MATLAB Compatibility

RunMat is a high-performance runtime for MATLAB code. It supports ~99% of core MATLAB language syntax, 330+ built-in functions, and full classdef OOP — with automatic GPU acceleration across all major vendors. No license required.

This page summarizes what works, what doesn't, and where to look for details. For the full feature-by-feature matrix, see Language Coverage. For individual functions, see the Built-in Function Reference.

Language coverage

RunMat targets MATLAB's core language grammar and semantics. Engineers familiar with MATLAB can be productive immediately — no new language to learn.

Category	Status	Highlights
Variables & data types	✅	`double`, `single`, char arrays, string arrays, logicals, integers (`int8`…`uint64`), complex numbers, `global`, `persistent`
Operators	✅	Arithmetic, element-wise, relational, logical (element-wise and short-circuit), transpose (`'` and `.'`), colon ranges
Control flow	✅	`if/elseif/else`, `for`, `while`, `switch/case/otherwise`, `break`, `continue`, `return`, `try/catch/end`, `rethrow`
Functions	✅	Named functions, multiple returns (`[a,b]=f()`), anonymous functions with closures, `varargin`/`varargout`, `nargin`/`nargout`
Indexing & slicing	✅	N-D numeric indexing, logical indexing, `end` arithmetic, struct field access, cell content indexing, function/cell expansion into slice targets
OOP (`classdef`)	✅	Properties (including `Dependent`), methods (static/instance), events (`addlistener`/`notify`), handle classes, enumerations, operator overloading, metaclass operator `?Class`
Packages & imports	✅	`import pkg.`, `import pkg.name`, MATLAB-parity precedence (locals > user > specific > wildcard > `Class.`)
Scripting & syntax	✅	`.m` scripts, `%` and `%{ %}` comments, line continuation `...`, semicolon suppression, command-form calls
Exceptions	✅	`MException` with MATLAB-compatible identifiers and messages across indexing, arity, and OOP error paths

Full details: Language Coverage

Built-in functions

RunMat includes 330+ core MATLAB built-in functions covering math, linear algebra, array creation and manipulation, string operations, file I/O, and more. Notable additions include peaks (GPU-accelerated), clear/clc/close all session management, and full mldivide (backslash) linear system solving.

Browse the complete list: Built-in Function Reference

Plotting

RunMat includes 40+ plotting builtins with GPU-first rendering, interactive 3D camera, theming, and scene persistence.

2D chart types: plot, scatter, bar, histogram, hist, area, stairs, stem, errorbar, pie, contour, contourf, image, imagesc, quiver

3D chart types: plot3, surf, surfc, mesh, meshc, scatter3

Log-scale: semilogx, semilogy, loglog

Figure management: figure, subplot, hold, clf, cla, close, title, xlabel, ylabel, zlabel, legend, colorbar, colormap, axis, grid, box, shading, view, drawnow, pause

Handle graphics: get, set

Rendering is GPU-first: vertex buffers are built on-device and rendered through WebGPU in the browser or Metal/Vulkan/DX12 natively. Interactive 3D camera supports rotate, pan, and zoom with reversed-Z depth.

Advanced/specialized chart types (polar, heatmap, geobubble, wordcloud, stackedplot, swarmchart) and full annotation objects are not yet supported.

Toolbox coverage

RunMat focuses on core MATLAB — the language, operators, data types, and general-purpose built-in functions. MATLAB's add-on toolboxes are not included. Engineers whose workflows depend on specific toolboxes should check the table below.

MATLAB Toolbox	RunMat Status	Notes
Core MATLAB	✅	~99% language, 330+ functions, full OOP, GPU
Simulink	❌	RunMat is script-based only; no block-diagram modeling
Signal Processing	❌	Not implemented
Control System	❌	Not implemented
Image Processing	❌	Basic array ops and `image`/`imagesc` work on image data
Statistics & Machine Learning	❌	Core stats functions (`mean`, `std`, `var`, `median`, `sort`, `hist`, etc.) are available as builtins
Optimization	❌	Not implemented
Symbolic Math	❌	Not implemented
Parallel Computing	⚠️	Different model — RunMat provides automatic GPU acceleration without explicit `gpuArray` or `parfor`

Compatibility modes

RunMat supports three compatibility modes, configured in .runmat:

compat = "runmat" (default) — accepts MATLAB command syntax (hold on, axis equal, etc.) with RunMat error namespaces
compat = "matlab" — same as runmat but error identifiers use MATLAB: prefix for closer parity
compat = "strict" — disables command-style implicit forms; all calls must use explicit parenthesized syntax

Details: Language Reference

Where RunMat goes beyond MATLAB

GPU-native tensor execution on any vendor (NVIDIA, AMD, Intel, Apple) via Metal, Vulkan, DirectX 12, and WebGPU — not CUDA-only
Automatic device planning and fusion — the runtime picks CPU vs GPU based on data size and fuses compatible operations into fewer kernels
Zero-temporary slice expansion — function/cell outputs write directly to destination slices without intermediate copies
Memory safety — Rust implementation eliminates entire classes of memory bugs
Browser-native — full IDE runs client-side via WebAssembly with no server, no login, no quotas
Built-in versioning — automatic per-save file history, snapshots, and git export without requiring engineers to learn git

Where RunMat goes beyond GNU Octave

Full classdef OOP (properties, methods, events, handle classes, enumerations, operator overloading, metaclass ?Class)
import pkg.* / import pkg.name with MATLAB-parity precedence
N-D end arithmetic across dimensions in both gather and scatter
Function/cell expansion into slice targets with dynamic packing
Uniform MException identifier/message model
Automatic GPU acceleration (Octave has no GPU support)
String arrays ("...") with MATLAB-parity indexing and comparison

Known limitations

No Simulink — RunMat is a script/function runtime, not a block-diagram simulation environment
No GUI frameworks — GUIDE and App Designer are not supported
No MATLAB toolboxes — Signal Processing, Control System, Image Processing, etc. are not included (see table above)
Plotting gaps — specialized chart types (polar, heatmap, etc.) and full Handle Graphics property coverage are still being added
File I/O — core functions (load, save, fopen, fclose, fprintf, fscanf, fread, fwrite, readmatrix, writematrix) are available; some advanced I/O functions are not yet implemented
MEX / Java / Python interop — not supported

Performance

RunMat uses a tiered execution model inspired by Google's V8: code starts running immediately in an interpreter, then hot paths are compiled into optimized machine code.

Monte Carlo (5M paths): ~2.8x faster than PyTorch, ~130x faster than NumPy
Elementwise chains (1B elements): ~100x+ faster than PyTorch when fusion eliminates memory traffic
Startup: ~5 ms via snapshot-based initialization

Full benchmark data: Benchmarks

Will my MATLAB code run in RunMat?

The fastest way to find out:

Open the browser sandbox
Paste your .m script
Hit Run — no install, no account, no upload

Your code stays local. Nothing is sent to a server.

If something doesn't work, open an issue with a minimal reproducer and we'll add a conformance test.