phasma

Terminal interface for the caustic Vlasov-Poisson solver.

---

phasma is a terminal application built with ratatui for setting up, running, and monitoring 6D Vlasov-Poisson simulations using the caustic solver library. It runs entirely in the terminal — over SSH, in tmux, on headless compute nodes.

It provides real-time density and phase-space heatmaps, energy conservation charts, radial profiles, performance dashboards, history scrubbing, batch execution, parameter sweeps, convergence studies, playback, comparison, and export — all without leaving the terminal.

Note: This application has not yet reached version 0.1.0. The interface and configuration format are unstable, features may be incomplete or change without notice, and it is not yet intended for general use. Even after 0.1.0, until version 1.0.0 it should not be relied upon for production workloads or serious research.

Installation

From crates.io

cargo install phasma

From source

git clone https://github.com/resonant-jovian/phasma
cd phasma
cargo build --release
./target/release/phasma

Man page

phasma --generate-man > phasma.1
sudo mv phasma.1 /usr/share/man/man1/

Dependencies

• caustic — the solver library, pulled automatically as a cargo dependency
• ratatui + crossterm — terminal rendering (no external deps)
• Rust 1.85+ (edition 2024)

Quick start

# Launch the TUI — browse and load configs from the Setup tab
phasma

# Load a preset and start immediately
phasma --config configs/balanced.toml --run

# Headless batch mode for HPC / SLURM
phasma --config configs/nfw_high_res.toml --batch

# Verbose output — see every build step and per-step diagnostics
phasma --config configs/balanced.toml --run --verbose

# Replay a completed batch run
phasma --playback output/run_20260310_143022/

A minimal config:

[model]
type = "plummer"

All fields have sensible defaults. Smart defaults auto-fill boundary conditions, Poisson solver, domain extent, and t_final based on model type.

Modes of operation

Mode	Flag	Description
Interactive TUI	(default)	Browse configs, run, monitor live
Auto-run	--run	Load config and start sim immediately
Batch	--batch	Headless, saves to disk, suitable for HPC
Playback	--playback DIR	Replay saved snapshots with scrubbing
Comparison	--compare DIR DIR	Side-by-side two-run comparison
Monitor	--monitor DIR	Watch a running batch job live
Tail	--tail DIR	Like monitor, auto-advances
Wizard	--wizard	Guided interactive config generation
Sweep	--sweep TOML	Parameter sweep (Cartesian product)
Convergence	--convergence TOML	Resolution convergence study
Regression	--regression-test DIR	CI-compatible regression test (exit 0/1)
Batch compare	--batch-compare DIR...	Markdown comparison report

CLI reference

Flag	Argument	Description
-c, --config	PATH	Path to simulation config file (TOML)
--run	—	Start simulation immediately
--batch	—	Headless batch mode
-v, --verbose	—	Detailed logging of every build step and per-step diagnostics. In batch mode prints to stderr; in TUI mode appears in the F2 log panel
--playback	DIR	Replay saved snapshots in TUI
--compare	DIR DIR	Side-by-side comparison of two runs
--sweep	TOML	Parameter sweep
--convergence	TOML	Convergence study
--regression-test	DIR	Regression test (exit 0 on pass, 1 on fail)
--monitor	DIR	Watch a batch job's output directory
--tail	DIR	Like --monitor, auto-advances to latest
--wizard	—	Interactive config wizard
--save-preset	NAME	Save loaded config as a named preset
--batch-compare	DIR DIR [...]	Markdown comparison report across runs
--report	PATH	Output path for --batch-compare (default: comparison_report.md)
--generate-man	—	Print roff man page to stdout

Verbose mode

--verbose / -v enables detailed logging during simulation startup and stepping:

  [verbose] Loading config from: configs/balanced.toml
  [verbose] Config loaded: model=plummer, repr=uniform, poisson=fft_isolated, integrator=yoshida
  [verbose] Domain: spatial_extent=10, velocity_extent=3, N_x=16, N_v=16
  [verbose] Phase-space grid: 16^3 × 16^3 = 16777216 cells (128.0 MB)
  [verbose] Boundary conditions: isolated|truncated
  [verbose] Building domain...
  [verbose] Domain built in 0.3 ms
  [verbose] Building IC: model=plummer, M=1, a=1
  [verbose] IC sampled in 1842.1 ms — 8388608 non-zero cells out of 16777216
  [verbose] Building phase-space representation: uniform
  [verbose] Representation built in 0.0 ms
  [verbose] Building Poisson solver: fft_isolated
  [verbose] Poisson solver built in 12.4 ms
  [verbose] Building integrator: yoshida
  [verbose] Assembling simulation: G=1, t_final=15, cfl=0.35, conservation=none
  [verbose] Simulation assembled in 45.3 ms
  [verbose] Exit conditions wired: 3 active (energy_drift_tol=0.5, mass_drift_tol=0.1)
  [verbose] Build complete in 1902.8 ms

In TUI mode these messages appear in the F2 Run Control tab log panel. Per-step verbose messages show step number, time, timestep, wall time, and energy drift.

Batch output directory layout

output/<prefix>_YYYYMMDD_HHMMSS/
  config.toml          -- copy of input config
  diagnostics.csv      -- time series (appended each step)
  snapshots/
    state_000000.json   -- periodic SimState snapshots
    state_000001.json
    ...
    state_final.json    -- last state
  metadata.json         -- version, timing, exit reason, snapshot count

This directory is the input for --playback, --monitor, --compare, --regression-test, and --batch-compare.

TUI tabs

Tab	Key	Content
Setup	F1	Config browser, structured config summary, memory estimate, preset selector (Ctrl+P)
Run Control	F2	Progress gauge, aspect-corrected density/phase-space thumbnails, energy chart, diagnostics sidebar, log stream
Density	F3	2D projected density heatmap with aspect correction, axis selection (x/y/z), zoom, log scale, contour overlay
Phase Space	F4	f(x_i, v_j) marginal projections for all 9 dimension pairs, physical aspect ratio (default on, p to toggle), data cursor
Energy	F5	Conservation time series: E(t), T(t), W(t), drift, mass, Casimir, entropy — 4 panels
Rank	F6	HT/TT rank evolution, per-node table, singular value spectrum, truncation error (dimmed when repr=uniform)
Profiles	F7	Radial density, velocity dispersion, enclosed mass, circular velocity, anisotropy, Lagrangian radii, analytic overlays
Performance	F8	Step timing breakdown, adaptive timestep chart, memory breakdown, cumulative wall time
Poisson	F9	Poisson residual, potential power spectrum, Green's function detail (dimmed when poisson != fft_isolated)
Settings	F10	Theme and colormap selection

Keyboard controls

Global

Key	Action
F1–F10	Switch tabs
Tab / Shift+Tab	Next / previous tab
Space	Pause / resume simulation
Left / Right	Scrub backward / forward through history
Backspace	Jump to live (exit scrub mode)
?	Toggle help overlay
e	Open export menu
T	Cycle theme
C	Cycle colormap
Ctrl+S	Save current config to TOML file
Ctrl+O	Load config (jump to Setup tab)
/	Jump-to-time dialog
:	Command palette
a	Add annotation at current time
Ctrl+B	Toggle bookmark panel
q	Quit (with confirmation if sim is running)

Run Control (F2)

Key	Action
p / Space	Pause / resume
s	Stop simulation
r	Restart simulation
1–3	Log filter: all / warn+ / error only

Density (F3)

Key	Action
x / y / z	Change projection axis
+ / - / scroll	Zoom in / out
r	Reset zoom
l	Toggle log scale
c	Cycle colormap
i	Toggle info bar

Phase Space (F4)

Key	Action
1–3	Select spatial dimension (x, y, z)
4–6	Select velocity dimension (vx, vy, vz)
+ / - / scroll	Zoom in / out
r / 0	Reset zoom
l	Toggle log scale
c	Cycle colormap / comparison view
p	Toggle physical aspect ratio (default on)
s	Toggle stream-count overlay
i	Toggle info bar

Energy (F5)

Key	Action
t / k / w	Toggle traces: total / kinetic / potential
d	Toggle drift view
1–4	Select panel: energy, mass, Casimir, entropy

Profiles (F7)

Key	Action
1–5	Select profile: density, dispersion, mass, v_circ, anisotropy
l	Toggle log scale
a	Toggle analytic overlay
b	Adjust bin count

Playback keys (when in playback mode)

Key	Action
[ / ]	Step backward / forward one frame
{ / }	Jump 10 frames
Home / End	Jump to start / end
< / >	Decrease / increase playback speed

Config file reference

All sections and fields are optional — sensible defaults are provided. The full config has 10 top-level sections.

[domain] — Simulation domain

Key	Type	Default	Description
spatial_extent	float	10.0	Half-width of the spatial box. Domain spans [-L, L]^3.
velocity_extent	float	5.0	Half-width of the velocity box. Domain spans [-V, V]^3.
spatial_resolution	integer	8	Grid cells per spatial dimension. Must be power-of-2 for FFT solvers.
velocity_resolution	integer	8	Grid cells per velocity dimension. Must be power-of-2 for FFT solvers.
boundary	string	"periodic|truncated"	Spatial BC | velocity BC. Options: periodic, isolated, reflecting | truncated, open
coordinates	string	"cartesian"	Coordinate system
gravitational_constant	float	1.0	Value of G

Memory: N_x^3 * N_v^3 * 8 bytes. A 16^{3 x 16}3 grid = 128 MB. A 32^{3 x 32}3 grid = 8 GB.

[domain]
spatial_extent = 10.0
velocity_extent = 3.0
spatial_resolution = 16
velocity_resolution = 16
boundary = "isolated|truncated"
gravitational_constant = 1.0

---

[model] — Initial conditions

Key	Type	Default	Description
type	string	"plummer"	IC model type
total_mass	float	1.0	Total system mass
scale_radius	float	1.0	Characteristic scale radius

Sub-tables for specific models

[model.king] — Tidally truncated King model

Key	Required	Description
w0	yes	Dimensionless central potential (typical 3.0–9.0)

[model.nfw] — NFW dark matter halo

Key	Required	Description
concentration	yes	c = r_vir / r_s (typical 5–20)
virial_mass	no	Virial mass (default: total_mass)
velocity_anisotropy	no	"isotropic" or beta value

[model.zeldovich] — Zel'dovich pancake

Key	Required	Description
amplitude	yes	Perturbation amplitude (0.1–1.0)
wave_number	yes	Mode wave number

[model.merger] — Two-body merger

Key	Required	Description
separation	yes	Initial separation distance
mass_ratio	yes	m2/m1 (1.0 = equal mass)
relative_velocity	no	Relative velocity (default: 0)
impact_parameter	no	Impact parameter (default: 0)
scale_radius_1	no	Scale radius of body 1
scale_radius_2	no	Scale radius of body 2

[model.tidal] — Tidal stream

Key	Required	Description
progenitor_type	yes	"plummer", "hernquist", "king", "nfw"
progenitor_mass	yes	Progenitor mass
progenitor_scale_radius	yes	Progenitor scale radius
progenitor_position	yes	[x, y, z] position
progenitor_velocity	yes	[vx, vy, vz] velocity
host_type	yes	"point_mass", "nfw_fixed", "logarithmic"
host_mass	yes	Host mass
host_scale_radius	yes	Host scale radius

[model.uniform_perturbation] — Perturbed uniform Maxwellian

Key	Required	Description
background_density	yes	Mean density
velocity_dispersion	yes	Thermal velocity dispersion
perturbation_amplitude	yes	Perturbation amplitude
perturbation_wavenumber	yes	[kx, ky, kz] wave vector

[model.disk] — Exponential disk

Key	Required	Description
disk_mass	no	Disk mass
disk_scale_length	no	Scale length
radial_velocity_dispersion	no	Radial velocity dispersion

[model.custom_file] — Custom 6D array

Key	Required	Description
file_path	yes	Path to .npy file
format	yes	"npy"

---

[solver] — Numerical methods

Key	Type	Default	Description
representation	string	"uniform"	Phase-space representation
poisson	string	"fft_periodic"	Poisson solver
advection	string	"semi_lagrangian"	Advection scheme
integrator	string	"strang"	Time integrator
conservation	string	"none"	Conservation scheme

Phase-space representations

Value	Description	Memory
uniform / uniform_grid	Full 6D grid	O(N^6)
hierarchical_tucker / ht	HT tensor decomposition	O(N3 r3)
tensor_train	Tensor-train decomposition	O(N r^2 d)
sheet_tracker	Lagrangian sheet tracker	O(N^3)
spectral / velocity_ht	Hermite velocity basis	O(N^3 M)
amr	Adaptive mesh refinement	varies
hybrid	Sheet/grid hybrid	varies

Poisson solvers

Value	Description	BC
fft_periodic / fft	FFT periodic	periodic
fft_isolated	Hockney-Eastwood zero-padded FFT (deprecated)	isolated
vgf / vgf_isolated	Vico-Greengard-Ferrando spectral isolated	isolated
tensor / tensor_poisson	Braess-Hackbusch exponential sum	isolated
multigrid	V-cycle multigrid (red-black GS)	isolated
spherical / spherical_harmonics	Legendre decomposition + radial ODE	spherical
tree / barnes_hut	Barnes-Hut octree	isolated

Time integrators

Value	Order	Sub-steps	Description
strang	2nd	3	Strang operator splitting (symplectic)
yoshida	4th	7	Yoshida splitting — best conservation
lie	1st	2	Lie splitting (simplest, least accurate)
unsplit / unsplit_rk4	4th	—	Unsplit method-of-lines RK4
unsplit_rk2	2nd	—	Unsplit RK2
unsplit_rk3	3rd	—	Unsplit RK3
rkei	3rd	3	SSP-RK3 exponential integrator (unsplit)
adaptive / adaptive_strang	2nd	3	Strang with adaptive timestep control
blanes_moan / bm4	4th	—	Blanes-Moan optimized splitting
rkn6	6th	—	6th-order Runge-Kutta-Nyström splitting
bug	varies	—	Basis Update & Galerkin (BUG) for HT tensors
rk_bug / rk_bug3	varies	—	Runge-Kutta BUG variant
parallel_bug / pbug	varies	—	Parallelized BUG
lawson / lawson_rk4	varies	—	Lawson Runge-Kutta exponential integrator

HT/TT solver options [solver.ht]

Key	Type	Default	Description
max_rank	integer	100	Maximum rank per node
initial_rank	integer	16	Initial rank (spectral modes)
tolerance	float	1e-6	HSVD truncation tolerance

[solver]
representation = "uniform"
poisson = "fft_isolated"
advection = "semi_lagrangian"
integrator = "yoshida"
conservation = "none"         # or "lomac" for mass/momentum/energy conservation

---

[time] — Time stepping

Key	Type	Default	Description
t_final	float	10.0	Simulation end time
dt_mode	string	"adaptive"	"adaptive" or "fixed"
dt_fixed	float	0.1	Fixed timestep
cfl_factor	float	0.5	CFL safety factor (0, 1]
dt_min	float	1e-6	Minimum timestep (adaptive)
dt_max	float	1.0	Maximum timestep (adaptive)

---

[output] — Output settings

Key	Type	Default	Description
directory	string	"output"	Base output directory
prefix	string	"run"	Subdirectory prefix
snapshot_interval	float	1.0	Time between snapshot saves
checkpoint_interval	float	10.0	Time between checkpoints
diagnostics_interval	float	0.1	Time between diagnostics rows
format	string	"binary"	Snapshot format

---

[exit] — Termination conditions

The simulation exits when any enabled condition triggers.

Key	Type	Default	Description
energy_drift_tolerance	float	0.5	Max |Delta E / E_0|
mass_drift_tolerance	float	0.1	Max |Delta M / M_0|
virial_equilibrium	bool	false	Exit when virial ratio stabilizes
virial_tolerance	float	0.05	Virial equilibrium tolerance
wall_clock_limit	float	none	Max seconds
cfl_violation	bool	true	Exit on CFL violation
steady_state	bool	false	Exit on steady state
steady_state_tolerance	float	1e-6	Steady state threshold
casimir_drift_tolerance	float	0.0	Max Casimir drift (0 = disabled)
caustic_formation	bool	false	Exit when first caustic forms

---

[performance] — Performance tuning

Key	Type	Default	Description
num_threads	integer	0	Rayon threads (0 = all available)
memory_budget_gb	float	4.0	Memory budget for validation warnings
simd	bool	true	Enable SIMD
allocator	string	"system"	"system", "jemalloc", "mimalloc"

---

[playback] — Playback settings

Key	Type	Default	Description
source_directory	string	none	Snapshot directory path
fps	float	10.0	Playback frames per second
loop_playback	bool	false	Loop at end

---

[logging] — Logging

Key	Type	Default	Description
level	string	"info"	Log level ("trace", "debug", "info", "warn", "error")
file	string	none	Log file path
structured	bool	false	Structured JSON logging

---

[appearance] — TUI appearance

Key	Type	Default	Description
theme	string	"dark"	"dark", "light", "solarized", "gruvbox"
colormap_default	string	"viridis"	"viridis", "inferno", "plasma", "magma", "grayscale", "cubehelix", "coolwarm"
braille_density	bool	true	Braille-based density rendering
border_style	string	"rounded"	"rounded", "plain", "double"
square_pixels	bool	true	Compensate for non-square terminal cells in all heatmaps (F2, F3, F4)
min_columns	integer	80	Minimum terminal width
min_rows	integer	24	Minimum terminal height

Preset configurations

phasma ships with 26 preset TOML configurations in configs/:

Plummer sphere variants

Preset	Grid	Integrator/Solver	Notes
plummer	163 x 163	Strang	Default Plummer starting point
plummer_64	163 x 163	Strang	64-cell spatial grid variant
plummer_128	163 x 163	Strang	128-cell spatial grid variant
plummer_hires	323 x 323	Yoshida	High-resolution (~8 GB)
plummer_yoshida	163 x 163	Yoshida	4th-order integrator comparison
plummer_unsplit	163 x 163	Unsplit RK4	Method-of-lines integrator

Advanced representations

Preset	Model	Solver	Notes
plummer_ht	Plummer	HT tensor	Hierarchical Tucker compressed
plummer_tt	Plummer	TT decomposition	Tensor-train representation
plummer_spectral	Plummer	Spectral velocity	Hermite velocity basis
plummer_lomac	Plummer	LoMaC conservation	Mass/momentum/energy preserving

Alternative Poisson solvers

Preset	Model	Poisson solver	Notes
plummer_tensor_poisson	Plummer	Exp-sum tensor	Braess-Hackbusch isolated
plummer_multigrid	Plummer	V-cycle multigrid	Red-black Gauss-Seidel
plummer_spherical	Plummer	Spherical harmonics	Legendre + radial ODE
nfw_tree	NFW	Barnes-Hut tree	Octree gravity

Other equilibrium models

Preset	Model	Notes
hernquist	Hernquist	Galaxy model
king	King (W0=6)	Tidally truncated equilibrium
nfw	NFW (c=10)	Dark matter halo

Multi-body and cosmological

Preset	Model	Notes
merger_equal	2x Plummer (equal mass)	Head-on collision
merger_unequal	2x Plummer (3:1)	Unequal mass ratio
zeldovich	Zel'dovich	Caustic formation
disk_bar	Exponential disk	Disk stability (Toomre Q)
tidal_point	Tidal Plummer	Point-mass host stream generation
tidal_nfw	Tidal + NFW host	NFW host potential

Stability and testing

Preset	Notes
jeans_unstable	Gravitational instability growth rate
jeans_stable	Stable mode (should not grow)
debug	Minimal 43 x 43 grid for debugging

Sweep config

base_config = "configs/balanced.toml"
output_dir = "output/sweep"

[sweep]
parameters = ["domain.spatial_resolution", "solver.integrator"]

[sweep.values]
"domain.spatial_resolution" = [8, 16, 32]
"solver.integrator" = ["strang", "yoshida"]

Runs a batch simulation for every combination in the Cartesian product. Parameter paths use dot notation matching the config structure.

Convergence config

base_config = "configs/balanced.toml"
output_dir = "output/convergence"

[convergence]
resolutions = [8, 16, 32, 64]
velocity_scale = true
metrics = ["energy_drift", "mass_drift"]

Runs at increasing resolutions and computes convergence rates as log2(error_N / error_2N).

Supported models

Model	Config key	Description
Plummer	plummer	Isotropic sphere with analytic DF, f(E)
Hernquist	hernquist	Galaxy model with closed-form DF
King	king	Tidally truncated (Poisson-Boltzmann ODE + RK4)
NFW	nfw	Dark matter halo (numerical Eddington inversion)
Zel'dovich	zeldovich	Single-mode cosmological pancake
Merger	merger	Two-body superposition of equilibrium ICs
Tidal	tidal	Progenitor in external host potential
Disk	disk_exponential / disk_stability	Exponential disk with Shu DF and Toomre Q
Uniform perturbation	uniform_perturbation	Perturbed Maxwellian (Jeans instability)
Custom file	custom_file	User-provided 6D .npy array

Export formats

Press e to open the export menu:

Key	Format	Description
1	SVG screenshot	Current view as vector graphics
2	CSV time series	Diagnostics history
3	JSON time series	Diagnostics history
4	Parquet time series	Columnar diagnostics
5	TOML config	Current config
6	VTK snapshot	ParaView-compatible density
7	NumPy .npy	Raw density array
8	Markdown report	Full simulation report
9	Frame sequence	Animation frames
0	CSV radial profiles	Radial density/dispersion
a	Parquet performance	Step timing data
z	ZIP archive	Everything: config, diagnostics, snapshots, scripts

Layout modes

phasma adapts to terminal size:

Mode	Size	Behavior
Compact	40x12 – 79x23	Single-panel tabs, abbreviated labels
Normal	80x24 – 159x49	Standard layout
Wide	160x50+	Three-column panels where applicable

Panels below minimum size show a "(too small)" placeholder.

Project structure

phasma/
├── Cargo.toml
├── configs/                    # 26 preset TOML configurations
│   ├── balanced.toml
│   ├── default.toml
│   ├── nfw_high_res.toml
│   ├── ...
│   └── debug.toml
└── src/
    ├── main.rs                 # Entry point, mode dispatch
    ├── sim.rs                  # caustic integration, verbose logging, SimState
    ├── config/
    │   ├── mod.rs              # PhasmaConfig schema (serde, all sections)
    │   ├── defaults.rs         # Memory estimation, smart defaults
    │   ├── presets.rs           # Preset save/load
    │   ├── validate.rs          # Config validation
    │   └── history.rs           # Recent config tracking
    ├── runner/
    │   ├── batch.rs            # Headless batch runner
    │   ├── wizard.rs           # Interactive config wizard
    │   ├── sweep.rs            # Parameter sweep
    │   ├── convergence.rs      # Convergence study
    │   ├── compare.rs          # Batch comparison report
    │   ├── regression.rs       # Regression testing
    │   └── monitor.rs          # Filesystem watcher for --monitor/--tail
    ├── data/
    │   ├── live.rs             # Live data provider (ring buffer, scrub history)
    │   ├── playback.rs         # Playback data provider
    │   └── comparison.rs       # Comparison data provider (A/B/diff)
    ├── tui/
    │   ├── app.rs              # Application state machine, global keybindings
    │   ├── cli.rs              # CLI argument definitions (clap)
    │   ├── tabs/               # 10 tab implementations
    │   ├── widgets/            # Reusable widgets (heatmap, colorbar, sparkline table)
    │   ├── status_bar.rs       # Bottom bar (ETA, throughput, RSS memory, rank)
    │   ├── help.rs             # Help overlay (?-key)
    │   ├── export_menu.rs      # 12-item export format selector
    │   ├── command_palette.rs  # Command palette (:)
    │   ├── layout.rs           # Responsive layout (compact/normal/wide)
    │   └── guard.rs            # Terminal size guard
    ├── export/                 # Export format implementations
    ├── colormaps/              # Terminal colormaps (viridis, inferno, plasma, etc.)
    ├── themes.rs               # Color themes (dark, light, solarized, gruvbox)
    ├── annotations.rs          # Time annotations and bookmarks
    ├── notifications.rs        # Desktop notifications on sim events
    └── session.rs              # Session state persistence

Relationship to caustic

phasma is a consumer of the caustic library. It provides no solver logic — it constructs a caustic::Simulation from user input, runs it on a background thread, and renders live diagnostics.

caustic (lib) <-- depends on <-- phasma (bin)

caustic provides	phasma provides
6D Vlasov-Poisson simulation engine	ratatui TUI with 10 live tabs
8 phase-space representations	TOML config loading with 26 presets
10 Poisson solvers	Real-time density/phase-space heatmaps
14 time integrators	Energy conservation charts and radial profiles
10 IC generators	History scrubbing, playback, comparison
LoMaC conservation framework	Batch mode, sweeps, convergence studies
Diagnostics and exit conditions	Export (CSV, JSON, NPY, Parquet, VTK, ZIP)
rayon parallelism	Verbose logging (--verbose)

To use caustic directly in your own application:

use caustic::*;

let domain = Domain::builder()
    .spatial_extent(10.0)
    .velocity_extent(3.0)
    .spatial_resolution(16)
    .velocity_resolution(16)
    .t_final(10.0)
    .build()?;

let ic = PlummerIC::new(1.0, 1.0, 1.0);
let snap = sample_on_grid(&ic, &domain);

let mut sim = Simulation::builder()
    .domain(domain)
    .poisson_solver(VgfPoisson::new(&domain))
    .advector(SemiLagrangian::new())
    .integrator(YoshidaSplitting::new(1.0))
    .initial_conditions(snap)
    .time_final(10.0)
    .build()?;

while let Ok(None) = sim.step() {
    println!("t={:.4}, E={:.6}", sim.time, sim.diagnostics.history.last().unwrap().total_energy);
}

License

GNU General Public License v3.0. See LICENSE.

Citation

@software{phasma,
  title  = {phasma: Terminal interface for the caustic Vlasov-Poisson solver},
  url    = {https://github.com/resonant-jovian/phasma},
  year   = {2026}
}