Re: faster Interpolation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg58886] Re: faster Interpolation?*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Fri, 22 Jul 2005 01:58:35 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 7/21/05 at 3:08 AM, astrumia at mail.df.unipi.it (Alessandro Strumia) wrote: >I need to compute a linear interpolation of a single-parameter >function defined on an equally-spaced grid, and I do not need its >derivatives. >The ListInterpolation function of Mathematica can do this and much >more, but it is not fast enough for my purposes: it takes almost >10^-3 Second on my computer, and I need to compute the function in >about 10^9 points. The total running time would be about one month: >too slow! >So I wonder if there is a faster alternative. One simple way to improve speed would be to only interpolate points around the values of interest at the momement. That is the interpolation algorithms used perform a local interpolation to the order specified. For a linear interpolation, this means only the two points on either side of the value of interest. So, by asking Mathematica to interpolate all 10^9 points you are doing far more computation than needed to get the interpolated result for a handful of values. -- To reply via email subtract one hundred and four