1# Concept Collection
3This is a collection of random small projects and demos, most of which can be run entirely in the web browser (client side). Many of them are centered around the [numbl project](https://numbl.org).
5## Interactive numerical methods
7Methods from the numerical literature that you can watch run and adjust, computed client side by numbl (MATLAB syntax in the browser).
9- **[hitandrun-interactive](https://github.com/concept-collection/hitandrun-interactive)** · [live](https://concept-collection.github.io/hitandrun-interactive/#figure/sampler) · the hit-and-run MCMC sampler
10- **[walnuts-interactive](https://github.com/concept-collection/walnuts-interactive)** · [live](https://concept-collection.github.io/walnuts-interactive/#figure/sampler) · the WALNUTS sampler, running the paper's own companion MATLAB code
11- **[barycentric-rational](https://github.com/concept-collection/barycentric-rational)** · [live](https://concept-collection.github.io/barycentric-rational/) · Floater-Hormann rational interpolation, pole-free on any nodes; the method is a MATLAB script you edit in the page
13## numbl tooling: Jupyter, embedding, IDEs
15Ways to write, run, and share MATLAB-syntax code in the browser, all client side (plus a Stan variant of the IDE).
17- **[jupyterlite-numbl-kernel](https://github.com/concept-collection/jupyterlite-numbl-kernel)** · [live](https://concept-collection.github.io/jupyterlite-numbl-kernel/) · MATLAB syntax in Jupyter, no kernel server
18- **[numbl-embed-example](https://github.com/concept-collection/numbl-embed-example)** · [live](https://concept-collection.github.io/numbl-embed-example/) · embed numbl in your own page
19- **[numbl-project-example](https://github.com/concept-collection/numbl-project-example)** · [live](https://concept-collection.github.io/numbl-project-example/) · host a numbl project as a static site
20- **[numbl-web-ide](https://github.com/concept-collection/numbl-web-ide)** · [live](https://concept-collection.github.io/numbl-web-ide/) · a VS Code–style IDE for MATLAB syntax
21- **[stan-web-ide](https://github.com/concept-collection/stan-web-ide)** · [live](https://concept-collection.github.io/stan-web-ide/) · the same IDE for Stan
22- **[numbl-figure-viewer](https://github.com/concept-collection/numbl-figure-viewer)** · [live](https://concept-collection.github.io/numbl-figure-viewer/) · open a figure exported from numbl, underlying data included
24## surfacefun & chunkie examples
26[Surfacefun](https://surfacefun.readthedocs.io/en/latest/) (functions and PDEs on surfaces) and [chunkie](https://chunkie.readthedocs.io/en/latest/) (boundary integral equations in 2D) are MATLAB packages; these examples run them in the browser via numbl.
28- **[numbl-surfacefun-intro](https://github.com/concept-collection/numbl-surfacefun-intro)** · [live](https://concept-collection.github.io/numbl-surfacefun-intro/)
29- **[surfacefun-interactive](https://github.com/concept-collection/surfacefun-interactive)** · [live](https://concept-collection.github.io/surfacefun-interactive/)
30- **[mesh-pde-solver](https://github.com/concept-collection/mesh-pde-solver)** · [live](https://concept-collection.github.io/mesh-pde-solver/)
31- **[numbl-chunkie](https://github.com/concept-collection/numbl-chunkie)** · [live](https://concept-collection.github.io/numbl-chunkie/)
33## MRI pulse sequences
35[Pulseq](https://pulseq.github.io/) is an open framework for defining MRI pulse sequences. Here you can write pulseq sequences in MATLAB syntax and run them in the browser via numbl to generate a `.seq` file, upload and interactively explore an existing one, or simulate one on a digital phantom to see the raw k-space it acquires.
37- **[seqlab](https://github.com/concept-collection/seqlab)** · [live](https://concept-collection.github.io/seqlab/)
38- **[mri-scanner](https://github.com/concept-collection/mri-scanner)** · [live](https://concept-collection.github.io/mri-scanner/)
40## Spherical harmonics on the GPU
42Here are spherical harmonic transforms reimplemented from scratch as WebGPU compute shaders, modeled on [SHTNS](https://nschaeff.bitbucket.io/shtns/), together with a live reaction-diffusion solver built on them: Turing patterns forming on a sphere, with diffusion handled implicitly in spectral space where the Laplace-Beltrami operator is diagonal. turing-surface extends the solver from the round sphere to closed surfaces given by spherical-harmonic embeddings, and turing-surface-cache narrows it to a discrete menu of parameter choices whose solutions at a chosen end time are shared between all visitors through a cloud cache.
44- **[shtns-webgpu](https://github.com/concept-collection/shtns-webgpu)** · [live](https://concept-collection.github.io/shtns-webgpu/)
45- **[turing-sphere](https://github.com/concept-collection/turing-sphere)** · [live](https://concept-collection.github.io/turing-sphere/)
46- **[turing-surface](https://github.com/concept-collection/turing-surface)** · [live](https://concept-collection.github.io/turing-surface/)
47- **[turing-surface-cache](https://github.com/concept-collection/turing-surface-cache)** · [live](https://concept-collection.github.io/turing-surface-cache/)
49## Browser compute benchmarks
51How fast the browser can crunch numbers.
53- **[math-webgpu-sandbox](https://github.com/concept-collection/math-webgpu-sandbox)** · [live](https://concept-collection.github.io/math-webgpu-sandbox/) · MATLAB-syntax scripts compiled to fused WebGPU kernels, timed with the script's own `tic`/`toc`; paste the same script into real MATLAB to compare
54- **[matmul-bench](https://github.com/concept-collection/matmul-bench)** · [live](https://concept-collection.github.io/matmul-bench/) · GEMM in plain JavaScript, WebGPU, SIMD and threaded WASM, and a WASM BLAS, with a native reference
56## Lazy reading of remote HDF5 files
58Here's a demo of reading large remote HDF5 files, such as [NWB](https://www.nwb.org/) neurophysiology files, directly in the browser using HTTP range requests, with no full download and no backend. It shows the approach that [neurosift](https://neurosift.app/) uses to browse these files.
60- **[remote-hdf5-lazy-read](https://github.com/concept-collection/remote-hdf5-lazy-read)** · [live](https://concept-collection.github.io/remote-hdf5-lazy-read/)
62## Scientific data compression
64Here are a few projects on compressing scientific data: a step-by-step visualizer for the [Asymmetric Numeral Systems (ANS)](https://ieeexplore.ieee.org/abstract/document/7170048) entropy-coding algorithm, an interactive study of how compressible quantized noisy time series are, a framework for benchmarking compression algorithms on scientific data arrays, and compression benchmarks for electrophysiology recordings.
66- **[ans-visualizer](https://github.com/concept-collection/ans-visualizer)** · [live](https://concept-collection.github.io/ans-visualizer/)
67- **[timeseries-compressibility](https://github.com/concept-collection/timeseries-compressibility)** · [live](https://concept-collection.github.io/timeseries-compressibility/)
68- **[benchcompress](https://github.com/concept-collection/benchcompress)** · [results](https://concept-collection.github.io/benchcompress/) · [paper (WIP)](https://concept-collection.github.io/benchcompress/paper)
69- **[ephys_compression_tests](https://github.com/concept-collection/ephys_compression_tests)** · [results](https://concept-collection.github.io/ephys_compression_tests/)
71## Speech to text in the browser
73Here's a dictation notepad that transcribes as you speak and never sends your audio anywhere: Whisper and Moonshine run locally via [transformers.js](https://github.com/huggingface/transformers.js), on WebGPU where it's available. The transcript accumulates into a document you can edit and copy.
75- **[voicenote](https://github.com/concept-collection/voicenote)** · [live](https://concept-collection.github.io/voicenote/)
77## Other projects
79### Documents
81- **[mdshare](https://github.com/concept-collection/mdshare)**
82 ([live](https://concept-collection.github.io/mdshare/)).
83 A split-pane markdown editor (LaTeX math, highlighted code, mermaid
84 diagrams) where the document is compressed into the URL itself, so sharing
85 is just copying the link; no server, nothing uploaded.
87### Peer-to-peer shared state
89- **[commonroom](https://github.com/concept-collection/commonroom)**
90 ([live](https://concept-collection.github.io/commonroom/)).
91 Serverless group video calls: pick a room name, share the link, and everyone
92 in the room is connected over a full WebRTC mesh (up to 8 people), with
93 room-wide shared settings.
94- **[commonroom-recorder](https://github.com/concept-collection/commonroom-recorder)**
95 ([run with npx](https://concept-collection.github.io/commonroom-recorder/)).
96 Command-line bot that joins a commonroom call as a visible muted participant
97 and records each participant's audio (plus the chat) to files for
98 transcription.
99- **[commoncall](https://github.com/concept-collection/commoncall)**
100 ([live](https://concept-collection.github.io/commoncall/)).
101 Serverless video calls: enter an ID, see who else is on the page, and call
102 them — call setup rides over nostr relays, media flows peer-to-peer via WebRTC.
103- **[hitandrun-commonview](https://github.com/concept-collection/hitandrun-commonview)**
104 ([live](https://concept-collection.github.io/hitandrun-commonview/)).
105 The hit-and-run figure with a single live view shared by all visitors over a
106 WebRTC mesh; one peer runs the sampler via numbl and broadcasts to the rest.
107- **[commonview](https://github.com/concept-collection/commonview)**
108 ([live](https://concept-collection.github.io/commonview/)).
109 A minimal peer-to-peer page where every visitor shares one state (a counter):
110 nostr discovery, a WebRTC mesh, and a central-peer authority. The basis for
111 hitandrun-commonview.
113### Geometry, meshing & PDE solvers
115- **[mesh-studio](https://github.com/concept-collection/mesh-studio)**
116 ([live](https://concept-collection.github.io/mesh-studio/)).
117 Build CAD primitives or import STEP/IGES with
118 [OpenCASCADE.js](https://ocjs.org/), then inspect them in 3D — including each
119 face's true NURBS surface (polynomials on faces), not just its triangulation.
120- **[mesh-converter](https://github.com/concept-collection/mesh-converter)**
121 ([live](https://concept-collection.github.io/mesh-converter/)).
122 Convert meshes between 19 formats (PLY, OBJ, STL, VTK, Gmsh, XDMF, …) with
123 [meshio](https://github.com/nschloe/meshio) running in-browser on Pyodide;
124 inspect meshes in 3D and see what a lossy export would drop.
125- **[qhull-wasm-demo](https://github.com/concept-collection/qhull-wasm-demo)**
126 ([live](https://concept-collection.github.io/qhull-wasm-demo/)).
127 Demos and benchmarks for [qhull-wasm](https://github.com/magland/qhull-wasm),
128 which compiles [Qhull](http://www.qhull.org) to WebAssembly. Includes 2-D
129 Delaunay triangulation, 3-D convex hull, and a Delaunay benchmark with
130 matching scripts for MATLAB, Octave, and numbl.
131- **[numbl-distmesh](https://github.com/concept-collection/numbl-distmesh)**
132 ([live](https://concept-collection.github.io/numbl-distmesh/)).
133 Every example from Persson and Strang's
134 [DistMesh](https://github.com/popersson/DistMesh), meshing 2-D regions and
135 surfaces from signed distance functions.
136- **[abc-step-1000](https://github.com/concept-collection/abc-step-1000)**
137 ([live](https://concept-collection.github.io/abc-step-1000/)).
138 The first 1000 STEP files from the
139 [ABC dataset](https://deep-geometry.github.io/abc-dataset/) of CAD models
140 (Koch et al., CVPR 2019), served gzip-compressed with a JSON manifest for
141 direct download.
143### Neurophysiology data & remote access
145- **[dandiset_000986](https://github.com/concept-collection/dandiset_000986)**
146 ([visualizations](https://concept-collection.github.io/dandiset_000986/)).
147 Reproducible figures and visualizations for
148 [DANDI Dandiset 000986](https://dandiarchive.org/dandiset/000986), a set of
149 mouse auditory cortex recordings.
151### Physics & quantum systems
153- **[mri-spins](https://github.com/concept-collection/mri-spins)**
154 ([live](https://concept-collection.github.io/mri-spins/)).
155 Interactive MRI physics: a 3D sample of spins evolving under the Bloch
156 equations, with RF pulses, gradients, relaxation, a live signal trace, and a
157 spoiled gradient echo sequence with scanner-like gradient sounds.
158- **[acoustic-scattering-2d](https://github.com/concept-collection/acoustic-scattering-2d)**
159 ([live](https://concept-collection.github.io/acoustic-scattering-2d/)).
160 Sound scattering off a room, a disk, slits, or a lens, solved live on the
161 GPU; the solver and the medium are MATLAB you can edit in the page. Drop a
162 microphone anywhere and listen back.
163- **[acoustic-scattering-3d](https://github.com/concept-collection/acoustic-scattering-3d)**
164 ([live](https://concept-collection.github.io/acoustic-scattering-3d/)).
165 The same physics in three dimensions: spheres, a circular aperture, or a
166 random medium, volume-rendered with a clip plane to see inside, microphone
167 included.
168- **[dulcimer](https://github.com/concept-collection/dulcimer)**
169 ([live](https://concept-collection.github.io/dulcimer/)).
170 A plucked string and the box it sounds over, as two coupled wave equations
171 in editable MATLAB compiled to WebGPU. Render a note and listen to it.
172- **[numbl-quantum-optics](https://github.com/concept-collection/numbl-quantum-optics)**
173 ([live](https://concept-collection.github.io/numbl-quantum-optics/)).
174 Runnable scripts accompanying the article "Quantum optics in MATLAB"
175 ([arXiv:2309.14354](https://arxiv.org/abs/2309.14354)), covering quantum
176 states, operators, and dynamics.
177- **[numbl-open-quantum-systems](https://github.com/concept-collection/numbl-open-quantum-systems)**
178 ([live](https://concept-collection.github.io/numbl-open-quantum-systems/)).
179 Code from "Coding closed and open quantum systems in MATLAB"
180 ([arXiv:1911.04906](https://arxiv.org/abs/1911.04906)), including Ising
181 dynamics, cavity-QED phase transitions, and Lindblad and non-Markovian
182 evolution.
184### Image processing
186- **[numbl-image-filter](https://github.com/concept-collection/numbl-image-filter)**
187 ([live](https://concept-collection.github.io/numbl-image-filter/)).
188 Upload an image, write a MATLAB-syntax filter, and run it on the image in the
189 browser.
191### Number theory & visual math
193- **[finite-field-visualizer](https://github.com/concept-collection/finite-field-visualizer)**
194 ([live](https://concept-collection.github.io/finite-field-visualizer/)).
195 Color-coded multiplication tables over finite (prime) fields. Step through the
196 primes to watch the structure change.
197- **[gcd-visualizer](https://github.com/concept-collection/gcd-visualizer)**
198 ([live](https://concept-collection.github.io/gcd-visualizer/)).
199 A heatmap of the greatest common divisor of every pair (i, j), laid out as a
200 color-coded table.
201- **[random-points-in-disk](https://github.com/concept-collection/random-points-in-disk)**
202 ([live](https://concept-collection.github.io/random-points-in-disk/)).
203 How many random points does it take before a disk looks like a disk? Voxel-density
204 heatmaps of uniform random sampling, next to the 1/√μ noise prediction.