Search results
Results From The WOW.Com Content Network
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 C++, associative containers are a group of class templates in the standard library of the C++ programming language that implement ordered associative arrays. [1] Being templates , they can be used to store arbitrary elements, such as integers or custom classes.
A packed storage matrix, also known as packed matrix, is a term used in programming for representing an matrix. It is a more compact way than an m-by-n rectangular array by exploiting a special structure of the matrix. Typical examples of matrices that can take advantage of packed storage include:
One use for such "packed" structures is to conserve memory. For example, a structure containing a single byte (such as a char) and a four-byte integer (such as uint32_t) would require three additional bytes of padding. A large array of such structures would use 37.5% less memory if they are packed, although accessing each structure might take ...
The problem does have a variant which is more tractable. Given any positive integer k≥3, the k-set packing problem is a variant of set packing in which each set contains at most k elements. When k=1, the problem is trivial. When k=2, the problem is equivalent to finding a maximum cardinality matching, which can be solved in polynomial time.
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]
A variable of packed array type maps 1:1 onto an integer arithmetic quantity. In the example above, each element of my_pack may be used in expressions as a six-bit integer. The dimensions to the right of the name (32 in this case) are referred to as "unpacked" dimensions. As in Verilog-2001, any number of unpacked dimensions is permitted.
The integers typically represent iterations of a loop nest or elements of an array. isl uses parametric integer programming to obtain an explicit representation in terms of integer divisions. It is used as backend polyhedral library in the GCC Graphite framework [ 4 ] and in the LLVM Polly framework [ 5 ] for loop optimizations .