- published: 12 Jan 2015
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In computer science, A* (pronounced "A star" (listen)) is a computer algorithm that is widely used in pathfinding and graph traversal, the process of plotting an efficiently traversable path between points, called nodes. Noted for its performance and accuracy, it enjoys widespread use. Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute (now SRI International) first described the algorithm in 1968. It is an extension of Edsger Dijkstra's 1959 algorithm. A* achieves better performance (with respect to time) by using heuristics.
A* uses a best-first search and finds a least-cost path from a given initial node to one goal node (out of one or more possible goals).
It uses a distance-plus-cost heuristic function (usually denoted Failed to parse (Missing texvc executable; please see math/README to configure.): f(x) ) to determine the order in which the search visits nodes in the tree. The distance-plus-cost heuristic is a sum of two functions:
)
).
The Failed to parse (Missing texvc executable; please see math/README to configure.): h(x)
Patrick Chukwuemeka Okogwu (born 7 November 1988), better known by his stage name Tinie Tempah, is an English rapper. He made his first mixtape in 2007; his first album, Disc-Overy, debuted at number one in October 2010 and was preceded by two number-one singles.
Patrick Chukwuemeka Okogwu, was born in London, England on 7 November 1988, and is of Ibusa, Delta State, Nigerian origin. He lived on the Aylesbury Estate in South East London until he was 12 with his parents and three younger siblings. He attended St. Paul's Catholic School in Abbey Wood, London SE2, (now known as St. Paul's Academy). He went on to study A Levels at St Francis Xavier Sixth Form College, SW12. Of his London upbringing, Tempah states: “London is one of the only places in the world where you can live in a council block and see a beautiful semi-detached house across the street. Growing up around that was inspirational, it kept me motivated".
In 2006, Tempah gained a great deal of airplay on British music TV channel, Channel AKA, for his song "Tears" He made his first mixtape in 2007 with 28 songs, freestyles and remixes, featuring Mz Bratt, Chipmunk and G-Unit.[citation needed] His first album, Disc-Overy, debuted at number one in October 2010 and was preceded by the number-one singles "Pass Out" and "Written in the Stars" and the UK Top 5 hits "Frisky" and "Miami 2 Ibiza". In late 2007, he collaborated on a track ("Perfect GCD Hood Economics Room 147") with grime artist Ultra and producers/songwriters Agent X.
There was a girl who couldn't speak
Who couldn't speak her mind
Only thing she was good at
Was telling stories of faraway lands
There was a guy who couldn't say
Who couldn't say what he wanted
Only thing he was good at
Was cracking jokes to make people laugh
So many words he swallowed
So many thoughts she kept to herself
And when they met they made love
And talked about the world and the weather
So many cities he walked
So many countries she traveled
And in their dreams they would listen