary monitor that warns or stops when light reaches the edge; that edge is now read where the state lives (SEP 44), so a device run copies no state to check it.

• MLX performance: compiled stages run a trial 1.5 to 2.6 times faster on an Apple GPU, single precision admits the Adams integrator, and single-precision grids are sized for MLX’s transforms.

Changed (breaking)

The native backend replaces numba

• The numba_cpu backend, and the numba and pyfftw dependencies, are removed (SEP 43, ADR-064). backend="numba_cpu" raises BackendError, naming native and numpy_ref. A file written by 0.1.0 is refused by its output schema, as every file of another schema is: read it with solprop==0.1.0, which is also the rollback. To migrate, pass backend="native" (or leave backend="auto"), or numpy_ref for the reference.

• The settings that only numba_cpu read are gone: SOLPROP_NUMBA_THREADS, SOLPROP_NUMBA_REGIME, SOLPROP_FFTW_THREADS, SOLPROP_TRANSVERSE_FFTW_THREADS, SOLPROP_PASS_TIMERS, NUMBA_DISABLE_JIT and NUMBA_NUM_THREADS. Drop them from job scripts; they now do nothing. SOLPROP_THREADS, SOLPROP_NATIVE_THREADS, SOLPROP_FFTW_PLAN, SOLPROP_FFTW_WISDOM and SOLPROP_BLAS_THREADS stay.

• solprop-native is a required dependency, with no extra: pip install solprop installs it, and solprop is supported where it installs (SEP 43). On any other platform, including Intel macOS, ppc64le, musl and macOS before 14, the installer reports that no matching distribution exists; the installation page explains that and how to report a platform. The native extra is gone: install solprop, not solprop[native].

• backend="auto" has no fallback: it is native, and refuses with no native package or on a processor below the floor, such as Arm below Neoverse N1. A TDSE response still resolves to numpy_ref and single precision to mlx. numpy_ref stays selectable by name, as the numerical reference and for the features only it runs. Where auto refuses, pass backend="numpy_ref" explicitly.

• KERNEL_SCHEMA_VERSION and KernelProblem.schema_version are gone, and with them the kernel schema number, and solprop_native.BuildInfo.schema_version is now source_digest, the SHA-256 of the C++ sources and CMakeLists.txt the extension was compiled from: a native run’s record names it in backend.settings in place of the number. Neither enters a configuration hash or a resume check. solprop_native.check_build() takes no problem, and in an editable checkout refuses an extension built from other sources than native/, naming uv sync --reinstall-package solprop-native (ADR-068). To migrate, read build_info().source_digest where code read schema_version, call check_build() with no argument, and drop solprop.translate.KERNEL_SCHEMA_VERSION from imports and checks: solprop-native is pinned at solprop’s own version, which is now the whole contract.

• solprop no longer checks a run’s memory against a budget before allocating (ADR-065). memory_budget=, SOLPROP_MEMORY_BUDGET, estimate_memory, estimate_guide_memory, solprop.driver.memory, MemoryBudgetError and MemoryBudgetWarning are gone. A run that doesn’t fit now fails with MemoryError, or is killed by the kernel or a scheduler. Scan workers and TDSE’s memory_limit are still bounded; going over that limit raises DriverError, and it now covers atomic storage alone. Drop memory_budget= from calls and SOLPROP_MEMORY_BUDGET from job scripts; bound memory with the scheduler instead, and read Simulation.estimate() for an estimate.

Output files and resume

• The output schema is 2: a DataPulse records its spectral_phase (below), and every field of a recorded dataclass is recorded, at its default too. This release refuses a file written by 0.1.0, and every configuration hash moves, so a 0.1.0 run cannot be resumed; read such a file with 0.1.0. Code that reads a file with h5py meets these changes of layout:

  • /meta/arrays/<name>: a run record’s numeric arrays of more than 4096 elements, which /meta/json now references (below);

  • /record_arrays/: the same arrays in a scan file, shared between points;

  • /meta/outcome: a Multistep call ledger’s predictor orders as [order, count] pairs (below);

  • absorbed_power: 5 columns, where it had 4 (below);

  • a top-level recipe group in a run built from a recipe.

  Read files through solprop.output and solprop.processing where possible; they handle each of these.

• resume takes False, True or "interpolated", and any other value is a ValueError: a mistyped word used to read as True. A resume continues only on an exact configuration hash, as in 0.1.0, and a refusal now names the fields that changed (ADR-066). A changed tolerance or integrator, an optmat release, a commit that adds or moves a recorded number, and another kind of machine are all refused; a long job has to stay on one CPU family to resume, since the record holds numbers computed on the machine that built it. An appending HDF5Output holds the file’s own record as its metadata after a resume, not the one offered. To migrate, pass one of the three values; to continue under changed settings, launch a new segment from a saved plane or write a new file.

• An output file no longer grows with the square of its planes. HDF5Output rewrites /meta/outcome in place instead of deleting and recreating it at every plane, a saved plane builds and validates its run record once instead of nine times, and the step driver keeps only the error norms its controller reads, not one per accepted step: a Multistep run saved step by step (step_planes=1) costs 19.5 kB a plane at 707 planes and 19.3 kB at 3479, where it cost 23.8 kB and 31.5 kB. To get there a Multistep run’s call ledger (logical_calls and execution.response_calls in the run’s outcome, /meta/outcome in an HDF5 file) records its predictor orders run-length encoded, as [order, count] pairs, where 0.1.0 wrote one integer per accepted step. Code that read that list should expand the pairs, or read the record through CallLedger.from_record, which gives the orders step by step (#80).

• absorbed_power has a fifth channel, custom, the power a custom_absorber rate removes, and its spectral channel is now the collar alone, so a frequency-selective loss reads apart from the numerical collar. The statistic’s shape goes from (4,) to (5,); the first four channels keep their positions and their sum stays -dE/dz. Absorber.user_rate holds the user’s share of spectral_rate, which stays the total, so the operator does not move (#231). Code that read absorbed_power[..., spectral] as all the spectral loss under a custom_absorber should add the new custom column (index 4).

Free-space transverse boundaries

• A free-space run’s transverse boundary is a SpatialAbsorber (SEP 40), given as SimulationSettings.spatial_absorber or the spatial_absorber keyword of prop_radial, prop_free, prop_planar and their Simulation.from_* builders. By default every radial, Cartesian, line and planar run carries a designed safety ramp on its outer 10 % of transverse wavenumbers, folded exactly into the operator, radial and planar included; spatial_absorber=False removes it. A real-space collar is designed on request, in the grid’s room outside its requested size, from a protected band (kappa, angle, or the launch) and its width, not from the run length, and is refused by name where it cannot meet its budget. TransverseCollar, transverse_collar_rate, SimulationSettings.transverse_absorber and Absorber.spatial are removed, and Absorber.collar_length no longer sets a real-space rate. To migrate, drop transverse_absorber= for the default ramp, or pass spatial_absorber=SpatialAbsorber(kappa=...) (or angle=...) with a grid collar_fraction that leaves it room.

• Every spatial grid takes collar_fraction in place of window_factor, default 0, and puts the room it asks for outside the requested size on every geometry (SEP 40). RadialGrid’s radius is now the requested aperture, the Dirichlet boundary is at outer_radius = radius * (1 + collar_fraction), and n_r counts every sample; the transform, the nodes and the effective area use the outer radius. Fractions of 1 and more are allowed. FreeGrid(rx, nx, ry, ny) and LineGrid lose their inert 10 % margin, so their spacing at the same sample count changes; give collar_fraction=0.1 for the old grid. RadialGrid(R, n_r) keeps its wall and spacing. To keep a radial wall at R with a collar, give radius=R / (1 + c) and collar_fraction=c.

• A free-space run whose light reaches its transverse boundary now warns or stops, where it used to log and carry on (SEP 40). The boundary monitor reads the outer 5 % of the grid on every backend. It warns above 1e-6 of the launch energy and stops at 1e-4, naming a size and a sample count to try, and BoundaryCheck.transverse_budget sets those levels apart from the time window’s. The safety ramp’s removal is judged at the same levels. Its monitor record reports a transverse_status, with ramp_removed and spatial_removed. Reads are at most min(L/16, 4g/v) apart, a ceiling on the step, so a low-source run takes a few more steps. A launch with more than 1e-4 of its energy in the ramp’s band is refused. A run that now stops was losing light at its edge: enlarge the grid as the message says, request a real-space collar, or set transverse_budget deliberately.

Names, keywords and models

• Names and keywords with two meanings or two spellings are settled, with no aliases; docs/dev/conventions.md section 7 gives the rule for each. Rename the calls as listed:

  • prop_2d, time_1d and spectrogram take time_range, not trange, which stays the scalar window length on prop_*. DEFAULT_TRANGE is DEFAULT_TIME_RANGE.

  • stats.zdw and modes.base.zdw take wavelength_limits, not wavelength_range, as does wavelength_to_axis. wavelength_range is now only the attribute that says where a data model is valid.

  • bandpass and Passband take spec_range, not limits, as the plots and accessors do; Passband.limits is Passband.spec_range. A call passing the pair by position is unaffected.

  • band_coherence takes db_min, not floor_db.

  • plotting.energy and plotting.stats are plot_energy and plot_stats, the names they already had in solprop.sol.

  • backends.protocol.StepHistory is BackendHistory. Its z is each attempt’s end and output.schema.StepHistory’s is its start, so the two no longer share a name.

  • RUN_SUMMARY_ANNOTATION moves from driver.summary to output.schema, beside the other annotation names. The stored name is still "run_summary".

• DataPulse.from_time is replaced by the class TimeDataPulse: write TimeDataPulse(t=t, field=field, energy=energy). It holds the time record and has no omega, spectrum or spectral_phase. The method kept the spectrum at the record’s own bin spacing and splined its magnitude and phase, which cannot follow the fringes of pulses far apart: pulses at 100 and 600 fs in a record of 800 fs, of relative amplitude −0.9, came out 85 % wrong with no warning. The class evaluates the record’s transform exactly at the grid’s frequencies, 3e-12 from the direct sum on that case, less its mean: a baseline is an offset of the instrument, not part of the field.

• get_spectrum has no noise_floor keyword. Its annotation admitted "subtract", which it always refused: an amplitude has no part that is the floor’s power, so only get_spectral_density subtracts it. Drop noise_floor="keep", the default, from a call that passes it; the result is unchanged. A call that still passes it raises TypeError (#96).

• solprop.optics.Material refuses a temperature for a glass or a mixture with MaterialError, where 0.1.0 ignored it: drop the argument there. The temperature of Material, ModeCollection.slab and ModeCollection.vincetti now defaults to None, which a built-in gas reads as room temperature (solprop.constants.ROOM_TEMPERATURE, 293.15 K) as before; given a mixture=, slab and vincetti now take the mixture’s own temperature, where 0.1.0 refused the mixture beside its room-temperature default (#158).

• Mixture.fill, Mixture.air and Mixture.with_fill refuse floor= beside a constant pressure or a supplied ZProfile, and with_fill refuses it without a new pressure=, with a MaterialError; the simulation constructors and prop_capillary/prop_waveguide refuse pressure_floor= in the same cases. 0.1.0 accepted the floor there and ignored it. Drop the keyword where the pressure is constant or a profile; it applies only to end pressures or a stage table (#165).

• An envelope run’s frame beside a third harmonic now follows one rule, solprop.translate.responses.declares_harmonic_carrier, which translation checks against the compiled harmonic carrier (#77). Two things change for users. First, an explicit Frame(omega0, subtract_beta0=True) beside a KerrResponse or DispersiveKerrResponse with thg=True on an envelope grid is now refused with a TranslationError, where it was accepted and drove the harmonic with a spurious phase mismatch: drop the explicit frame= to take the co-moving frame, which keeps beta_0 there, or pass Frame(omega0, subtract_beta0=False). Second, a Raman response’s thg (the RamanResponse default is True), which an envelope grid ignores, no longer keeps beta_0 beside KerrResponse(thg=False) when no frame is given: such a run, built from explicit responses or on a spatial route, now removes beta_0, so its stored envelope’s carrier phase differs from before while intensities and spectral densities agree to the stepper’s accuracy, and its run record now states the frame its operator used. The keyword interfaces, which set the Raman flag from thg, are unaffected.

• mode_average=True beside tdse= is refused by name when the simulation is built. It used to build, then fail at translation with a message that did not name it; such a run never ran, so drop one of the two.

Added

The desktop front end

• The desktop front end, solprop-gui, experimental in this release: its window, its workflow and its files may change without notice before 1.0. It is a third distribution, built from gui/ in this repository at solprop’s own version; install it with pip install "solprop[gui]" and start it with solprop-gui. It sets up, runs and reads simulations without a script, and has a chapter of its own in the user guide:

  • Home offers a problem class for each common geometry (capillary, antiresonant fibre, radial filament, Cartesian and line beams, GNLSE, step-index and graded-index fibres), each starting from a few chosen examples, and a waveguide designer that needs no pulse; a recipe or results file of another route opens on a form built from solprop’s parameter metadata;

  • each class has one setup sheet, checked as it is edited, with the numbers solprop computes for it and a preview plot; a number such as the soliton order can be typed as a target, which writes the recipe’s [pins];

  • runs go in separate processes with live views, stop and resume, or in a service process that keeps them going when the window closes;

  • results are read on pages of the class, all at one plane, with plot tools (zoom, readouts, widths at half maximum, peaks) and publication figures drawn by solprop.plotting;

  • scans run a setup over a grid of its parameters, record bands, spectra and pulses, and open any point as a setup;

  • every setup saves as a recipe or shows as a Python script.

Recipes and the command line

• Recipes (SEP 41): solprop.recipe.Recipe reads a TOML description of a run, with quantities in their units ("125 um", "1.2 bar"), checks it (check(), each issue at its parameter path), builds and runs it, saves it and exports it as the Python script it stands for (to_python()). Example recipes ship with the package (Recipe.examples()). Errors and warnings that concern a value carry its parameter; writing TOML takes the tomli-w dependency. A run built from a recipe records it in a top-level recipe group of its output, as written and as resolved (the recipe that rebuilds the run). See recipes and the command line.

• Recipes on every route. The gnlse and capillary recipes came first; radial, free and planar recipes write the grids, medium, responses, beam and settings as tables of registered types (RadialGrid, FreeGrid, LineGrid, PlanarGrid, SpatialMedium, KerrResponse with gamma3, EnvelopePlasmaResponse, PlasmaResponse, OptmatRate, SpatialPulse, PlanarPulse, SimulationSettings, PIController, default_spec, SpatialAbsorber), the absorber under settings; Recipe.preview_input() gives a free-space beam’s power, energy and fluence at the launch plane, and Recipe.modes() the planar route’s slab channels. A GNLSE recipe can hold a step-index fibre: StepIndexMode, with glass or an index for its core and cladding, is its fibre, and gamma = "none" spells the None that derives the coefficient from n2 and the fibre’s area (#472). A waveguide recipe can hold a graded-index fibre: ModalGuide.on_grid builds a guide from a provider with its knots and node rule taken from the time grid, and GradedIndexProvider, PowerLawPermittivity, IndexMaterial and MaterialKerr are registered (#473).

• The solprop command (also python -m solprop) runs, checks and exports recipes, and forwards solprop scan. Simulation.run(stop=...) takes a flag that stops the run, writes its state and returns, and solprop run stops cleanly on Ctrl-C. solprop resume and solprop.recipe.resume_file continue a run from its file alone, and solprop.output.resumability says whether a file can continue, from where and with which resume=, whether it can rebuild itself, and, on request, whether the rebuilt run’s hash matches.

• Scans from recipes: a recipe’s [scan] table gives Recipe.scan(), ready for run_scan. run_scan(stop=) takes the same flag as a run: Local and Pool stop the point in flight, Pool through a message on the worker pipe, Batch between groups; a stopped point is not committed and a rerun computes it; Queue and Slurm refuse it. run_scan(progress=) accepts a solprop.log.ScanReporter (and a WatchingScanReporter for each point’s run, relayed from Pool workers).

• Design solvers for any guide (SEP 41): solprop.tools.solve_parameter finds every value of a guide or fill parameter (a radius, a pressure, a core size, a wall thickness) that meets a target, ZDW, RDW or SolitonOrder, discarding sign changes through a wall resonance, and returns them as DesignRoots with the attainable range when there is none. tools.radius_zdw inverts zdw in the radius; tools.soliton_peak_power and tools.pulse_energy give the pulse for a soliton order. A recipe’s [pins] table sets a value from such a target (Recipe.resolve(), Recipe.pin_roots()), solved at each build and each scan point and recorded with the run. solprop.grid.suggest proposes wavelength_limits and trange from the input pulses, as a starting point.

• Previews before a run: Recipe.modes() and Recipe.preview_input() show the mode set and the launched pulse. Recipe.modes() gives each mode’s beta, beta2, effective index, group delay (beta1), third-order dispersion (beta3), nonlinear coefficient (gamma), loss, effective area and zero-dispersion wavelength over the band; the new solprop.modes.base.beta3 differences the analytic beta1 twice. It also gives each mode’s phase matching to a soliton at the pump in the launch mode: the phase_mismatch of a dispersive wave in that mode over the band and its phase-matched wavelengths rdw (intermodal for every mode but the first), with the soliton’s nonlinear wavenumber where the recipe’s pulse and fill give one. The mode set says which (pump, nonlinear). The GNLSE route has a mode preview too: its one specified mode, phase-matched with the recipe’s gamma.

• Parameter metadata for front ends: solprop.recipe.parameters gives each route keyword’s forms, units, display unit, default rule and manual section, and solprop.recipe.metadata.parameters takes a registered type’s name ("GaussianPulse", "PressureGradient.two_point", "RadialGrid" and the rest) and gives its keywords the same metadata: forms with units and ranges, a level, a one-line summary, a display unit, a manual anchor and the signature’s default. solprop.recipe.metadata.per_unit_width(route, values) says when a recipe’s pulse energy and peak power are per metre of y (a waveguide recipe of slab modes), and the waveguide route’s energy and peak-power summaries say so, so a front end shows J/m and W/m there.

• Capabilities: solprop.capabilities.route lists a route’s keywords, their values and the rules that couple them, each refusal naming its rule (SolpropError.rule); solprop.capabilities.species what a gas admits: its ionisation models with their status, its Raman response, and its data ranges; and solprop.capabilities.output what a results file can give: its basis, which quantities are physical fluxes, which planes keep fields, which operations its readers refuse and why.

• Simulation.estimate() estimates a run’s memory, its output size and the cost of one right-hand-side evaluation; it is an estimate only, and nothing is admitted or refused on it. Simulation.output_bytes() is its part that times nothing: the size of a run’s output without constructing a backend, for a front end to show as the setup changes.

Example recipes and tutorials

Every route now has a recipe a front end can start from, each mirroring a tutorial built with the plain prop_* interface:

• Recipe.example("hollow_rectangular"): an argon-filled hollow silica channel in its lowest x-polarised mode, on the waveguide route.

• Recipe.example("radial_kerr"): a collimated beam in argon under the Kerr effect on a Hankel grid.

• Recipe.example("filament"): a filament in argon with plasma, with a tutorial that reads one.

• Recipe.example("line_beam"): a line beam on a LineGrid under the Kerr effect (#476).

• Recipe.example("crossing_beams"): two beams crossing in argon whose interference fringes the Kerr effect focuses, from which the desktop front end’s Cartesian class starts; a one-beam Cartesian recipe still opens, on a one-beam sheet.

• Recipe.example("step_index_fibre"), the strand of the step-index tutorial (#472), and Recipe.example("graded_index_fibre"), with a new tutorial (#473).

• Recipe.example("fibre_supercontinuum"): the canonical photonic-crystal-fibre supercontinuum of Dudley, Genty and Coen (Rev. Mod. Phys. 78, 1135 (2006), Fig. 3), also in the supercontinuum gallery, which the desktop front end lists for its GNLSE class.

• The Cartesian and planar tutorials and the planar compressor ship as examples.

Pulses and launches

• solprop.pulses.load_spectrum reads a measured spectrum from a text file (frequency or wavelength, power density, and an optional phase) into a DataPulse. A wrapped phase column is unwrapped only where the power is above a noise floor, a phase in the FFT sign convention of a Luna.jl file is read with phase_convention="fft", and a wrapped column sampled too coarsely to unwrap is warned on (SEP 41).

• prop_capillary, prop_waveguide and their Simulation constructors take launch=, which puts each pulse into chosen modes with a share and an optional phase: launch={"HE1,1": 0.9, "HE1,2": {"share": 0.1, "phase": 1.57}}, or a list with one mapping per pulse of pulses=. Modes are named as channel= names them; the shares are energy fractions, and on a guide that declares a change of basis a coordinate split scaled to the pulse’s energy under the flux metric. The run records the launch as configuration["modal_launch"], which a resume compares; a run without one records nothing (SEP 41).

• SpatialPulse takes displacement=(d_x, d_y) and tilt=(theta_x, theta_y), as coupling.Alignment defines them, applied at the launch plane on a Cartesian grid with the energy set after them; a tilt the grid’s band, window or time window cannot carry is refused, and so is either on a radial grid, a y component on a line grid, a PlanarPulse and a guide’s incident beam. A record without them reads as an unmoved beam (SEP 41).

• pulses.SpatialPulseSum launches several beams together on the free-space routes, the sum of its SpatialPulse members’ fields, each built and scaled as it would be alone: two beams crossing at an angle, a pump beside a probe. Recipes hold it (type = "SpatialPulseSum", beams = [...]), so a crossing-beam run is a recipe.

• Simulation.with_input and SimulationRunner.run take input_identity=, a string the run record holds with the array’s dtype and shape (solprop.output.StatedInput) in place of the SHA-256 of an array input’s bytes. Without it, every hash is unchanged. The identity is not checked: two different arrays stated alike have one configuration hash, so a wrong identity passes a resume and a scan’s cache. A derived run no longer digests its parent’s input to check its configuration= keys either (#449).

Routes and interfaces

• prop_waveguide and Simulation.from_waveguide take interpolate_planes and step_planes, and prop_capillary, prop_waveguide and their constructors take polarisation_taper, as prop_gnlse does; step_planes defaults to None on every interface that takes it, which on prop_gnlse behaves as its 0 did. The guide lists the deliberate differences between the routes’ keywords (SEP 41).

• Simulation.from_radial, from_free and from_planar take absorber and absorber_scheme, as prop_radial, prop_free and prop_planar and the modal from_* do.

• One table of the route defaults, solprop.driver.defaults.ROUTE_DEFAULTS, with the functions that resolve each default (default_rtol, default_integrator, default_controller, default_scheme, resolve_noise); the run record’s new defaults entry (DefaultsResolution), the start-of-run summary and the settings’ display say which of the integrator, rtol and the collar scheme took the route’s default, and the summary names a Multistep carrier frame (#87).

• precision="single" now admits the Adams integrator, Multistep() in its exponential formulation, on numpy_ref and on mlx, where its history stays on the GPU and each trial’s flow, moments and compensation are formed there in double-float arithmetic. Binary32 Adams agrees with binary64 Adams to the method’s own truncation on eight survival cases (the guide’s single-precision page has the record), and on the capillaries it is closer to the binary64 result than binary32 Runge–Kutta is. A single-precision Adams history now resumes in binary32. A single-precision run now takes each interface’s own default integrator, as a binary64 one does: Multistep() on prop_capillary, prop_radial and prop_planar, where it was RungeKutta(). (#342)

• SOLPROP_REQUIRE_DEVICE (cuda, hip or any) makes a run refuse before allocating anything unless it would execute on a native device build that sees a device, so a job doesn’t fall onto a CPU wheel that a new release installed over its source build.

• solprop.backends exports thread_budget and ThreadBudget: how many threads a process may run at once, and the limit that sets it, for a front end to show.

Output, observers and handlers

• A reporter that implements observe_plane (solprop.log.PlaneObserver) is shown each saved plane as a lazy view, whose spectrum, field, power and spectral density come from the processing functions, fetched from a device only on request; a failing observer is detached and the run completes. On a spatial run, PlaneView.stored() returns the plane’s stored spectrum (what the solprop.spatial functionals take with the run’s SpatialFlux) and PlaneView.field_plane() the plane as processing.field_plane reads it, whose spectral_energy is the beam’s energy per bin.

• solprop.output.RetainingOutput, the documented protocol for a handler of your own that takes field-free planes: its one method, retain(retention, field_shape), is called once per run, after open and before any save, with the rule resolved against the run’s planes. A run that keeps fewer than every field used to look the method up without declaring it anywhere (#450).

• solprop.output.CallbackOutput, an output handler built from a callable: it gives each saved plane to the callable and keeps nothing, so a reducing scan on SimulationRunner is a few lines and costs no volume beyond the plane’s own. check_cache, resume and resumability now refuse any output handler by name (#499).

• processing.save_field_plane and processing.load_field_plane keep a FieldPlane in an HDF5 file with its own schema version, so a saved plane can launch another run later. A recipe can’t yet name one as its launch (#456).

Free-space readers and apertures

• Readers of a radial beam from its file, in solprop.processing: on_axis_spectra, radial_spectrum, far_field, on_axis_power and on_axis_spectrogram. solprop.tools.beam_params gives a Gaussian beam’s Rayleigh range, critical power, power ratio and Marburger collapse distance, and beam_through_lens the waist a lens makes.

• processing.spatial_grid_of returns a saved spatial run’s transverse grid from its record, and processing.fluence_map lays one saved plane’s fluence out on its axes, in any bulk medium and for a file written by a script. node_fluence now also reads radial and Cartesian runs without a gas mixture. A hybrid planar file is refused by name (#455).

• solprop.spatial.spatial_energy_spectrum(spectrum, flux) splits the energy that spatial_energy measures into frequency bins, in J (J/m on a line), on radial, Cartesian, line and planar planes, and the bins sum to the total. It is not the density beam_spectrum. The coupling elements used it privately, and their reports do not change. On a spatial file, the spectral readers’ refusal now names it on every route, planar included (#184).

• solprop.spatial.spatial_power, spatial_intensity and on_axis_trace, and solprop.processing.on_axis_power, take oversampling=, resampling the time axis by zero-padding the spectrum as get_power does, so a beam’s pulse is drawn smoothly and its peak found between samples. solprop.processing.time_axis(grid, oversampling) returns the times they lie on.

• An ApertureSet row may be an ellipse, a rectangle or a half-plane (shapes, extents), with its own edge profile (profiles), so a far-field statistic can express an instrument’s mask: a knife edge at a fixed position in a far-field plane, whose wavevector moves with frequency, no longer needs the field on the host. A half-plane is half-open and tiles the columns with its complement. Line grids take half-planes bounded in x and rectangles, and the offline Aperture takes the same shapes. Unset, the new fields leave every existing result as it was (#446, part of #186).

• absorber(grid, walkoff=...) sizes the temporal collar from a group-delay drift over the grid’s own length, counted over both edges, as warn_walkoff checks, and leaves the spectral rate alone (#226). The boundaries guide now also says that boundary_N gives a slice its own strength and that boundary_length=parent.reference_length keeps the parent’s, and gives a recipe for a spectral walk-off absorber through custom_absorber, for runs whose walk-off can be predicted, with its geometry, its strength, its limits and a per-band loss check (#226).

• The Cartesian chapter gives a reading of the risk of transverse aliasing, the beam’s energy outside |k| <= k_max / 2 from region_spectrum and beam_spectrum, tested through FreeGrid runs, and states what the proxy leaves out (#216).

Plotting

• Cross-section drawings in the library (SEP 41): solprop.plotting.geometry.outline gives the outline of a capillary, antiresonant, step-index, graded-index, rectangular or planar guide, or of a radial, Cartesian, line or planar grid, as shapes in metres; draw(ax, guide, palette=...) paints it in Matplotlib, and thumbnail(route, representation, size) makes a small figure of a route for a front end’s picker. Colours come from an explicit Palette (LIGHT, DARK). The user guide’s cross-section figures draw their outlines from it.

• solprop.processing.get_spectrogram returns a plane’s spectrogram as data (gate positions, spectral axis and map, per unit of the axis asked for, with a bandpass= window), the map plotting.spectrogram draws, so a front end can draw it interactively.

• solprop.sol exports wavelength_to_axis, which the plots’ documentation sends the reader to.

Distribution and benchmarks

• solprop-native wheels for Windows on Arm (win-arm64), and an x86-64-v2 build beside the x86-64-v3 one in the Linux and Windows x86-64 wheels, chosen at import, so processors without AVX2 now run the native backend. The v2 build runs about 20 to 25 % longer by geometric mean. SOLPROP_NATIVE_CPU_VARIANT=x86-64-v2 asks for it.

• solprop-native wheels use CPython’s stable ABI, so one wheel serves Python 3.14 and later. solprop itself is not yet supported on 3.15 (#319).

• A published-install check after each PyPI release, on every wheel platform: fresh CPython 3.14 environments resolve solprop with pip and verify its version, dependencies and default backend. The same check can be run by hand for a named release, with an optional run of its tagged README example and retained logs.

• The installation page now explains how to install a development version from CI’s wheels with no compiler, and poe fetch-wheel now finds CI’s Windows on Arm wheel.

• The first performance-history rows (benchmarks/history/), recorded at 0.1.0 on six CPU and three GPU hardware sets, with numba runs beside the native ones on three of them; docs/dev/benchmarking.md lists how each is run. The history takes any backend: each row names it, and rows compare only within one backend; a run the history recorded no longer makes the next run in that checkout dirty. The benchmark harness names an AMD GPU from its PCI IDs where ROCm reports only “AMD Radeon Graphics”.

Changed

MLX and single precision

• The mlx backend compiles each stage on the GPU with mx.compile, so a stage’s element-wise passes run as a few fused kernels and its graph is not rebuilt in Python, and forms a stage’s propagator and its inverse in one kernel. A trial takes 1.5 to 2.6 times less time on the capillary, radial and Cartesian routes, measured on an Apple M5 Max, and the results are bitwise unchanged. SOLPROP_MLX_FUSED=0 evaluates operation by operation. (#343)

• The mlx backend’s Runge–Kutta march now reuses the last stage of an accepted DOPRI5 step as the first stage of the next, as native does, so a step takes six evaluations of the nonlinear source instead of seven where the temporal collar is applied in the stages. The results are bitwise the same. (#343)

• On mlx, the transverse edge is read on the GPU where no collar is requested, rather than by copying the whole state to the host at every read, and a Cartesian run’s operator is built in one pass and no longer forms an unused prefactor. On an Apple M5 Max the 384 x 384 x 750 Kerr beam takes 0.82 of native’s time, the 192 x 192 one 0.40. (#343)

• On mlx, a saved plane’s field-grid plasma statistics (the ionised fractions and peak rates at every node) are now evaluated on the GPU with the propagation’s own rate, scan and population kernels, as the envelope grid’s already were, rather than on the host in binary64 from every node’s field. On a 128 x 128 Cartesian argon filament the statistics of a plane took about 3 s and now take under 0.1 s; the values agree with the reference to about 1e-6 of their largest. (#343)

• A single-precision prop_capillary, prop_gnlse or prop_waveguide run on mlx (or backend="auto") now builds its grid for MLX’s transforms: past 4096 samples a power of two, which MLX’s GPU transforms run six to twelve times faster than the 2-3-5-smooth sizes FFTW prefers. The helium RDW capillary’s grid is 16384 fine samples instead of 10240, and a trial took a quarter of the time. FieldGrid.from_limits and EnvelopeGrid.from_limits take transforms="mlx" for a grid of one’s own, and fft_cost takes the library. Binary64 runs and single-precision runs on numpy_ref are unchanged. (#85)

• A single-precision free-space run (prop_free, Cartesian and line) now takes free space’s binary64 default tolerance, rtol=1e-4, instead of 1e-5: binary32 at 1e-4 was measured as close to a tight binary64 reference as binary64 at 1e-4 on a radial filament, a radial beam with its transverse collar and a Cartesian filament. The Cartesian filament takes 48 steps instead of 61. (#85)

GPU and native performance

• A Local scan on a CUDA or HIP build keeps its backend between points that differ only in their input, as Simulation.with_input builds them, so such a scan no longer allocates and plans a device’s backend for each point. A point’s stored results and record are unchanged to rounding.

• A lockstep Batch scan no longer moves a member’s field to the host at a plane the scan doesn’t read: BatchBackend.observe_members takes field=, as observe does, and a scan asks for what a lone point of the same scan keeps. On an NVIDIA H200 Batch(8) spent 22 % of a plane interval observing at 8 steps a plane, and on an AMD Instinct MI325X 13 to 16 %.

• A device run’s on_axis_* plasma statistics no longer copy the state to the host at each save plane: only the axis row’s spectrum crosses, and the host scans it as before (#359). StepDriver gains the _axis_row_populations hook, and _axis_statistics takes None for a backend that reads the row itself.

• A device’s low-storage step costs less beyond its transforms. On a CUDA or HIP build, a free-space envelope’s split-step temporal collar transforms every row of the state at once, in place, rather than a node chunk at a time, whatever node_budget says, and holds no coarse buffers; a flow’s lossless bin takes no exponential; and a device’s first input crosses to the scratch through tiles. At 768 x 768 x 600 a step’s collar takes 14 kernels and 10 transforms where it took 119 and 220. On an NVIDIA A40 the step fell from 2.66 s to about 2.56 s, and on an AMD Instinct MI300X a point takes 1.6 % less time. Results are unchanged to rounding (#361).

• On a CUDA or HIP build, a Kerr-only free-space envelope’s stage holds its transverse scratch in the state’s order, so its rank-3 transform keeps frequency contiguous and its input and fold no longer cross layouts. A step on an NVIDIA H200 takes 204 ms at 768 x 768 x 600 where it took 225 ms, and 36 ms at 384 x 384 x 600 where it took 51 ms, with 1.3 GiB less memory there. On an AMD Instinct MI325X it takes 199 ms where it took 211 at 768 x 768 x 600, and 52 ms where it took 57 at 384 x 384 x 600. Results are unchanged to rounding.

• On a CUDA or HIP build, a free-space run’s transforms of the transverse scratch share one work area instead of holding one each. At 768 x 768 x 600 a run holds about 16 GiB less, 22.6 GiB against 38.5 GiB on an NVIDIA A40, and 23.4 GiB on an AMD Instinct MI300X. Results are unchanged.

• On a GPU build, a large state now crosses to and from the host through a ring of pinned chunks into huge-page memory, rather than taking its page faults one thread at a time inside the driver’s copy. In a bare copy of a 5.27 GiB state that scheme reached 33 GiB/s against 1.8 GiB/s on an NVIDIA H200, and 50 GiB/s against 7.9 GiB/s on an AMD Instinct MI325X. A state under 256 MiB takes no ring, and the ring is listed in memory_ledger as host_crossing_ring. A saved plane’s finiteness check and its conversion to the stored convention now run on the process’s threads, and MemoryOutput converts straight into its own block rather than copying. Stored fields are unchanged to the bit.

• On the native backend, beam_radius and fwhm_r no longer take a time transform on a Cartesian, line or planar grid, and on a Cartesian plane they reduce where the field lives: only a few moments and one value per ring reach the host, not a copy of the fluence at every node. on_axis_intensity on a Cartesian or line grid now reads the far-field pass’s on-axis sums instead of walking every column per bin. They agree with numpy_ref to rounding. A fluence negative by a little more than its rounding budget may now be read as rounding, because the budget’s scale is a bound on the reference’s, which it reaches when the closure is proportional to the field. solprop.spatial gains FluenceRings, fluence_rings and ring_fluence_widths, the parts of cartesian_fluence_widths that a backend shares.

• A low-storage run no longer holds a state volume at its last field-free plane, so memory_ledger() and estimate() are one volume smaller, 5.27 GiB at 768² × 600. A step abandoned in flight after such a plane records failed with no terminal checkpoint and says plainly when the file cannot be resumed; a stop between steps checkpoints as ever (ADR-067, #345, #500).

• Building a large free-space launch is faster, with every bit of the launch as it was: its passes over the beam’s elements run in threads, its admittance is formed once, and the transverse residual no longer takes a Python Fraction per node. Digesting an array not held in its own order no longer builds a whole volume, so a broadcast input costs a few megabytes. (#493, #347)

Records, defaults and interfaces

• A run record’s numeric arrays of more than 4096 elements are now hashed by their bytes and stored beside its JSON: /meta/json holds a reference, and /meta/arrays/<name> the array, or /record_arrays/<name> in a scan, named by its digest, dtype and shape, shared between points. The text of a 512² Cartesian run’s record falls from about 23 MB to under 1 MB, and the first configuration hash from seconds to milliseconds, with every array still readable. RunMetadata.from_json takes the arrays as arrays=, and RunMetadata.record_arrays returns them. A noise realisation moves too (#309).

• The output schema is bumped at most once between releases, not for each change that moves it (ADR-063).

• A run asking for the zdw statistic is no longer stopped when its band holds no zero-dispersion point: the plane records nan with a warning. A direct stats.zdw call still raises, now NoZeroDispersionError, a ModeError.

• capillary_params, soliton_params and the other design tools that report a zero-dispersion wavelength find the zero nearest the pump by refining the sign changes outwards from it with array samples, not all of them, and no longer raise ValueError when the search meets a gas resonance (xenon in a 14 um capillary at 15 bar). The array refinement makes them about 2.5 times faster, and on an antiresonant fibre, whose resonances give dozens of changes, the search from the pump takes about 0.17 s where it took about 3 s; the answer is the same. Zeros clear of the gas resonances are unchanged within 1e-8; a sign change reported beside a resonance, which only a pump in the vacuum ultraviolet selects, can move within the search’s 3.6e13 rad/s sample interval.

• solprop.recipe loads its names on first use (PEP 562), as solprop itself does, so solprop.recipe.quantity, paths, document and errors import without the driver, the backends, h5py or SciPy: about 40 ms rather than half a second, for a front end that parses quantities in a process that never runs a simulation.

• solprop.backends.protocol.Backend now declares what the run layer asks of a backend, which it used to look up by name: set_stop, attach_monitor, in_flight, march_snapshot, march_snapshot_nbytes, march_export_refusal, restore_march, edge_memory, timed_step, closed and reads_transverse_edge. StepDriver defines all of them, so a backend built on it changes nothing.

• solprop.plotting draws its maps (prop_2d and spectrogram) rasterized, so a figure saved as PDF or SVG keeps its axes and text as vectors and stays small.

• The antiresonant_fibre example and the antiresonant tutorial’s propagation show resonant dispersive-wave emission: 1 µJ, 30 fs at 800 nm through 20 cm of fibre in 5 bar of argon, field resolved over 150–1600 nm with photoionisation and 201 saved planes, in place of 2 µJ over 5 cm at 1 bar on an envelope grid. They now record the default statistics, not energy alone.

Project, documentation and tooling

• The package classifier is now Development Status 4 - Beta. The interfaces may still change between minor releases.

• The README, CITATION.cff and the citing page name solprop’s Zenodo DOI, 10.5281/zenodo.23854248, which covers every release.

• Planned work has moved to GitHub issues, labelled by type, priority and area: the roadmap now lists only SEPs (ADR-062). Issue templates and CONTRIBUTING.md say what an issue or a pull request should hold and what to check before opening one.

• Notable changes are recorded in separate release-note fragments and collected into one rolling draft release PR after merges. Implementation PRs no longer edit the shared changelog, avoiding conflicts between unrelated changes. Release tags and publication remain manual.

• A plain uv sync in a checkout now compiles the native backend, and uv sync --extra native is gone. Python and documentation contributors with no compiler can use uv run --no-project tools/setup_light.py, and poe fetch-wheel installs the wheel CI built, refusing one that doesn’t fit the tree.

• Continuous integration now compiles the CUDA and HIP targets on a change to native/, with no device, so a change that breaks a GPU build is found before it merges. A build from source no longer stops on a compiler’s warning: SOLPROP_NATIVE_WARNINGS_AS_ERRORS now follows BUILD_TESTING, so it stays on for the presets and is off for pip and uv builds, while continuous integration keeps it on for its wheels. (#151)

• Corrected the mixtures guide on spatial fluence and on who refuses a z table, three worked examples’ prose, how ReferenceState.temperature reads where a source declares none, and what the antiresonant guide claims for the dispersion width’s fit to the finite-element solutions.

Fixed

Noise, scans and resume

• A scan derived from one cached simulation, the scans guide’s own recipe, now gives every point its own noise seed. with_input(noise="keep") and with_mixture keep the ability to draw unseeded noise again, and the draw replaces only the initial noise of the shared translation. Before, such points shared the base’s draw, depended on the worker under Pool, could not be rerun in a new process and failed under base_seed. Resuming a derived, unseeded run now takes the file’s seed, as a constructor’s does, instead of being refused.

• One object returned by a scan builder for every point no longer collapses a noise ensemble under Batch, where every member ran on the last point’s noise while the file recorded each point’s own seed. The draw now goes on a copy, and the builder’s object is left as it is. A file written by such a scan holds the wrong noise for its recorded seeds and a rerun does not detect it: run those points again.

• Resuming a file that holds only its launch plane, from an input-noise run stopped before its first saved plane, no longer adds the noise draw to the stored field a second time, which had doubled the noise amplitude for the rest of the run on every backend. set_initial takes resume=True for a stored field.

• A scan file whose points’ run records declare another output schema, a 0.1.0 scan among them, is refused by name, in the words a run file is refused with, when it is read (ScanOutput, read_point) or resumed or collected (run_scan, a queue’s collector). Before, only the scan container’s own version was checked, and that stayed 1, so such a scan was read as if its layout were this release’s.

• A recipe with a [scan] no longer drops the [execution] keys run_scan does not take: resume_history now reaches each point’s settings, as the scan file’s recorded recipe says it does.

• stop= now stops a native Multistep() run during its march instead of at its next save plane: within a native call’s bound, 256 attempts or 0.1 s, and the attempt in flight. With one plane the flag was ignored and the run finished as complete. solprop run and solprop resume, whose first SIGTERM or Ctrl-C reaches a run through that flag, stop the same way; they used to report a stop that the file showed had not happened (#519). A signal that comes too late to stop the run now exits with status zero and says the file is complete (#521).

• On Windows on Arm, Pool scans no longer fail or hang in NumPy’s linear solves. Workers now limit BLAS through threadpoolctl instead of thread variables, which crash or hang NumPy’s OpenBLAS on that platform at small widths, and import solprop warns if such a value is set.

Boundaries and the monitor

• Under absorber_scheme="split_step", the default on the spatial routes, the boundary monitor judges the time window’s guards on the power each step’s split finds, halfway through its factor, instead of the state it leaves, whose guards it had damped by about e^-10: a pulse walking out of the window is now stopped where the in-stage scheme stops it (#127). Each reading reports that power’s energy and its guards’ and collar’s energies (solprop.monitor.BoundaryEnergies.found) and the state’s energy per walk-off bucket (BoundaryEnergies.occupancy). Steps are also held to the split collar’s crossing limit, half the collar’s width over the walk-off of the fastest light holding more than 1e-6 of the energy, so that no step carries light through the collar and round the window undamped (issues #149 and #440). It is read from the launch at translation, which holds dz_max and refuses a longer fixed schedule, and again from the state at every check, which caps the steps after it and stops a fixed schedule it falls below. See absorbing boundaries.

• Under input noise, the boundary monitor subtracts at most one floor from the collar’s removal: the floor is put in once at the launch and cannot lose more. It subtracted the floor’s rate over the whole run, about 37 floors under the default collar, so a removal of a few 1e-3 read as zero, with no warning, and the split scheme’s subtraction grew with the number of steps (#126).

• A resumed run’s monitor record continues from the latest execution that kept one: a second hard kill before the monitor started, or an execution with boundary_check=None, no longer restarts the totals, and the stretch run unwatched is listed under unwatched. The signed removal is kept and restored, so a stop and resume reads as the whole run; the quiet collar’s state is restored; and a resume on a held row no longer counts the resumed state in the next row’s guard maxima (#128).

• BoundaryCheck(quiet_collar=True) no longer records the collar as left out on the Cartesian, line and planar routes, whose stages keep it, or caps their steps for nothing (#94).

• A scan point keeps its closing boundary-monitor record, without the per-plane rows, under every executor (read_point(...)["boundary_monitor"]); a batched point no longer stores the launch’s zeros; and a BoundaryWarning raised as an error fails its own batched point alone, as under Local (#132).

• The default boundary check no longer brings a native run’s state to the host. The transverse edge, a requested collar included, is read where the state lives and only numbers cross, so a field-free run on a device copies no state at all, and on the CPU a free-space Kerr beam’s check costs less. A resumed run with a requested collar now restores its current, baselines and peaks, so it no longer judges against zero. (SEP 44, #385, #512)

• The default boundary check no longer does work that nothing uses. A saved plane the step that reached it already read takes no second read, which on a device was a copy of the whole state. A fixed schedule’s reads of the transverse edge now follow its next step rather than dz_init, which read one step late with a short dz_init, past the spacing the reads promise, and at every step with a long one. The split collar’s occupancy reduces per column, without an atomic per element, which took most of a monitor reading on a GPU. energy and peak_intensity no longer sum on one GPU thread, an Adams run over the snapshot limit takes no snapshot to learn its size, and a runner’s points share the walk-off table rather than upload it each.

• A boundary monitor built for another grid is now refused by name on every backend, instead of a bare ValueError on native and an accident in matmul on numpy_ref. A direct call to native’s stats now checks every route for names the route doesn’t define, and refuses a general flux statistic under a weight other than one rather than ignoring the weight.

• warn_walkoff suggested a boundary_N counted from the default strength when it was given a boundary_length; it now counts from the length in force. The guide and the docstring of no_absorber no longer say that an explicit absorber switches on a free-space run’s real-space collar or that the collar reads the reference length (#226).

• Documented the limits of FixedSchedule.from_history. Every collar refusal a replayed history can reach (the temporal collar’s stable step, and a requested spatial collar’s stable step and its fixed-schedule crossing and damping bounds) now prints its limit rounded down and names the remedy: dz_max at or under the printed limit in the discovery run, run with the replay’s integrator where the limit is a stability limit, or, for the temporal collar alone, absorber_scheme="split_step" in both runs. The docstring and the fixed schedules guide state these limits and the interpolated-plane and non-abutting-history ones, relate from_history to discover, and replace the claim that a Multistep replay makes its adaptive run’s truncation errors: compare two replays of one schedule instead, and for a comparison of the arithmetic alone replay with fixed orders (RungeKutta() or Multistep(variable_order=False)), since a variable-order replay’s order choice can turn on rounding (#82).

Copies and memory

• A Simulation built from an array input now copies the array at construction, so changing it before the run no longer changes the run, its construction-time checks or its recorded configuration (#434). Simulation.initial is a read-only view of that copy as the caller gave it, so an input of another dtype is recorded unchanged and older files resume. On free-space and spatial routes the translated problem holds the same copy; on a modal route it holds the converted launch beside it, two states. A numpy.broadcast_to input copies only the block it repeats.

• A translated problem no longer holds a full copy of a broadcast initial field (#5): a numpy.broadcast_to placeholder, of any numeric dtype, costs only the block it repeats. Every other initial field, noise realisation and batch parameter is now copied, so changing the caller’s array after translation can no longer change the problem, and the caller’s array is no longer made read-only; before, a contiguous complex128 field and a noise realisation were shared with the caller.

• The native backend no longer keeps the last host state it loaded alive after set_initial: a temporary, such as an input noise sum, a resumed plane or a delay scan’s input, was one host field volume held until the next load, outside memory_ledger(). A resident Adams march no longer keeps a host copy of the state for the backend’s life either; solprop’s host engine, which reads one, lists it as adams_host_state (#435).

• A SimulationRunner no longer holds an input through its march. An array recorded by its digest is read in place rather than copied, and neither it, the launch converted from it nor the derived simulation outlives the load, so a delay scan that forms each input in the call holds it only until the backend has it (#447).

• A run hands its output each plane without copying the field. SavedPlane copied an observation’s field, and again when the driver added the plane’s statistics, so a handler that only reduces a plane paid two field-sized copies and a peak of two volumes per plane. plane.field is read-only and nothing changes it afterwards, so a handler can still keep it; a SavedPlane constructed by hand copies, as before (#448).

• A run of a guide that is the same along its length (a fixed fibre, a uniform fill) records its mode basis once instead of once for each saved plane, so a step-index fibre with 201 saved planes now starts at once rather than after about 95 s.

• A run into MemoryOutput, the default handler, no longer computes the configuration hash for a debug message that is switched off, which took seconds on a large grid.

• Guide and incident-plane construction, kernel translation and coupling now limit NumPy’s and SciPy’s controllable BLAS pools to one thread, or SOLPROP_BLAS_THREADS within the process budget, and restore their previous limits afterwards. This prevents the thousands of small graded-index eigensolves from occupying every CPU before a backend starts. Vendor thread defaults are overridden only during construction; the native backend’s own BLAS keeps its fitted width.

Pulses, modes and design tools

• A tilted SpatialPulse travels towards +x (+y) for a positive tilt, as documented and as coupling.Alignment tilts a beam; it went the other way. Scripts that compensated by negating the tilt must remove the minus sign.

• DataPulse.from_spectral_density interpolates the phase it is given. It used to wrap the phase into the complex spectrum and unwrap it again, which cannot follow a change of more than pi between samples, so a strongly chirped pulse was built wrongly with no warning: 20 000 fs² of group-delay dispersion on a 0.4 nm axis at 800 nm came out 13.5 % away from the converged spectrum, on a 1.6 nm axis 100 %. A DataPulse given a complex spectrum still unwraps it, and its docstring states that limit.

• A measured field in time puts a pulse where it sat in the record (TimeDataPulse, above). DataPulse.from_time unwrapped the phase, and a pulse more than half the record’s length from t = 0 changed its phase by more than pi per bin, so it was moved by one record length with no warning: at 500 fs in a record from 0 to 800 fs it came out at −300 fs.

• StepIndexMode builds fibres up to V = 20000 and refuses larger ones with a message that says so; it refused most fibres above V of about 26, a 100 µm core of numerical aperture 0.22 at 1030 nm among them, because its root scan lost close pairs of HE and EH roots, and from a cladding argument of about 700 the unscaled modified Bessel functions underflowed. It also refused every EH family from an azimuthal order of about 40, where J_n underflowed at small u. The lost roots are now bracketed by each family’s own factor of the characteristic product; the scan runs from the family’s first cutoff to the one above the requested radial order, so a low-order mode costs the same at any V; and the modified Bessel ratios and exterior fields use the exponentially scaled functions, with a recurrence where those overflow at large order. Effective indices below V = 26 move by at most one rounding (#148).

• tools.lambda_rdw_all skips a sign change of the phase mismatch through a resonance of the guide, where the mismatch has a pole or is not a number, instead of raising a bare ValueError from SciPy on an antiresonant fibre’s default search window (#538).

• A soliton_order pin on a GNLSE recipe reads the recipe’s gamma or n2, where it failed with a bare AttributeError looking for the mode’s gas fill.

• A recipe without a required keyword now raises RecipeError, naming the keyword in its parameter, from build, resolve, modes, preview_input, pin_roots and run, where the route’s constructor raised a bare TypeError (#454).

• The step_index_fibre example and its tutorial run 5 cm on a 2 ps window with the boundary monitor on, saving 201 planes; over 15 cm on 1 ps its Raman-shifted solitons left the window unnoticed and the run lost 71 % of its energy (#544). The rdw, spm_compressor and graded_index_fibre examples and their gallery scripts save 201 planes, for smoother plots along z.

Readers and plots

• On a radial, Cartesian, line or planar output, the processing readers that read each transverse column as a modal amplitude in sqrt(W) now refuse the file by name with an OutputError that names the spatial functional to use, instead of returning wrong numbers silently (a 3 nJ launch read back as 4.8e-15 J). They are energy, peak_power, get_power, get_spectral_density, fwhm_t, fwhm_f, time_bandwidth, arrival_time, field_autocorrelation, intensity_autocorrelation and coherence_time, the plots prop_2d, time_1d, spec_1d and plot_energy, and a plane observer’s power and spectral_density. Use solprop.spatial.spatial_energy, spatial_power and their neighbours on a saved plane, or the run’s stats/energy, which is unchanged; get_spectrum, get_field and get_phase still return the stored columns. solprop.capabilities.output gains refused_readers, which states these refusals with the readers’ own text, while it still admits a spatial file’s energy statistic. Modal files read as before (#147, #406).

• get_spectrogram, and so plotting.spectrogram, no longer alias on a narrow envelope grid. The real field is now oversampled until it resolves the carrier: an 800 nm pulse on a 600 nm to 1100 nm band used to appear near 2.9 µm.

• Bad input to the processing and plotting helpers is refused by name, with its units, instead of failing late or silently. Passband refuses other than two limits, or a width that is not positive, when built; it raised IndexError on use, or kept two of three limits. wavelength_to_axis refuses a wavelength limit that is not positive on a frequency axis, where zero raised ZeroDivisionError. spectral_bands and band_coherence refuse n_bands below one, and a band with nothing to average stays nan without a RuntimeWarning. spectrogram refuses a spec_range that misses the data, as get_spectral_density does, instead of drawing an empty view (#96).

• A gallery page re-run on its own keeps its MaterialRangeWarning: the docs build’s import of solprop.sol silenced it for every script after.

Backends, single precision and platforms

• An adaptive RungeKutta() run on mlx is no longer held to short steps by binary32’s exponent range: a trial whose collar or loss would overflow the interaction picture’s inverse propagator (|Re dPhi| past 88.7) is combined in the lab frame by forward flows instead, where it was rejected and shrunk before. A radial Kerr beam whose first trial reaches 459 now takes its millimetre in one step, as binary64 does, against 14 steps and 2 rejections. Runs within the range are unchanged. (#343)

• A single-precision run with the low-storage march or the exponential Adams method is no longer refused when a step’s damping exceeds binary32’s exponent range: those methods apply forward flows only, which underflow harmlessly in a damped bin, so only growth is limited. The Cartesian Kerr beams’ replayed 0.5 µm steps, refused before on their spectral collar, now run in binary32 and agree with binary64 to 2e-7. The check uses the operator’s rate bounds on the free-space and radial routes instead of forming the operator over the grid (seconds at 384 x 384 x 750). (#343)

• Fixed the reference’s single-precision path leaving binary32 on two paths that it then narrowed without a check: the split-step collar now keeps a complex64 state in binary32, as the correction a + F(F^-1(a)(f - 1)) that mlx uses (binary64 runs are unchanged), and a fixed-schedule batch of single-precision numpy_ref members now steps each member through its own binary32 trial instead of the binary64 batch arithmetic, and a lockstep batch refuses members of mixed precisions. The finished state is now refused by name if it is not complex64 (#79).

• Simulation.estimate() no longer crashes the process on the native backend under LowStorageRungeKutta(), and on every backend it now times that march’s own step, so its time per step is the low-storage march’s (#492). A trial step on a native low-storage state now raises a named error instead of faulting.

• The native backend now refuses an unknown SOLPROP_FFTW_PLAN value, which it had read as measure, and a problem whose response_order omits a response it holds, which it had run anyway. An empty SOLPROP_FFTW_PLAN now counts as unset (#460).

• A native run under Runge-Kutta or Adams now records the propagator_mode it used, recompute, when tabulate was asked for; it had recorded tabulate, which that march can’t do. The run’s configuration still keeps what was asked (#464).

• On an AMD device, the far-field pass decided about 3 % of the columns exactly at a hard aperture’s edge differently from numpy_ref, because the compiler fused products and sums the pass meant to round separately. The radius is now rounded as on every other build.

• The native backend’s HIP build compiles again under its default warnings-as-errors: ROCm’s Clang refused a thread-local variable that only an OpenMP build uses (0.1.0 needed -DSOLPROP_NATIVE_WARNINGS_AS_ERRORS=OFF).

• With /proc/cpuinfo unreadable, native chose its x86-64-v3 build, so a lower processor could reach an illegal instruction (#443). It now asks NumPy, and refuses before loading if neither answers. The Windows on Arm wheel gains a processor check too, for the Armv8.2-A OpenBLAS it links.

• The versions of solprop, solprop-native and solprop-gui now come from v* tags only, so another tag on a commit can no longer set them. Building any of them now needs setuptools-scm 9, and solprop-native requires NumPy 2.5, as solprop does (#92).

• poe tasks now run in the environment poe was started in, so uv run --no-sync poe fetch-wheel no longer tries to build the native backend first, and uv run --no-sync poe test no longer replaces a fetched wheel with a local build. The contributor guide now gives the command that works with no compiler.

• Building the native backend records why the macOS refusal after pyFFTW stays and what would lift it, and no longer says that importing solprop first avoids it: importing solprop does not load the backend (#315).

• Correct the 0.1.0 limitation statement about mlx: its custom Metal kernels already run in continuous integration’s macOS default lane. That lane now requires Metal, so losing the device fails the job rather than silently skipping the kernel tests. MLX coverage, runtime type checks and an explicit CPU-device pass remain absent.

[0.1.0] - 2026-10-31

The first public release of solprop and of its compiled backend, solprop-native, which is released at the same version. Releases are 0.x for now: a minor release may break the API, the output schema or the resume key, and lists every such break under “Changed (breaking)” (ADR-058).

Added

• Propagation equations. The unidirectional pulse propagation equation (UPPE) and the generalised nonlinear Schrödinger equation (GNLSE), for the real electric field or a complex envelope, in waveguides and in free space.

• Waveguides.

  • Gas-filled hollow capillaries, with resolved modes (the default) or mode-averaged (mode_average=True on prop_capillary and prop_waveguide). Tapers, pressure gradients and gas flow are supported, as is a coherent wall that couples the modes.

  • Antiresonant hollow-core fibres (the Vincetti model).

  • Step-index, graded-index, rectangular and planar guides.

  • Modes tabulated from arrays or from external mode solvers.

  • A general modal route for any guide that supplies its own electric and magnetic mode fields, including guides that change along their length.

• Free space. Radial, Cartesian and line grids with the exact (non-paraxial) diffraction operator; planar guides can be resolved across their width. Launches, shot noise, energies, fluences and intensities measure the medium’s axial Poynting flux at the plane, so a requested energy is the physical energy there (SEP 34). Far-field and aperture statistics.

• Media and responses.

  • Gases, gas mixtures, glasses and metals from the optmat material library.

  • Kerr and third-harmonic nonlinearity, including a dispersive electronic response.

  • Photoionisation with atomic and molecular rate models, and plasma on field and envelope grids.

  • Rotational and vibrational Raman responses, scalar and vector.

  • Quantum shot noise, on by default (SEP 37): one photon per mode with a random phase, added to the input field (noise="input") and recorded with its seed. A resumed run draws the same realisation again, and a scan draws each point’s from a seed of its own. noise=None switches it off and noise="modified" keeps the realisation apart from the field. The Cartesian, line and hybrid planar grids, slab mode sets, the TDSE response and single precision carry none by default and record why. Spectral densities can subtract the one-photon floor (noise_floor="subtract").

  • An optional helium TDSE atomic response for research. Its native backend is not yet publicly available.

• Integrators and their defaults.

  • Two adaptive integrators: a low-call exponential Adams method (Multistep()) and an embedded interaction-picture Runge–Kutta pair (RungeKutta()), with a low-storage Runge–Kutta variant and fixed schedules. The linear propagation is integrated exactly.

  • Each interface has its own default integrator and tolerances, chosen by measurement: RungeKutta() for prop_gnlse (rtol 1e-7), prop_waveguide (1e-5) and prop_free (1e-4); Multistep() for prop_capillary (1e-6), prop_radial and prop_planar (1e-5). The choosing-a-stepper page tabulates them and says when to choose another.

  • Multistep(carrier_frame="scalar"), an opt-in carrier frame for the Adams history that is the fastest method measured on dense, multimode, Raman-active runs such as a comb-to-continuum capillary (SEP 35).

  • Backends agree with each other to bounded, rounding-level differences.

• Time-window boundaries (SEP 21). Every interface absorbs at the edges of the time window and of the spectrum. The temporal collar lies outside the requested window: the grid widens to trange / (1 - 2 collar_fraction) (collar_fraction 0.1), so the whole request is flat, and transform sizes default to fft_size="auto", the cheapest 2-3-5-smooth size up to the next power of two. absorber=False switches the soft collars off and keeps the same grid. A boundary monitor, on by default (boundary_check= on every prop_* function and Simulation.from_* constructor), warns (BoundaryWarning) and then stops the run (BoundaryError) when light above the shot-noise floor reaches the window’s edge, and records the energy the collar removed.

• Coupling simulations (SEP 31). solprop.coupling hands a field from one simulation to the next. A FieldPlane holds a coherent field at one plane with its reference and provenance; couple maps it into another simulation’s InputPort under a declared CouplingModel and returns an energy report; transport carries a free-space plane through lenses, apertures, masks, mirrors, interfaces and spectral filters; Outcouple synthesises a guide’s exit field. An incident beam launches into a general modal guide with the share of its energy that the guide captures. Each step is admitted against an error budget and refuses what it cannot certify.

• Backends.

  • numpy_ref, the NumPy reference, against which every other backend is tested within derived error bounds, and numba_cpu, compiled with Numba. The backends come in tiers: new features land on numpy_ref and native; numba_cpu is mature and takes a new feature only where its design says so; mlx is experimental.

  • The optional native backend, the solprop-native distribution: C++20 kernels on Kokkos for multi-core CPUs (OpenMP) and for NVIDIA and AMD GPUs (CUDA, HIP). pip install "solprop[native]" installs a precompiled CPU wheel on macOS on Apple silicon, Linux on x86-64 and aarch64, and Windows on x86-64. backend="auto" selects it when installed, except on a processor below the wheel’s CPU baseline, where it uses numba_cpu and warns once (SEP 29). On the native backend the exponential Adams march runs in compiled code, many steps per call (SEP 39).

  • One thread budget per process, which every pool of both CPU backends stays within: the smallest of the CPU affinity mask, the physical cores that hold it, the control group’s CPU quota and SOLPROP_THREADS (ADR-052).

  • Single precision (SEP 33): precision="single" holds the state, the transforms and the responses in binary32, with the controller in binary64. numpy_ref runs it as the reference, and the mlx backend (pip install "solprop[mlx]") on the Apple GPU. A survival record states which problems keep their accuracy.

• Running and recording.

  • HDF5 output with periodic snapshots and provenance, and resuming an interrupted run, which continues the Adams history.

  • A summary at the start of every run of what it is about to compute (the code, the machine, the backend, the grid, the medium, the responses, the noise, the integrator, the absorber and the output), and at its end the wall time, CPU time and peak memory. Each execution records its machine and what it spent in the file.

  • Statistics along the propagation.

  • Parameter scans on process pools and Slurm clusters.

• Analysis and tools.

  • Processing and plotting. Spectral ranges and band-pass windows are given in the units of any spectral axis (spec_range, Passband).

  • Ensemble coherence by spectral band, and replay of a run’s accepted steps (FixedSchedule.from_history), to compare two precisions or backends on one discretisation.

  • Soliton and dispersive-wave design tools.

  • Pulse compressors: Taylor phase, chirped mirrors, materials, gratings and prisms.

  • An interactive session through import solprop.sol as sol.

• Performance tracking for developers (SEP 38): python -m benchmarks track times about a dozen representative workloads, with each interface’s defaults, at one thread and at the production width, and records them by hardware; python -m benchmarks ab compares two builds.

• Documentation. An introduction with executable lessons, a user guide, a long-form primer on the physics and numerics, focused tutorials and worked examples, the API reference, and a developer’s guide with the design records (SEPs and ADRs).

Changed (breaking)

Nothing was released before 0.1.0. For scripts and files from a development checkout:

• Output files of development versions are not read. The output schema restarts at 1 (solprop.output.SCHEMA_VERSION); keep the development install that wrote such a file to read it. The kernel contract’s version is KERNEL_SCHEMA_VERSION, separate from it.

• Defaults changed late in development, so a development script’s results change: shot noise is on; each interface takes its own integrator and tolerances; the temporal collar lies outside the requested window, which widens the grid (collar_placement="inside" rebuilds the former geometry); transform sizes are fft_size="auto"; and the boundary monitor is on.

• Renamed or removed. prop_gnlse, prop_capillary, prop_waveguide and their Simulation.from_* constructors take wavelength and shape, not lambda0 and pulseshape, and responses_for takes wavelength, as the pulses and the design tools already did. The plots’ wavelength_range is spec_range, in the units of their axis, and solprop.plotting.style.spectral_limits is gone (wavelength_to_axis converts a wavelength range); bandpass takes limits, not wavelength_limits; poynting_spectrum is gone (beam_spectrum is the axial-flux spectrum); the same_basis function is gone (use couple); and solprop.driver no longer exports propagate_fixed_rk4, the tests’ fixed-step oracle. Multistep() refuses the PIController settings it does not read.

Known limitations

• The mlx backend is experimental. Its Metal kernels are tested by hand on a Metal device, not in continuous integration, and its coverage is not measured there. The single-precision survival record is the reference implementation’s (on mlx for two cases). On the default fft_size="auto" grids MLX’s GPU transform runs four to eight times slower than on powers of two, so a run can be slower than binary64 native: build single-precision grids with fft_size="pow2". The guide’s speed table predates the current grids and is marked so.

• Free space has no accurate transverse absorber. By default a radial grid’s edge is a hard wall and a Cartesian or line grid wraps around; the optional real-space collar (an absorber given to a spatial run, Absorber.spatial) removes only part of the light that reaches it, at a large cost in steps, and the boundary monitor watches the time window only. Size the transverse window so that the light stays clear of its edge. SEP 40 (a draft) rebuilds these boundaries.

• A run is resumed by the release that wrote it. A run’s configuration hash covers every recorded field, so a release that adds one changes every hash, and within 0.x the output schema may change too: finish a run with the release that started it.

• GPU builds are made from source. The wheels are for CPUs; CUDA and HIP builds of solprop-native are built from the repository (building the native backend).

• CPython 3.14 only. solprop-native, pyFFTW and h5py have no wheels for 3.15 yet.

• macOS: import solprop before pyFFTW. pyFFTW’s macOS wheel starts its own OpenMP runtime, so the native backend refuses to load in a process that imported pyFFTW first; solprop itself imports them in the working order.