Function: _header_conversions
Class: header
Section: conversions
Doc:
 \subsec{Comparison and Boolean operators}\sidx{Boolean operators} The six
 standard \idx{comparison operators} \kbd{<=}, \kbd{<}, \kbd{>=}, \kbd{>},
 \kbd{==}, \kbd{!=} are available in GP. The result is 1 if the comparison is
 true, 0 if it is false. The operator \kbd{==} is quite liberal : for
 instance, the integer 0, a 0 polynomial, and a vector with 0 entries are all
 tested equal.

 The extra operator \kbd{===} tests whether two objects are identical and is
 much stricter than \kbd{==} : objects of different type or length are never
 identical.

 For the purpose of comparison, \typ{STR} objects are compared using
 the standard lexicographic order, and comparing them to objects
 of a different type raises an exception.

 GP accepts \kbd{<>} as a synonym for \kbd{!=}. On the other hand, \kbd{=} is
 definitely \emph{not} a synonym for \kbd{==}: it is the assignment statement.

 The standard boolean operators \kbd{||} (\idx{inclusive or}), \kbd{\&\&}
 (\idx{and})\sidx{or} and \kbd{!} (\idx{not}) are also available.

 \section{Conversions and similar elementary functions or commands}
 \label{se:conversion}

 \noindent
 Many of the conversion functions are rounding or truncating operations. In
 this case, if the argument is a rational function, the result is the
 Euclidean quotient of the numerator by the denominator, and if the argument
 is a vector or a matrix, the operation is done componentwise. This will not
 be restated for every function.
