Degenerate Conic

CMLIB

The National Bureau of Standards (NBS) Core Math Library (CMLIB) is a "collection of high-quality, easily transportable Fortran subroutine sublibraries solving standard problems in many areas of mathematics and statistics". It was written in FORTRAN 77 and is available from a NIST FTP link. The first version (1.0) was released in March 1986, and the last update (3.0) was in 1988. The software is no longer maintained, and I assume one day the link will probably disappear. It was compiled mostly from other externally-available libraries available at the time (including BLAS, EISPACK, FISHPAK, FNLIB, FFTPACK, LINPACK, and QUADPACK) but there are also some original codes. My Bspline-Fortran package is a modernized update and extension of the DTENSBS routines from CMLIB. The core spline interpolation routines (slightly updated) still work great after more than 30 years.

The National Bureau of Standards (NBS) was renamed the National Institute of Standards and Technology (NIST) in August 1988 (a few months after CMLIB was last updated). The nice thing about these old government-produced codes is that they are public domain in the United States. Indeed any software written by a U.S. government employee (but not a government contractor) as part of their official duties is automatically public domain. I generally prefer permissive software licenses, and you can't get more permissive than that.

See also

• CMLIB — my mirror of the source code on GitHub.
• Netlib — a collection of mathematical software, papers, and databases.
• NIST Applied and Computational Mathematics Division Software Products

Conversion Factors

Conversion Factors

• 1 lbm = 0.45359237 kg
• 1 lbf = 4.4482216152605 N
• 1 ft = 0.3048 m
• 1 mile = 1.609344 km
• 1 nmi = 1.852 km
• 1 slug = 1 \(\mathrm{lbf} ~ \mathrm{s}^2 / \mathrm{ft} \approx\) 14.5939029 kg

References

• NIST Special Publication 811: Guide for the use of the International System of Units.
• Metric system cartoons

Fortran Code

module conversion_factors

use, intrinsic :: iso_fortran_env, only: wp => real64 !double precision

implicit none

real(wp),parameter :: one = 1.0_wp

real(wp),parameter :: lbm2kg = 0.45359237_wp     ! exact
real(wp),parameter :: lbf2N = 4.4482216152605_wp !
real(wp),parameter :: ft2m = 0.3048_wp           !
real(wp),parameter :: mile2km = 1.609344_wp      !
real(wp),parameter :: nmi2km = 1.852_wp          !
real(wp),parameter :: slug2kg = lbf2N/ft2m       ! ~ 14.593902937206362

real(wp),parameter :: kg2lbm = one/lbm2kg        ! ~ 2.2046226218487757
real(wp),parameter :: N2lbf = one/lbf2N          ! ~ 0.2248089430997105
real(wp),parameter :: m2ft = one/ft2m            ! ~ 3.280839895013123
real(wp),parameter :: km2mile = one/mile2km      ! ~ 0.621371192237334
real(wp),parameter :: km2nmi = one/nmi2km        ! ~ 0.5399568034557235
real(wp),parameter :: kg2slug = one/slug2kg      ! ~ 0.06852176585679176

end module conversion_factors