sind — Compute element-wise sine values for degree-based angles with MATLAB-compatible canonical outputs.
y = sind(x) evaluates sine using degree-based angles instead of radians. It follows MATLAB-compatible handling for canonical multiples so values like 0, 30, 90, 150, and 180 degrees map cleanly to expected exact outputs.
Syntax
Y = sind(X)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
X | Any | Yes | — | Input scalar, array, logical array, complex value, or gpuArray. |
Returns
| Name | Type | Description |
|---|---|---|
Y | Any | Element-wise sine result with degree input semantics. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:sind:InvalidInput | Input cannot be interpreted as supported numeric/logical/complex data. | sind: invalid input |
RunMat:sind:Internal | Internal gather/conversion/allocation flow failed. | sind: internal error |
How sind works
- Operates element-wise on scalars, vectors, matrices, and N-D tensors.
- Integer and logical inputs are promoted to double precision before evaluation.
- Returns exactly 0 at multiples of 180 and exactly ±1 at the odd multiples of 90 (±90 + 360k).
- Returns exactly ±0.5 at angles congruent to ±30 or ±150 modulo 360.
- Complex inputs delegate to the analytic extension of
sinafter scaling bypi/180; exact-value treatment for complex operands is deferred. - Output shape matches the input shape; non-finite inputs propagate as
NaN. - String inputs are unsupported and raise a builtin-scoped error.
Examples
Sine of a canonical degree angle
y = sind(30)Expected output:
y = 0.5Sine of multiples of 180 returns exactly zero
y = sind([0 180 360])Expected output:
y = [0 0 0]Sine of a vector of common angles
angles = [0 30 45 60 90];
y = sind(angles)Expected output:
y = [0 0.5 0.7071 0.8660 1]Using sind with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how sind changes the result.
Run a small sind example, explain the result, then change one input and compare the output.
FAQ
Why does sind(180) return exactly zero?⌄
MATLAB guarantees an exact zero at multiples of 180 to avoid floating-point noise from pi. RunMat reduces the angle modulo 360 and short-circuits the canonical cases before delegating to sin.
Is sind(x) equivalent to sin(x*pi/180)?⌄
Mathematically yes, but the floating-point result differs at canonical angles because pi/180 is not exact in binary floating point. sind returns the exact MATLAB values at multiples of 30, 90, 150, and 180.
Does sind support arrays?⌄
Yes. Scalars, vectors, matrices, and N-D tensors are all handled element-wise; the shape of the input is preserved.
Related Math functions
Trigonometry
acos · acosh · asin · asinh · atan · atan2 · atanh · cos · cosd · cosh · deg2rad · rad2deg · sin · sinh · tan · tand · tanh
Elementwise
abs · angle · complex · conj · double · exp · expm1 · factorial · gamma · hypot · imag · ldivide · log · log10 · log1p · log2 · minus · nextpow2 · plus · pow2 · power · rdivide · real · sign · single · sqrt · times
Reduction
all · any · cummax · cummin · cumprod · cumsum · cumtrapz · diff · gradient · max · mean · median · min · nnz · prod · std · sum · trapz · var
Structure
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how sind is executed, line by line, in Rust.
- View the source for sind 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.
- Start running code in seconds. RunMat runs in the browser, on the desktop, or from the CLI. No license server, no IT ticket.