It provides the cpp function for FIM for the following model:
~exp(b0+ b1 * x1 + b2 * x2 + b3 * x1 * x2)/(1 + exp(b0 + b1 * x1 + b2 * x2 + b3 * x1 * x2)).
FIM_logistic_2pred(x1, x2, w, param)Fisher information matrix.
Vector of design points (for first predictor).
Vector of design points (for second predictor).
Vector of design weight. Its length must be equal to the length of x and sum(w) = 1.
Vector of values for the model parameters c(b0, b1, b2, b3).