FIT 100
© Copyright 1999-2000
University of Washington
Difficult Problems
vThere are a variety
of kinds of problems that computers “cannot” perform
;Some problems could
be solved in principle, but it would take so long and take so many resources
that it is impractical … simulating the positions of the stars in the Milky Way galaxy
over a million years
;Some
problems cannot be solved because the inputs and process determining the
outcome cannot be known … predicting today’s closing price for
Amazon.Com
;Unsolvable
problems cannot be computed … solving them is logically inconsistent …
a philosophically interesting topic
The “halting problem” is a problem not solvable by computer: No program can tell if another program will halt
eventually or loop forever