Among the most common tools in electrical engineering and
computer science are rectangular grids of numbers known as
matrices. The numbers in a matrix can represent data: The rows,
for instance, could represent temperature, air pressure and
humidity, and the columns could represent different locations
where those three measurements were taken. But matrices can also
represent mathematical equations. If the expressions t + 2p + 3h
and 4t + 5p + 6h described two different mathematical operations
involving temperature, pressure and humidity measurements, they
could be represented as a matrix with two rows, [1 2 3] and [4 5
6]. Multiplying the two matrices together means performing both
mathematical operations on every column of the data matrix and
entering the results in a new matrix. In many time-sensitive
engineering applications, multiplying matrices can give quick
but good approximations of much more complicated calculations.
In a paper published in the July 13 issue of Proceedings of the
National Academy of