`isgpuarray` — Return true when a value is stored as a gpuArray handle.

tf = isgpuarray(x) returns a logical scalar that is true when x is a gpuArray handle. All other value kinds, including numeric arrays, logical arrays, characters, structs, and objects, return false.

How does the `isgpuarray` function behave in MATLAB / RunMat?

gpuArray values return true without gathering device buffers.
Numeric, logical, complex, string, character, struct, cell, and object inputs return false.
The result is always a logical scalar.

GPU behavior

The builtin only checks whether the value is a gpuArray handle. It never gathers device buffers or inspects the underlying data contents.

GPU residency

RunMat keeps data on the GPU when a provider is active, and isgpuarray lets you verify residency boundaries in MATLAB-style code.

Examples of using `isgpuarray` in MATLAB / RunMat

Checking a gpuArray handle

G = gpuArray(reshape(1:12, [3 4]));
tf = isgpuarray(G)

Expected output:

tf =
     1

Host arrays are not gpuArray values

A = [1 2 3];
tf = isgpuarray(A)

Expected output:

tf =
     0

FAQ

Does `isgpuarray` gather data back to the host?

No. It inspects value metadata and returns a logical scalar without triggering a device transfer.

What happens if no acceleration provider is registered?

isgpuarray still reports accurately for values that are already gpuArray handles. If a value is not a gpuArray handle, it returns false.

Source & Feedback

Source code: `crates/runmat-runtime/src/builtins/logical/tests/isgpuarray.rs`
Found a bug? Open an issue with a minimal reproduction.

isgpuarray — Return true when a value is stored as a gpuArray handle.

How does the isgpuarray function behave in MATLAB / RunMat?