Polyinterp: Difference between revisions

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===Purpose===
===Purpose===


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===Examples===
===Examples===


If y is a 5 by 100 matrix, x is a 1 by 100 vector, and xi is a 1 by 91 vector then polyinterp(x,y,xi,11,3,1) gives the 5 by 91 matrix of first-derivative row vectors resulting from an 11-point cubic interpolation to the 91 points in xi.
If y is a 5 by 100 matrix, x is a 1 by 100 vector, and xi is a 1 by 91 vector then:
<pre>polyinterp(x,y,xi,11,3,1)</pre>
gives the 5 by 91 matrix of first-derivative row vectors resulting from an 11-point cubic interpolation to the 91 points in xi.


===See Also===
===See Also===


[[baseline]], [[lamsel]], [[mscorr]], [[savgol]], [[stdfir]]
[[baseline]], [[lamsel]], [[mscorr]], [[savgol]], [[stdfir]]

Revision as of 22:36, 7 October 2008

Purpose

Polynomial interpolation, smoothing, and differentiation.

Synopsis

yi = polyinterp(x,y,xi,width,order,deriv);

Description

Estimates (yi) which is the smoothed values of (y) at the points in the vector (x). (If the points are evenly spaced use the SAVGOL function instead.)

Inputs

  • y = (M by N) matrix. Note that (y) is a matrix of ROW vectors to be smoothed.
  • x = (1 by N) corresponding axis vector at the points at which (y) is given.

Optional Inputs

  • xi = a vector of points to interpolate to.
  • width = specifies the number of points in the filter {default = 15}.
  • order = the order of the polynomial {default = 2}.
  • deriv = the derivative {default = 0}.

Examples

If y is a 5 by 100 matrix, x is a 1 by 100 vector, and xi is a 1 by 91 vector then:

polyinterp(x,y,xi,11,3,1)

gives the 5 by 91 matrix of first-derivative row vectors resulting from an 11-point cubic interpolation to the 91 points in xi.

See Also

baseline, lamsel, mscorr, savgol, stdfir