# Find phi parameter for the Exponential spatial auto-correlation function

Source:`R/utils.R`

`find_phi.Rd`

Function designed to find the phi parameter such that the
correlation between points within a given distance `d`

is at most a
given value.

## Usage

```
find_phi(
d,
nu,
kappa,
mu2,
family = "matern",
range = c(1e-04, 1000),
cut = 0.05
)
```

## Arguments

- d
maximum distance for spatial dependence equal to

`cut`

.- nu
smoothness parameter associated with the Matern cov. function.

- kappa
one of the smoothness parameters associated with the Generalized Wendland covariance function

- mu2
one of the smoothness parameters associated with the Generalized Wendland covariance function

- family
covariance function family, the options are

`c("matern", "gw", "cs", "spher", "pexp", "gaussian")`

.- range
Minimum and maximum distance to be considered. The default is

`range = c(1e-04, 1000)`

.- cut
desired spatial correlation at a distance

`d`

, the default is`cut = .05`

.