What are boundary conditions in computer science?

Answer 1

The term "boundary conditions" is often used when dealing with the designing, testing and proving of algorithms (and implementations of algorithms). Many solutions to problems have a set of ranges of inputs that they can accept. When designing or testing an algorithm, you need to pay attention to the "boundaries" of the input. It's generally impossible to test every possible set of inputs to your algorithm, but you should be able to prove that it works as expected by testing the boundary conditions for each set of possible inputs.

An example of this can be seen in the typical approach used to convert Cartesian coordinates to polar coordinates. Specifically, to figure out the value of theta given Cartesian coordinates (x,y).

This conversion is defined in the piecewise function:

theta := 0 -- if x 0

theta := arcsin(y/r) -- if x >= 0

theta := arcsin(y/r) + pi -- if x < 0

The boundary conditions of this algorithm:

* x 0 * x >= 0 * x < 0