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Structure of arrays (SoA) is a layout separating elements of a record (or 'struct' in the C programming language) into one parallel array per field. [1] The motivation is easier manipulation with packed SIMD instructions in most instruction set architectures, since a single SIMD register can load homogeneous data, possibly transferred by a wide internal datapath (e.g. 128-bit).
In array languages, operations are generalized to apply to both scalars and arrays. Thus, a+b expresses the sum of two scalars if a and b are scalars, or the sum of two arrays if they are arrays. An array language simplifies programming but possibly at a cost known as the abstraction penalty.
c = a + b In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also ...
Array types are often implemented by array structures; however, in some languages they may be implemented by hash tables, linked lists, search trees, or other data structures. The term is also used, especially in the description of algorithms , to mean associative array or "abstract array", a theoretical computer science model (an abstract data ...
The structure of the C array is well suited to this particular task. However, in early versions of C the bounds of the array must be known fixed values or else explicitly passed to any subroutine that requires them, and dynamically sized arrays of arrays cannot be accessed using double indexing.
Structures may be initialized or assigned to using compound literals. A function may directly return a structure, although this is often not efficient at run-time. Since C99, a structure may also end with a flexible array member. A structure containing a pointer to a structure of its own type is commonly used to build linked data structures:
Arrays themselves can contain other arrays to form arbitrarily deep structures. Nial also provides Records. They are defined as non-homogenous array structure. Functions in Nial are called Operations. From Nial manual: "An operation is a functional object that is given an argument array and returns a result array.
There is no standard implementation of associative arrays in C, but a 3rd-party library, C Hash Table, with BSD license, is available. [1] Another 3rd-party library, uthash, also creates associative arrays from C structures. A structure represents a value, and one of the structure fields serves as the key. [2]