truncated_lognormal_pred_kernel {mizer} | R Documentation |
Truncated lognormal predation kernel
Description
This is like the lognormal_pred_kernel()
but with an imposed maximum
predator/prey mass ratio
Usage
truncated_lognormal_pred_kernel(ppmr, beta, sigma)
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 |
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.
Value
A vector giving the value of the predation kernel at each of the
predator/prey mass ratios in the ppmr
argument.
See Also
Other predation kernel:
box_pred_kernel()
,
lognormal_pred_kernel()
,
power_law_pred_kernel()