Unit Conversion

There are hundreds of units of measurement in common use.[G. Novak, ``Conversion of Units of Measurement'', IEEE Transactions on Software Engineering, vol. 21, no. 8 (August 1995), pp. 651-661.]

Conversion between different units is an important problem:

• Most programming languages do not support or check units.

• Humans have difficulty converting units. (``Police estimated that the bomb contained 22 pounds of explosive.'')

• Use of the wrong units caused a $327 million spacecraft to crash into Mars.

  en.wikipedia.org/wiki/Mars_Climate_Orbiter

• Although unit conversion is actually easy, several complex and costly methods have been published.