2-15 INTRINSIC FUNCTIONS & OPTIMIZED LIBRARIES
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Having basic operations done in a standard way, makes programs
more readable and portable, Fortran has a compiler-supplied
basic routine library, the intrinsic routines.
The intrinsic routines have the following properties:
1) The routines are generic (polymorphic in C++ terms) with
respect to argument data type - the proper routine is
automatically choosen by the compiler according to the
data type of the arguments.
Except for the various conversion routines, the data type
of the returned value is like that of the arguments, or
in other words non-conversion routines are generic also
with respect to the return value.
Generic routines simplify programming, some of the
programming decisions are delegated to the compiler.
2) The intrinsic routines are implemented by the compiler,
you don't have to link against a special library.
3) The compiler implements the routines in an efficient
way, either by inlining the code into your program
or calling a routine library.
Intrinsic routines may be more efficient then a routine written
in a high Level Language (HLL), e.g. they could be written in
assembly language and hand optimized. Optimizing a routine for
a given computer is best done by the vendor.
Having an optimized basic routine library is good, but why stop
at the most basic operations? Indeed there is a trend to create
standartized and optimized routine libraries that perform many
operations recurring in practice (see the chapter on libraries).
FORTRAN 77 standard intrinsic functions
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The intrinsic functions of Fortran 90
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