Abstract :
When a good circuit designer lays out a new circuit, he isolates those functions which are more or less self-contained and puts them in separate modules. This not only has the advantages of simplification, flexibility, and easier maintenance, but it also enables the designer to take advantage of whatever off-the-shelf modules he can obtain. A good programmer plans his programs the same way, dividing the operations up into black boxes called subroutines or procedures. What black boxes should he expect to be able to get "off-the-shelf"? This paper deals with the type of numerical calculations an electrical engineer is likely to do, and describes fourteen kinds of computations for which he could expect to find black boxes to do the job. In addition, ten kinds of computations are described for which he should not look for black boxes, as either they do not exist or they are hopelessly inadequate.
