Interpolation

Interpolation[{f1,f2,}]
constructs an interpolation of the function values fi, assumed to correspond to x values 1, 2, .

Interpolation[{{x1,f1},{x2,f2},}]
constructs an interpolation of the function values fi corresponding to x values xi.

Interpolation[{{{x1,y1,},f1},{{x2,y2,},f2},}]
constructs an interpolation of multidimensional data.

Interpolation[{{{x1,},f1,df1,},}]
constructs an interpolation that reproduces derivatives as well as function values.

Interpolation[data,x]
find an interpolation of data at the point x.

Details and OptionsDetails and Options

  • Interpolation returns an InterpolatingFunction object, which can be used like any other pure function.
  • The interpolating function returned by Interpolation[data] is set up so as to agree with data at every point explicitly specified in data.
  • The function values fi can be real or complex numbers, or arbitrary symbolic expressions.
  • The fi can be lists or arrays of any dimension.
  • The function arguments xi, yi, etc. must be real numbers.
  • Different elements in the data can have different numbers of derivatives specified.
  • For multidimensional data, the n^(th) derivative can be given as a tensor with a structure corresponding to D[f,{{x,y,},n}].
  • Partial derivatives not specified explicitly can be given as Automatic.
  • Interpolation works by fitting polynomial curves between successive data points.
  • The degree of the polynomial curves is specified by the option InterpolationOrder.
  • The default setting is InterpolationOrder->3.
  • You can do linear interpolation by using the setting InterpolationOrder->1.
  • Interpolation[data] generates an InterpolatingFunction object that returns values with the same precision as those in data.
  • Interpolation allows any derivative to be given as Automatic, in which case it will attempt to fill in the necessary information from other derivatives or function values.
  • Interpolation supports a Method option. Possible settings include "Spline" for spline interpolation and "Hermite" for Hermite interpolation.

ExamplesExamplesopen allclose all

Basic Examples  (2)Basic Examples  (2)

Construct an approximate function that interpolates the data:

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Apply the function to find interpolated values:

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Plot the interpolation function:

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Compare with the original data:

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Find the interpolated value immediately:

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Introduced in 1991
(2.0)
| Updated in 2008
(7.0)