Sort

Sort may refer to:

See also

Sorting algorithm

A sorting algorithm is an algorithm that puts elements of a list in a certain order. The most-used orders are numerical order and lexicographical order. Efficient sorting is important for optimizing the use of other algorithms (such as search and merge algorithms) which require input data to be in sorted lists; it is also often useful for canonicalizing data and for producing human-readable output. More formally, the output must satisfy two conditions:

Further, the data is often taken to be in an array, which allows random access, rather than a list, which only allows sequential access, though often algorithms can be applied with suitable modification to either type of data.

Since the dawn of computing, the sorting problem has attracted a great deal of research, perhaps due to the complexity of solving it efficiently despite its simple, familiar statement. For example, bubble sort was analyzed as early as 1956. Comparison sorting algorithms have a fundamental requirement of O(n log n) comparisons (some input sequences will require a multiple of n log(n) comparisons); algorithms not based on comparisons, such as counting sort, can have better performance. Although many consider sorting a solved problem – asymptotically optimal algorithms have been known since the mid-20th century – useful new algorithms are still being invented, with the now widely used Timsort dating to 2002, and the library sort being first published in 2006.

Structure (mathematical logic)

In universal algebra and in model theory, a structure consists of a set along with a collection of finitary operations, and relations that are defined on it.

Universal algebra studies structures that generalize the algebraic structures such as groups, rings, fields and vector spaces. The term universal algebra is used for structures with no relation symbols.

Model theory has a different scope that encompasses more arbitrary theories, including foundational structures such as models of set theory. From the model-theoretic point of view, structures are the objects used to define the semantics of first-order logic. For a given theory in model theory, a structure is called a model, if it satisfies the defining axioms of that theory, although it is sometimes disambiguated as a semantic model when one discusses the notion in the more general setting of mathematical models. Logicians sometimes refer to structures as interpretations.

In database theory, structures with no functions are studied as models for relational databases, in the form of relational models.

Glimpse

Glimpse may refer to:

GLIMPSE may refer to:

Glimpse: Live Recordings from Around the World

Glimpse: Live Recordings from Around the World is Sonicflood's sixth original album and second live album. It was released on October 31, 2006.

Track listing

Personnel

References

GLIMPSE

GLIMPSE is a text indexing and retrieval software program originally developed at the University of Arizona by Udi Manber, Sun Wu, and Burra Gopal. It was released under the ISC open source license in September 2014.

GLIMPSE stands for GLobal IMPlicit SEarch. While many text indexing schemes create quite large indexes (usually around 50% of the size of the original text), a GLIMPSE-created index is only 2-4% of the size of the original text.

GLIMPSE uses and takes a great deal of inspiration from Agrep, which was also developed at the University of Arizona, but GLIMPSE uses a high level index whereas Agrep parses all the text each time.

The basic algorithm is similar to other text indexing and retrieval engines, except that the text records in the index are huge, consisting of multiple files each. This index is searched using a boolean matching algorithm like most other text indexing and retrieval engines. After one or more of these large text records is matched, Agrep is used to actually scan for the exact text desired. While this is slower than traditional totally indexed approaches, the advantage of the smaller index is seen to be advantageous to the individual user. This approach would not work particularly well across websites, but it would work reasonably well for a single site, or a single workstation. In addition, the smaller index can be created more quickly than a full index.