# tcor: Generates Correlated Traits In ecolottery: Coalescent-Based Simulation of Ecological Communities

## Description

Create two random vectors of traits correlated between each other or a vector of traits correlated to an existing one. The linear correlation is defined by the parameter `rho`.

## Usage

 `1` ```tcor(n, rho = 0.5, mar.fun = rnorm, x = NULL, ...) ```

## Arguments

 `n` the integer number of values to be generated. `rho` a numeric parameter defining the linear correlation between the two traits (default is 0.5). It must belong to the interval [-1, 1]. `x` an vector of numeric values. Default is NULL. `mar.fun` a function defining the random generation for the trait distribution. Default is `rnorm`. `...` other arguments for the `mar.fun()` function.

## Details

`rho` parameter is set to 0.5 by default. `x = NULL` by default. Code adapted from: http://stats.stackexchange.com/questions/15011/generate-a-random-variable-with-a-defined-correlation-to-an-existing-variable

## Value

Return a data.frame with two numeric columns, each column defining a trait.

## Author(s)

P. Denelle F. Munoz

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10``` ```# With no predefined trait traits <- tcor(n = 10000, rho = 0.8) plot(traits[, 1], traits[, 2]) cor(traits[, 1], traits[, 2]) # With existing trait existing_trait <- rnorm(10000, 10, 1) traits <- tcor(n = 10000, rho = 0.8, x = existing_trait) plot(traits[, 1], traits[, 2]) cor(traits[, 1], traits[, 2]) ```

### Example output

```[1] 0.795797
[1] 0.8021336
```

ecolottery documentation built on May 2, 2019, 9:34 a.m.