Alternatively, on the Apps tab, in the Math, Statistics, and Optimization group of the apps gallery, click Curve Fitter. In the app, select the data variables for the fit. On the Curve Fitter tab, in the Data section, click Select Data. In the Select Fitting Data dialog box, select x as the X data value and p as the Y data value.

2022年7月5日 · A fairly general sigmoid curve can be expressed with four parameters: ymin, ymax, x0, and slope (dy/dx) at x0. The wikipedia article Sigmoid Function has equations for various sigmoid functions. It has a nice plot comparing different functions. The functions in the wikipedia image all have ymin=-1, ymax=+1, x0=0, and slope=1 at x=0.

For instance, how can I define a sigmoid-like function that is bounded by ylim(5000, 20000) and stretches at x = c(10, 15) or x = c(12, 15)? Like: logistic-curve

2015年3月31日 · If all you care about is curve design rather than fully smooth properties, you can design the second order derivative as linear parts. Then one has full control over symmetry, width, height and so on. The step curve becomes a so-called cubic bezier, namely: Second order derivative is piecewise linear; The first order derivative is piecewise ...

2019年7月24日 · How can I calculate the equation of a sigmoid curve that best fits this partial amount of data? I have attached an image further explaining the problem. The partial data I have fits a curve in black, I want to produce an equation for a sigmoid curve (in blue). Any thoughts on the best way to approach this problem? TIA

2017年8月30日 · The sigmoid function is a function with range (0,1) ... Set fixed endpoint of a sigmoid curve while ...

Along with the other suggestions, a Gompertz growth curve would also fit this data. Here's what Wikipedia has to say about it: A Gompertz curve or Gompertz function, named after Benjamin Gompertz, is a sigmoid function. It is a type of mathematical model for a time series, where growth is slowest at the start and end of a time period.

2013年8月5日 · # # INPUT: # * x: a scalar # * Lambda (default 1): a real number > 0; if lambda <=1, then # the sigmoid is convex at the first half of the curve, and # concave at the second half, that is, it has only one # inflexion point; if Lambda >1, it will be concave between 0 and # 1/2 and convex between 1/2 and 1, with 4 inflexion points, # extending to ...

2020年4月12日 · I can't seem to take the derivative of a sigmoid learning curve function consistently. I've tried a few times with different results. Also, at the end I don't even see how to find the roots! The easiest way I've found so far for the derivative is to use the power and chain rule instead of the quotient rule. Starting with: $$\frac{100}{(1+30e ...

2013年10月10日 · The curve is actually a cumulative distribution, and x is some kind of measurements. He is interested to know what are the corresponding values on x when the cumulative function started to become straight and deviate from being straight.