This predation kernel is a power-law, with sigmoidal cut-offs at large and small predator/prey mass ratios.
power_law_pred_kernel( ppmr, kernel_exp, kernel_l_l, kernel_u_l, kernel_l_r, kernel_u_r )
| ppmr | A vector of predator/prey size ratios at which to evaluate the predation kernel. |
|---|---|
| kernel_exp | The exponent of the power law |
| kernel_l_l | The location of the left, rising sigmoid |
| kernel_u_l | The shape of the left, rising sigmoid |
| kernel_l_r | The location of the right, falling sigmoid |
| kernel_u_r | The shape of the right, falling sigmoid |
A vector giving the value of the predation kernel at each of the
predator/prey mass ratios in the ppmr argument.
The return value is calculated as
ppmr^kernel_exp /
(1 + (exp(kernel_l_l) / ppmr)^kernel_u_l) /
(1 + (ppmr / exp(kernel_l_r))^kernel_u_r)
The parameters need to be given as columns in the species parameter dataframe.