Runge’s Phenomenon

November 6th, 2006 by Walt

I was poking around on Wikipedia, when I came across the page for Runge’s phenomenon. Runge found an example of a smooth function such that if you interpolate it by a high-degree polynomial at fixed points over a finite interval, the approximation of the function by the polynomial becomes very bad. In fact, in the limit as the degree of the interpolated polynomial goes to infinity, the maximum difference between the function and interpolated polynomial also goes to infinity. Interpolating with polynomials is harder than it looks.

2 Responses to “Runge’s Phenomenon”

  1. mrnqfqrhrvum Says:

    “…if you interpolate it by a high-degree polynomial at fixed points over a finite interval…”

    You mean equidistant points here, not fixed.

  2. Depth First Search » Blog Archive » Note to Self Says:

    [...] Don’t use high degree polynomials to do interpolation. Link. Via. Share and Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages. [...]

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