R/get_ambiguities_matrix.R

In CausalQueries: Make, Update, and Query Binary Causal Models

#' Get ambiguities matrix
#'
#' Return ambiguities matrix if it exists; otherwise calculate
#' it assuming no confounding.The ambiguities matrix maps from causal types
#' into data types.
#'
#' @inheritParams CausalQueries_internal_inherit_params
#'
#' @return A \code{data.frame}. Causal types (rows) corresponding to
#' possible data realizations (columns).

get_ambiguities_matrix <- function(model) {
    is_a_model(model)
    if (!is.null(model$A)) {
      return(model$A)
    }
    return(make_ambiguities_matrix(model))
}

#' Make ambiguities matrix
#'
#' Make ambiguities matrix. The ambiguities matrix maps from
#' causal types into data types.
#'
#' @inheritParams CausalQueries_internal_inherit_params
#' @return A \code{data.frame}. Types (rows) corresponding to possible
#'   data realizations (columns).
#' @keywords internal

make_ambiguities_matrix <- function(model) {

    # 1. Get types as the combination of possible data. e.g.
    # for X->Y: X0Y00, X1Y00, X0Y10, X1Y10...
    types <- get_causal_types(model)
    var_names <- colnames(types)
    type_labels <-
      vapply(seq_len(nrow(types)), function(i) {
        paste0(var_names, types[i,], collapse = "")
      }, character(1))
    # cbind(types, type_labels) # A check

    # 2. Map types to data realizations. This is done in realise_outcomes
    data_realizations <- realise_outcomes(model)
    types$revealed_data <- apply(data_realizations, 1, paste0, collapse = "")

    # 3.  Create and return matrix A
    # max_possible_data <- get_max_possible_data(model)
    full_possible_data <- get_all_data_types(model, possible_data = TRUE)
    data_names <- full_possible_data$event
    fundamental_data <-
      apply(dplyr::select(full_possible_data, -event),
            1,
            paste0,
            collapse = "")

    # 4. Generate A
    A <- vapply(seq_len(nrow(types)), function(i) {
      (types$revealed_data[i] == fundamental_data) * 1
    }, numeric(length(fundamental_data)))
    A <- matrix(A, ncol = length(type_labels))
    colnames(A) <- type_labels
    rownames(A) <- data_names
    return(t(A))
}


#' Set ambiguity matrix
#'
#' Add an ambiguities matrix to a model
#'
#' @inheritParams CausalQueries_internal_inherit_params
#' @return An object of type \code{causal_model} with the
#'   ambiguities matrix attached

set_ambiguities_matrix <- function(model, A = NULL) {
    if(is.null(A)) {
      A <- make_ambiguities_matrix(model)
    }
    model$A <- A
    class(model$A) <- c("ambiguities_matrix")
    return(model)
}