Svector

SVector is a statically sized vector type used in Julia’s StaticArrays.jl package. It represents a vector of length N with element type T, where N is encoded in the type and fixed at compile time. SVector is designed for small, repeatedly used vectors and enables stack allocation and aggressive compiler optimization.

Unlike regular Julia vectors, which are dynamically sized and heap-allocated, SVector instances are immutable and typically allocated on the stack or as part of larger stack-allocated structures. This immutability enables inlining and specialization, allowing operations such as addition, dot product, and cross product to run with minimal allocations and predictable performance. The type is a subtype of AbstractVector and supports most standard vector operations.

Creation is commonly done with the macro @SVector or by constructing the type directly as SVector{N, T}(x1, x2, ..., xN). Constructors infer N from the supplied elements and return an appropriate SVector{N, T}. The SVector type is intended for use when the vector size is small and known at compile time, such as in physics simulations, computer graphics, or real-time computations where performance matters.

Limitations include a fixed length, which makes resizing impossible without creating a new vector, and potential code-size growth or memory usage issues for large N due to specialization. For dynamic-sized needs, or when mutability is required, alternatives such as MVector (mutable vectors) or standard Array-based vectors may be more appropriate.