Regression functions
There is a complete list of the functions currently available for non-linear regression.
This button on the graphics page will bring up the Function List Popover:
Poly2: Second-order polynomial.
PolyAB: Second-order polynomial with y-intercept = zero.
Linear: Simple linear function.
Poly3: Third-order polynomial.
Log: Logarithmic equation with baseline A.
Power: Power function with Y intercept = zero.
Exp: Exponential function with Y intercept = B.
Expb: Exponential function with Y intercept = Ao + B.
DoubleExp: Sum of two Exponentials function with Y intercept = A1 + A2.
Michaelis: Used in enzyme kinetics to fit data that follows the Michaelis-Menton hyperbolic function. This function can be used for any hyperbolic function. The y-intercept is zero.
Hill: Used in enzyme kinetics to fit data that follows the Hill equation of cooperativity.The y-intercept is zero.
1stOrdPrd: Kinetics equation for a first-order reaction in which a product is observed. Af is the final value, Ai is the initial value.
1stOrdDecay: Kinetics equation for a first-order reaction in which a reactant disappears. Standard equation for radioactive decay. Ao is the initial amount at t = zero.
2stOrdPrd: Kinetics equation for a second-order reaction in which a product is observed. Ao is the initial amount at t = zero.
2ndOrdDecay: Kinetics equation for a second-order reaction in which a reactant disappears. Ao is the initial amount at t = zero.
Gaussian: The Gaussian or normal distribution function, is a continuous proability distribution. Sometimes known as a Bell curve. The a parameter is the height of the curve, b is the position of the center of the peak and c controls the width of the "bell". The full width at half maximum (FWHM) is 2.35482 * c.
Logistics:A logistic function is a common sigmoid function, often used to model the growth of some population P. The initial stage of growth is approximately exponential; then, as saturation begins, the growth slows, and at maturity, growth stops.
Surge:A surge function is a common function that has a steep rise from zero, passes through a maximum and then undergoes a decay. The maximum occurs at x=1/b.
