wiggles

n. [scientific computation] In solving partial differential equations by
finite difference and similar methods, wiggles are sawtooth
(up-down-up-down) oscillations at the shortest wavelength representable on
the grid. If an algorithm is unstable, this is often the most unstable
waveform, so it grows to dominate the solution. Alternatively, stable
(though inaccurate) wiggles can be generated near a discontinuity by a Gibbs
phenomenon.

