P = Here are two vectors representing the census years from 1900 to 1990 and the corresponding United States population in millions of people. Generate a coarse sine curve and interpolate over a finer abscissa.Įxample 2. Type help interp1q at the command line for more information.Įxample 1. For interp1q to work properly, x must be a monotonically increasing column vector and Y must be a column vector or matrix with length(X) rows. Note interp1q is quicker than interp1 on non-uniformly spaced data because it does no input checking. Described in table lookup terms, the table is and interp1 looks up the elements of xi in x, and, based upon their locations, returns values yi interpolated within the elements of Y. Interpolation is the same operation as table lookup.

This function is shown below, along with the relationship between vectors x, Y, xi, and yi. It finds values at intermediate points, of a one-dimensional function that underlies the data. The interp1 command interpolates between data points.

Returns the scalar extrapval for out of range values. Uses the specified method to perform extrapolation for out of range values. For all other methods, interp1 performs extrapolation for out of range values. If Y is a matrix, then the interpolation is performed for each column of Y and yi is length(xi)-by- size(Y,2).Īssumes that x = 1:N, where N is the length of Y for vector Y, or size(Y,1) for matrix Y.įor the 'nearest', 'linear', and 'v5cubic' methods, interp1(x,Y,xi,method) returns NaN for any element of xi that is outside the interval spanned by x. The vector x specifies the points at which the data Y is given. Returns vector yi containing elements corresponding to the elements of xi and determined by interpolation within vectors x and Y. One-dimensional data interpolation (table lookup) Interp1 (MATLAB Functions) MATLAB Function Reference

Matlab interp1 c code