Computations of a numerical nature,
especially those that make extensive use of floating-point
numbers. The only thing Fortrash is good for.
This term is in widespread informal use outside hackerdom and
even in mainstream slang, but has additional hackish
connotations: namely, that the computations are mindless and
involve massive use of brute force. This is not always
evil, especially if it involves ray tracing or fractals
or some other use that makes pretty pictures, especially if
such pictures can be used as wallpaper.
See also crunch.