= F =
fudge factor n.
[common] A value or parameter that is
varied in an ad hoc way to produce the desired result. The terms
`tolerance' and slop are also used, though these usually
indicate a one-sided leeway, such as a buffer that is made larger
than necessary because one isn't sure exactly how large it needs to
be, and it is better to waste a little space than to lose
completely for not having enough. A fudge factor, on the other
hand, can often be tweaked in more than one direction. A good
example is the `fuzz' typically allowed in floating-point
calculations: two numbers being compared for equality must be
allowed to differ by a small amount; if that amount is too small, a
computation may never terminate, while if it is too large, results
will be needlessly inaccurate. Fudge factors are frequently
adjusted incorrectly by programmers who don't fully understand
their import. See also coefficient of X.
--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.