PLS_Toolbox Documentation: polyinterp	< pltternf	polypls >

polyinterp

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