maximizeInterpolant {edgeR} | R Documentation

## Maximize a function given a table of values by spline interpolation.

### Description

Maximize a function given a table of values by spline interpolation.

### Usage

    maximizeInterpolant(x, y)

### Arguments

`x` | numeric vector of the inputs of the function.
`y` | numeric matrix of function values at the values of `x`. Columns correspond to `x` values and each row corresponds to a different function to be maximized.

### Details

Calculates the cubic spline interpolant for each row the method of Forsythe et al (1977) using the function `fmm_spline` from `splines.c` in the `stats` package). Then calculates the derivatives of the spline segments adjacant to the input with the maximum function value. This allows identification of the maximum of the interpolating spline.

### Value

numeric vector of input values at which the function maximums occur.

### Author(s)

Aaron Lun, improving on earlier code by Gordon Smyth

### References

Forsythe, G. E., Malcolm, M. A. and Moler, C. B. (1977). Computer Methods for Mathematical Computations, Prentice-Hall.

### Examples

    x <- seq(0,1,length=10)
    y <- rnorm(10,1,1)
    maximizeInterpolant(x,y)

[Package edgeR version 3.22.5 Index]