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
)A vector of predator/prey size ratios at which to evaluate the predation kernel.
The exponent of the power law
The location of the left, rising sigmoid
The shape of the left, rising sigmoid
The location of the right, falling sigmoid
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.