Tom-Alexander/regression-js

4PL and 5PL curve fit

Zireael opened this issue · 2 comments

Zireael commented

Hi, is it possible to use regressin-js to perform 4PL and 5PL curve fit?
image

R code example for both:
https://weightinginbayesianmodels.github.io/poctcalibration/calib_tut4_curve_background.html
https://rdrr.io/cran/ELISAtools/src/R/Regression.R

Initial parameters (ABCDG) can be set as follows:
5PL or 4PL
where:
A: Minimum asymptote. In a bioassay where you have a standard curve, this can be thought of as the response value at 0 standard concentration. A = Min(y)

B: Hill's slope. The Hill's slope refers to the steepness of the curve. It could either be positive or negative. B = the slope of the line between highest and lowest point, for example Δy/Δx : (1.7914-0.130033)/(25-0.098)

C: Inflection point. The inflection point is defined as the point on the curve where the curvature changes direction or signs. C is the concentration of analyte where C=(D-A)/2

D: Maximum asymptote. In an bioassay where you have a standard curve, this can be thought of as the response value for infinite standard concentration. D = Max(y)

G: Asymmetry factor. When G=1 we have a symmetrical curve around inflection point and so we have a four-parameters logistic equation. G = 1

I've found examples to do the curve fit in R and Python but can't find a clear way to do it in Javascript.

Thanks in advance!