NAG’s mathematical and statistical software components underpin thousands of programs and applications spanning the globe in industries as diverse as finance, science, engineering, academia, and research, and contains more than 1,600 tried and tested routines that are both flexible and portable. www.nag.com/numeric/numerical_libraries.asp
The GNU C Library is designed to be a portable and high performance C library. It is also internationalized and has one of the most complete internationalization interfaces known. The GNU C Library is currently maintained by a community of developers. Learn more on the GNU.org Web site at http://www.gnu.org/software/libc/.