wiggles

from Jargon File (4.4.4, 14 Aug 2003)
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.
    
from The Free On-line Dictionary of Computing (8 July 2008)
wiggles

   [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.
    

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