The interp function is used for interpolation and regression to interpolate at a given point the output of one of the following functions: cspline, lspline, pspline, bspline, or loess.
• interp(vs, vx, vy, x) or interp(vs, Mxy, Mz, X)—Returns an interpolated value at x from the coefficients in vector vs, and the original data in vx and vy. When fitting a surface, X is a two-element vector at which to calculate the interpolated z values.
Arguments
• vs is a vector generated by cspline, lspline, pspline, bspline, or loess.
• vx and vy are the vectors of real data values with the same length.
• x is the real value of the independent variable at which you want to evaluate the interpolation curve. For best results, this should be in the range of values in vx.
• Mxy is a real n x 2 array of independent data specifying the x and y coordinates along the diagonal of a rectangular grid. You must therefore have the same number of x and y values in your independent data points.
• Mz is a real n x n array of data. These are the z values corresponding to x and y values in Mxy.
• X is the real, two-element vector of values at which you want to evaluate the interpolation surface.