linfun: Linear Function Fitter

In cooltools: Practical Tools for Scientific Computation and Visualisation

Linear Function Fitter

Description

Fits a global linear model y = a + b x and returns a function that predicts y for arbitrary x, similar in spirit to approxfun, but using a single least-squares line instead of piecewise interpolation.

Usage

linfun(x, y, na.rm = FALSE, ...)

Arguments

x	Numeric vector of predictor values.
y	Numeric vector of response values.
na.rm	Logical; if TRUE, remove NA, NaN, and infinite values before fitting (default: FALSE).
...	Additional arguments passed to lm.

Details

This is a convenience wrapper around lm. It returns a callable function analogous to approxfun, but with a single global linear fit:

f(x) = a + b x,

where a and b are the intercept and slope from a least-squares regression of y on x.

Value

A function f(xnew) that evaluates the fitted linear regression at numeric values xnew.

See Also

[stats::lm()], [stats::approxfun()]

Examples

set.seed(1)
x = 1:10
y = 2 + 3 * x + rnorm(10)
f = linfun(x, y)
plot(x,y)
curve(f, col='red', add = TRUE) # show linear fit
points(6.6,f(6.6),col='red') # show predicted y-value at x = 6.6

cooltools documentation built on Sept. 11, 2026, 5:06 p.m.