path — Query or replace the active MATLAB search path string.

path reads or updates the path string used for function/script resolution, preserving MATLAB-compatible path-separator and replacement semantics.

Syntax

oldpath = path()
oldpath = path(path1)
oldpath = path(path1, path2)

Inputs

Returns

Errors

How path works

• path() (no inputs) returns the current search path as a character row vector. Each directory is separated by pathsep (; on Windows, : on Linux/macOS). The current working folder (pwd) is implicit and therefore is not included in the string.
• old = path(newPath) replaces the stored path with newPath and returns the previous value so it can be restored later. newPath may be a character row vector, a string scalar, or a 1-by-N double array of character codes. Whitespace at the ends of entries is preserved, matching MATLAB.
• old = path(path1, path2) sets the path to path1 followed by path2. When both inputs are non-empty they are joined with pathsep; empty inputs are ignored so path("", path2) simply applies path2.
• All inputs must be character vectors or string scalars. Single-element string arrays are accepted. Multirow char arrays, multi-element string arrays, numeric arrays that cannot be interpreted as character codes, and other value types raise path: arguments must be character vectors or string scalars.
• Calling path("") clears the stored path while leaving pwd as the highest-priority location, just like MATLAB. The new value is stored in-process and mirrored to the RUNMAT_PATH environment variable, so exist, which, dir, and other filesystem-aware builtins observe the change immediately.

Does RunMat run path on the GPU?

path operates entirely on host-side state. If an argument lives on the GPU, RunMat gathers it back to the CPU before validation. No acceleration provider hooks are required and no GPU kernels are launched.

GPU memory and residency

No. The MATLAB path is a host-only configuration. RunMat automatically gathers any gpuArray text inputs, applies the request on the CPU, and returns the result as a character array. Explicitly creating gpuArray strings provides no benefit.

Examples

Display the current MATLAB search path

p = path();
disp(p)

Expected output:

//runmat/toolbox://runmat/user

Temporarily replace the MATLAB path

old = path("//runmat-addons");
% ... run code that relies on the temporary path ...
path(old);   % Restore the previous path

Expected output:

old =
    '//runmat/toolbox://runmat/user'

Append folders to the end of the search path

extra = "//projects/analysis";
path(path(), extra);
path()

Expected output:

ans =
    '//runmat/toolbox://runmat/user://projects/analysis'

Prepend folders ahead of the existing path

extra = "/opt/runmat/toolbox";
path(extra, path());
path()

Expected output:

ans =
    '/opt/runmat/toolbox://runmat/toolbox://runmat/user'

Combine generated folder lists

tooling = genpath("submodules/tooling");
old = path(tooling, path())

Expected output:

% The directories returned by genpath now appear ahead of the previous path entries.

Using path with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how path changes the result.

FAQ

Related Io functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how path is executed, line by line, in Rust.

• View the source for path in Rust on GitHub
• Learn how the RunMat runtime works
• Found a bug? Open an issue with a minimal reproduction.

About RunMat

RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.

• RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
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