Mixture Response Calculator

Factory method to return a function that predicts the mixture response given the concentrations of the mixture component chemicals. A factory method is used because the uncertainty quantification is based on a bootstrapped collection of feasible parameters, and each set of parameters leads to a different predictor for the mixture effect. Rather than keeping track of lists of parameters, we immediately convert the sampled parameter set to a function (a "calculator") that takes the mixture concentration as input. The list of calculators can be applied to a

Usage

mix_function_generator(
  param_matrix,
  clust_assign,
  get_counts = FALSE,
  scale_CA = FALSE,
  synergy_const = 0
)

Arguments

param_matrix

a simple matrix object with rows corresponding to unique chemicals and columns representing parameters (a, b, c, max_R, d), where a is the sill b is the EC50 c is the slope value max_R is the maximum sill across all chemicals (deprecated) d is the minimum response (deprecated)

clust_assign

a vector with integers defining cluster membership. For 3 chemicals, a clust_assign could be c(1,2,1), meaning chemicals 1 and 3 are clustered together and 2 is by itself. It is assumed that the cluster assignments start from 1 and do not skip integers.

get_counts

boolean flag to return a count of the number of solutions found

scale_CA

boolean flag to apply Concentration Addition assumption of equal sills

synergy_const

a real number used to adjust the mixture prediction for synergistic effects

Value

an instance of the function mix_effect_fun which takes as input the concentration of the component chemicals and outputs a predict response