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Sign Function




''For the Trance dance act called Signum, see Signum (Music Group) .

In Mathematics and especially in Computer Science , the sign function is a logical Function which extracts the sign of a Real Number . To avoid confusion with the Sine function, this function is often called the '''signum function'''. The sign function is often represented as '''sgn''' and can be defined thus:

: \sgn x = \left\{ \begin{matrix}
-1 & : & x < 0 \
0 & : & x = 0 \
1 & : & x > 0 \end{matrix} ight.

or using the Iverson Bracket notation:
:\ \sgn x = - < 0 + > 0

Any real number can be expressed as the product of its Absolute Value and its sign function: