approxfun2 {cooltools} | R Documentation |

## Bilinear interpolation function of data on a regular grid

### Description

Generates a fast function f(x,y) that interpolates gridded data, based on the analogous subroutine `approxfun`

in 1D.

### Usage

```
approxfun2(x, y, z, outside = NA)
```

### Arguments

`x` |
n-vector of x-coordinates; must be strictly monotonically increasing, but not necessarily equally spaced |

`y` |
m-vector of y-coordinates; must be strictly monotonically increasing, but not necessarily equally spaced |

`z` |
n-by-m matrix containing the known function values at the (x,y)-coordinates |

`outside` |
value of the approximation function outside the grid (default is NA) |

### Value

Returns a fast and vectorized interpolation function f(x,y)

### Author(s)

Danail Obreschkow

### See Also

### Examples

```
x = seq(3)
y = seq(4)
z = array(c(x+1,x+2,x+3,x+4),c(3,4))
f = approxfun2(x,y,z)
print(f(1.7,2.4))
```

[Package

*cooltools*version 2.4 Index]