cosh — Compute hyperbolic cosine element-wise in MATLAB and RunMat.

Y = cosh(X) computes hyperbolic cosine element-wise. MATLAB documents single and double real or complex arrays; RunMat mode additionally admits typed integers, logicals, and characters through explicit compatibility gates.

Syntax

Y = cosh(X)

Inputs

Returns

Errors

How cosh works

• Works on scalars, vectors, matrices, and N-D tensors with MATLAB broadcasting semantics for scalar expansion.
• Single real and complex inputs preserve single output; double inputs preserve double output.
• Typed integers are a RunMat-only extension. All eight real integer classes require exact binary64 representability before evaluation and produce double output; aligned values above flintmax are accepted when their significant bits fit binary64.
• Logical and character inputs are separately gated RunMat-only extensions and produce double output.
• Complex inputs follow the analytic rule cosh(a + bi) = cosh(a)cos(b) + i·sinh(a)sin(b), propagating NaN/Inf components independently.
• Character arrays are converted to their numeric code points prior to evaluation, with double-precision outputs that preserve the input shape.
• Empty arrays return empty results that respect MATLAB’s shape semantics.
• Table, timetable, tall, and distributed container inputs remain general RunMat container/runtime gaps rather than integer-storage gaps.

Does RunMat run cosh on the GPU?

When RunMat Accelerate is active, tensors that already reside on the GPU stay there. Providers implementing the optional unary_cosh hook execute the operation entirely on the device (and fused elementwise kernels can inline cosh alongside other operations). If the owning provider lacks this hook or returns an invalid output handle, RunMat gathers the data to the host, computes the reference result, and immediately uploads the result back to the input handle's owning provider.

GPU memory and residency

You usually do not need to call gpuArray explicitly. The fusion planner keeps tensors on the GPU whenever the active provider exposes the required kernels (such as unary_cosh). Manual gpuArray / gather calls remain available for MATLAB compatibility or when you must control residency before interoperating with external code.

Examples

Hyperbolic cosine of a scalar

y = cosh(2)

Expected output:

y = 3.7622

Applying cosh elementwise to a vector

x = linspace(-2, 2, 5);
y = cosh(x)

Expected output:

y = [3.7622 1.5431 1.0000 1.5431 3.7622]

Evaluating cosh on a matrix

A = [0 0.5; 1.0 1.5];
B = cosh(A)

Expected output:

B = [1.0000 1.1276; 1.5431 2.3524]

Executing cosh on a GPU tensor

G = gpuArray([0.25 0.75; 1.25 1.75]);
result_gpu = cosh(G);
result = gather(result_gpu)

Expected output:

result = [1.0314 1.2947; 1.8884 2.9642]

Working with complex inputs

z = 1 + 2i;
w = cosh(z)

Expected output:

w = -0.6421 + 1.0686i

Hyperbolic cosine for character codes

chars = 'AZ';
codes = cosh(chars)

Expected output:

codes = [8.4744e27 6.1020e38]

Using cosh with coding agents

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

FAQ

Related Math functions

Open-source implementation

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

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

About RunMat

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