Calculates the density-independent rate of total egg production \(R_{di}\) (units 1/year) before density dependence, by species.

## Usage

```
getRDI(
params,
n = initialN(params),
n_pp = initialNResource(params),
n_other = initialNOther(params),
t = 0,
...
)
```

## Arguments

- params
A MizerParams object

- n
A matrix of species abundances (species x size).

- n_pp
A vector of the resource abundance by size

- n_other
A list of abundances for other dynamical components of the ecosystem

- t
The time for which to do the calculation (Not used by standard mizer rate functions but useful for extensions with time-dependent parameters.)

- ...
Unused

## Details

This rate is obtained by taking the per capita rate \(E_r(w)\psi(w)\) at
which energy is invested in reproduction, as calculated by `getERepro()`

,
multiplying it by the number of individuals\(N(w)\) and integrating over
all sizes \(w\) and then multiplying by the reproductive efficiency
\(\epsilon\) and dividing by the egg size `w_min`

, and by a factor of two
to account for the two sexes:
$$R_{di} = \frac{\epsilon}{2 w_{min}} \int N(w) E_r(w) \psi(w) \, dw$$

Used by `getRDD()`

to calculate the actual, density dependent rate.
See `setReproduction()`

for more details.

## Your own reproduction function

By default `getRDI()`

calls `mizerRDI()`

. However you can
replace this with your own alternative reproduction function. If
your function is called `"myRDI"`

then you register it in a MizerParams
object `params`

with

Your function will then be called instead of `mizerRDI()`

, with the
same arguments. For an example of an alternative reproduction function
see `constantEggRDI()`

.

## See also

Other rate functions:
`getEGrowth()`

,
`getEReproAndGrowth()`

,
`getERepro()`

,
`getEncounter()`

,
`getFMortGear()`

,
`getFMort()`

,
`getFeedingLevel()`

,
`getMort()`

,
`getPredMort()`

,
`getPredRate()`

,
`getRDD()`

,
`getRates()`

,
`getResourceMort()`

## Examples

```
# \donttest{
params <- NS_params
# Project with constant fishing effort for all gears for 20 time steps
sim <- project(params, t_max = 20, effort = 0.5)
# Get the density-independent reproduction rate at a particular time step
getRDI(params, n = N(sim)[15, , ], n_pp = NResource(sim)[15, ], t = 15)
#> Sprat Sandeel N.pout Herring Dab Whiting
#> 5.041129e+13 1.053968e+15 9.020326e+13 2.024648e+14 2.517323e+12 3.476507e+13
#> Sole Gurnard Plaice Haddock Cod Saithe
#> 9.988220e+12 1.387214e+12 2.839019e+13 2.983237e+13 1.143392e+14 4.340615e+13
# }
```