NAG Library

Implementation-specific Details for Users

The Library is available on many different computer systems. For each distinct system, an implementation of the Library is prepared by NAG, e.g., the Linux 64 (Intel® 64 / AMD64), GNU gfortran implementation. The implementation is distributed to sites as a tested compiled library.
An implementation is usually specific to a range of machines/operating systems (e.g., x86–64 architectures); it may also be specific to a particular Fortran compiler, or compiler option (such as for calling convention).
Essentially the same facilities are provided in all implementations of the Library, but, because of differences in arithmetic behaviour and in the compilation system, routines cannot be expected to give identical results on different systems, especially for sensitive numerical problems.
The documentation supports all implementations of the Library, with the help of a few simple conventions, and a small amount of implementation-dependent information, which is published in a separate Users' Note for each implementation (see Section 4.4 in How to Use the NAG Library and its Documentation).
Each implementation of the NAG Library is generally specific to a particular computing environment on which its operation has been tested and verified. In contrast, the NAG Library Manual is appropriate for all implementations of the Library at that Mark.
Any information that applies solely to a specific implementation is provided, together with the software, on the distribution medium. The Users' Note for your implementation is also available on the NAG web site.
© The Numerical Algorithms Group Ltd, Oxford, UK. 2017