aggregate_contact_matrix — aggregate_contact

Aggregate and Rescale a Square Contact Matrix

Usage

aggregate_contact_matrix(mat, age_breaks, population, symmetric = TRUE)

Arguments

mat: A square numeric matrix of contact rates (e.g., 101 x 101 for ages 0–100).
age_breaks: Numeric vector of lower age boundaries for groups (e.g., c(0, 5, 10, ..., Inf)).
population: A data frame with columns time, age (integer, 1-based), and value (population count).
symmetric: Logical; if TRUE, enforces reciprocity between age groups (default: TRUE).

Value

A square numeric matrix of dimension length(age_breaks) - 1, with sum preserved.

Details

Aggregates a square contact matrix to custom age groups using population-weighted means, then rescales the result to preserve the total sum of the original matrix.

The function first computes the mean population per single-year age across time, assigns each age to a group defined by age_breaks, and aggregates the contact matrix using population-weighted averages. It then rescales the aggregated matrix so that the total sum is equal to that of the original matrix. Optionally, it enforces symmetry (reciprocity) using population group weights.