# Curve Fitting

 EXPFIT Fit y(x) = A eBx using linearization GAUSSFIT Fit y(x) = A e-B(x-C)2 using linearization IGRID Interpolate XYZ data to regular grid using the Inverse Distance Method INTERP2 Perform two-dimensional linear interpolation INTERPOLATE Linear interpolation of a series. LFIT Fit a line to a series using the end points LINFIT Least squares method of fitting an arbitrary set of basis functions to a series. LINREG Fit a line to series LINREG2 Regress two series LSINFIT Least squares method of fitting sine curves of known frequency PFIT Least squares polynomial fitting with error statistics POLYFIT Return polynomial coefficients POLYGRAPH Graph polynomial fit POWFIT Fit y(x) = A xb using linearization SINFIT Fit y(x) = A + B sin(Cx + D) using the FFT SINFIT3 Fit y(x) = A cos(2πfx + B) + C using least squares SINFIT4 Fit y(x) = A cos(2πfx + B) + C using iterative least squares SINTREND Fit y(x) = A + Bx + C sin(Dx + E) using the FFT SPLINE Cubic spline interpretation SPLINE2 Perform two-dimensional cubic spline interpolation