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Arrays
An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the sums of their horizontal segments form a succession of twelve-tone aggregates * Array mbira, a musical instrument * Spiral array model, a music pitch space Science Astronomy A telescope array, also called astronomical interferometer. Biology * Various kinds of multiple biological arrays called microarrays * Visual feature array, a model for the visual cortex Computer science Generally, a collection of same type data items that can be selected by indices computed at run-time, including: * Array data structure, an arrangement of items at equally spaced addresses in computer memory * Array data type, used in a programming language to specify a variable that can be indexed * Associative array, an abstract data structure model com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Array Data Structure
In computer science, an array is a data structure consisting of a collection of ''elements'' (values or variables), each identified by at least one ''array index'' or ''key''. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula. The simplest type of data structure is a linear array, also called one-dimensional array. For example, an array of ten 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as ten words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index ''i'' has the address 2000 + (''i'' × 4). The memory address of the first element of an array is called first address, foundation address, or base address. Because the mathematical concept of a matrix can be represented as a two-dimensional grid, two-dimensional arrays are also sometimes called "matrices". In some cases the term "vector" is used in comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gate Array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according to a custom order by adding metal interconnect layers in the factory. It was popular during upheaval in semiconductor industry in 80s and its usage declined by end of 90s. Similar technologies have also been employed to design and manufacture analog, analog-digital, and structured arrays, but, in general, these are not called gate arrays. Gate arrays have also been known as ''uncommitted logic arrays'' (''ULAs''), which also offered linear circuit functions, and ''semi-custom chips''. History Development Gate arrays had several concurrent development paths. Ferranti in the UK pioneered commercializing bipolar ULA technology, offering circuits of "100 to 10,000 gates and above" by 1983. The company's early lead in semi-custom chips, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Costas Array
In mathematics, a Costas array can be regarded geometrically as a set of ''n'' points, each at the center of a square in an ''n''×''n'' square tiling such that each row or column contains only one point, and all of the ''n''(''n'' − 1)/2 displacement vectors between each pair of dots are distinct. This results in an ideal "thumbtack" auto- ambiguity function, making the arrays useful in applications such as sonar and radar. Costas arrays can be regarded as two-dimensional cousins of the one-dimensional Golomb ruler construction, and, as well as being of mathematical interest, have similar applications in experimental design and phased array radar engineering. Costas arrays are named after John P. Costas, who first wrote about them in a 1965 technical report. Independently, Edgar Gilbert also wrote about them in the same year, publishing what is now known as the logarithmic Welch method of constructing Costas arrays. Numerical representation A Costas array m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Array
In computer science, a dynamic array, growable array, resizable array, dynamic table, mutable array, or array list is a random access, variable-size list data structure that allows elements to be added or removed. It is supplied with standard libraries in many modern mainstream programming languages. Dynamic arrays overcome a limit of static array data type, arrays, which have a fixed capacity that needs to be specified at Memory management, allocation. A dynamic array is not the same thing as a dynamic memory allocation, dynamically allocated array or variable-length array, either of which is an array whose size is fixed when the array is allocated, although a dynamic array may use such a fixed-size array as a back end.See, for example, thsource code of java.util.ArrayList class from OpenJDK 6 Bounded-size dynamic arrays and capacity A simple dynamic array can be constructed by allocating an array of fixed-size, typically larger than the number of elements immediately require ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Arrays
Global Arrays, or GA, is the library developed by scientists at Pacific Northwest National Laboratory for parallel computing. GA provides a friendly API for shared-memory programming on distributed-memory computers for multidimensional arrays. The GA library is a predecessor to the GAS ( global address space) languages currently being developed for high-performance computing. The GA toolkit has additional libraries including a Memory Allocator (MA), Aggregate Remote Memory Copy Interface (ARMCI), and functionality for out-of-core storage of arrays (ChemIO). Although GA was initially developed to run with TCGMSG, a message passing library that came before the MPI standard ( Message Passing Interface), it is now fully compatible with MPI. GA includes simple matrix computations (matrix-matrix multiplication, LU solve) and works with ScaLAPACK. Sparse matrices are available but the implementation is not optimal yet. GA was developed by Jarek Nieplocha, Robert Harrison, R. J. Litt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Array Slicing
In computer programming, array slicing is an operation that extracts a subset of elements from an array and packages them as another array, possibly in a different dimension from the original. Common examples of array slicing are extracting a substring from a string of characters, the "''ell''" in "h''ell''o", extracting a row or column from a two-dimensional array, or extracting a vector from a matrix. Depending on the programming language, an array slice can be made out of non-consecutive elements. Also depending on the language, the elements of the new array may be aliased to (i.e., share memory with) those of the original array. Details For "one-dimensional" (single-indexed) arrays vectors, sequence, strings etc. the most common slicing operation is extraction of zero or more consecutive elements. Thus, if we have a vector containing elements (2, 5, 7, 3, 8, 6, 4, 1), and we want to create an array slice from the 3rd to the 6th items, we get (7, 3, 8, 6). In programming l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jagged Array
In computer science, a jagged array, also known as a ragged array, irregular array is an array of arrays of which the member arrays can be of different lengths, producing rows of jagged edges when visualized as output. In contrast, two-dimensional arrays are always rectangular so jagged arrays should not be confused with multidimensional arrays, but the former is often used to emulate the latter. Arrays of arrays in languages such as Java, PHP, Python (multidimensional lists), Ruby, C#.NET, Visual Basic.NET, Perl, JavaScript, Objective-C, Swift, and Atlas Autocode are implemented as Iliffe vectors. Examples In C# and Java jagged arrays can be created with the following code: int[][]c; c = new int[2][]; // creates 2 rows c = new int // 5 columns for row 0 c = new int[3]; // create 3 columns for row 1 In C (programming language), C and C++, a jagged array can be created (on the stack) using the following code: int jagged_row0[] = ; int jagged_row1[] = ; int *jagged[] = ; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable-length Array
In computer programming, a variable-length array (VLA), also called variable-sized or runtime-sized, is an array data structure whose length is determined at run time (instead of at compile time). In C, the VLA is said to have a variably modified type that depends on a value (see Dependent type). The main purpose of VLAs is to simplify programming of numerical algorithms. Programming languages that support VLAs include Ada (programming language), Ada, Algol 68 (for non-flexible rows), APL (programming language), APL, C99 (although subsequently relegated in C11 (C standard revision), C11 to a conditional feature, which implementations are not required to support; on some platforms, VLAs could be implemented previously with alloca() or similar functions) and C Sharp (programming language), C# (as unsafe-mode stack-allocated arrays), COBOL, Fortran, Fortran 90, J (programming language), J, and Object Pascal (the language used in Borland Delphi and Lazarus (software), Lazarus, that uses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Array Data Type
In computer science, array is a data type that represents a collection of ''elements'' (value (computer science), values or variable (computer science), variables), each selected by one or more indices (identifying keys) that can be computed at Run time (program lifecycle phase), run time during program execution. Such a collection is usually called an array variable or array value.Robert W. Sebesta (2001) ''Concepts of Programming Languages''. Addison-Wesley. 4th edition (1998), 5th edition (2001), By analogy with the mathematical concepts vector (mathematics), vector and matrix (mathematics), matrix, array types with one and two indices are often called vector type and matrix type, respectively. More generally, a multidimensional array type can be called a tensor type, by anology with the physical concept, tensor. Language support for array types may include certain built-in type, built-in array data types, some syntactic constructions (''array type constructors'') that the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associative Array
In computer science, an associative array, map, symbol table, or dictionary is an abstract data type that stores a collection of (key, value) pairs, such that each possible key appears at most once in the collection. In mathematical terms an associative array is a function with ''finite'' domain. It supports 'lookup', 'remove', and 'insert' operations. The dictionary problem is the classic problem of designing efficient data structures that implement associative arrays. The two major solutions to the dictionary problem are hash tables and search trees..Dietzfelbinger, M., Karlin, A., Mehlhorn, K., Meyer auf der Heide, F., Rohnert, H., and Tarjan, R. E. 1994"Dynamic Perfect Hashing: Upper and Lower Bounds". SIAM J. Comput. 23, 4 (Aug. 1994), 738-761. http://portal.acm.org/citation.cfm?id=182370 In some cases it is also possible to solve the problem using directly addressed arrays, binary search trees, or other more specialized structures. Many programming languages include ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Array
A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache memory and advanced functionality, like RAID, deduplication, encryption and virtualization. Components of a disk array include: * Disk array controllers * Cache in form of both volatile random-access memory and non-volatile flash memory. * Disk enclosures for both magnetic rotational hard disk drives and electronic solid-state drives. * Power supplies Typically a disk array provides increased availability, resiliency, and maintainability by using additional redundant components (controllers, power supplies, fans, etc.), often up to the point where all single points of failure (SPOFs) are eliminated from the design. Additionally, disk array components are often hot-swappable. Traditionally disk arrays were divided into categories: * Network attached storage (NAS) arrays * Storage area network (SAN) arrays: ** Modular SAN arrays ** Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallel Array
In computing, a group of parallel arrays (also known as structure of arrays or SoA) is a form of implicit data structure that uses multiple arrays to represent a singular array of records. It keeps a separate, homogeneous data array for each field of the record, each having the same number of elements. Then, objects located at the same index in each array are implicitly the fields of a single record. Pointers from one object to another are replaced by array indices. This contrasts with the normal approach of storing all fields of each record together in memory (also known as array of structures or AoS). For example, one might declare an array of 100 names, each a string, and 100 ages, each an integer, associating each name with the age that has the same index. Examples An example in C using parallel arrays: int ages[] = ; char *names[] = ; int parent[] = ; for (i = 1; i Joe', 'Bob', 'Frank', 'Hans' last_name => Smith','Seger','Sinatra','Schultze' he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
