![](../logo.png)
Truncated lognormal predation kernel
Source:R/pred_kernel_funcs.R
truncated_lognormal_pred_kernel.Rd
This is like the lognormal_pred_kernel()
but with an imposed maximum
predator/prey mass ratio
Arguments
- ppmr
A vector of predator/prey size ratios
- beta
The preferred predator/prey size ratio
- sigma
The width parameter of the log-normal kernel
Value
A vector giving the value of the predation kernel at each of the
predator/prey mass ratios in the ppmr
argument.
Details
Writing the predator mass as \(w\) and the prey mass as \(w_p\),
the feeding kernel is given as
$$\phi_i(w, w_p) =
\exp \left[ \frac{-(\ln(w / w_p / \beta_i))^2}{2\sigma_i^2} \right]
$$
if \(w/w_p\) is between 1 and
\(\beta_i\exp(3\sigma_i)\)
and zero otherwise. Here \(\beta_i\) is the preferred predator-prey mass
ratio and \(\sigma_i\) determines the width of the kernel. These two
parameters need to be given in the species parameter dataframe in the columns
beta
and sigma
.
This function is called from setPredKernel()
to set up the
predation kernel slots in a MizerParams object.
See also
Other predation kernel:
box_pred_kernel()
,
lognormal_pred_kernel()
,
power_law_pred_kernel()