break_down {breakDown}

Model Agnostic Experimental Approach to Break Down Plots with Interactions

Description

This function implements decomposition of model predictions with identification of interactions. The complexity of this function is O(2*p) for additive models and O(2*p^2) for interactions. This function works in similar way to step-up and step-down greedy approaximations, the main difference is that in the fisrt step the order of variables is determied. And in the second step the impact is calculated.

Usage

break_down(
  explainer,
  new_observation,
  check_interactions = TRUE,
  keep_distributions = FALSE
)

Arguments

explainer

a model to be explained, preprocessed by function 'DALEX::explain()'.

new_observation

a new observation with columns that corresponds to variables used in the model

check_interactions

the orgin/baseline for the 'breakDown“ plots, where the rectangles start. It may be a number or a character "Intercept". In the latter case the orgin will be set to model intercept.

keep_distributions

if TRUE, then the distribution of partial predictions is stored in addition to the average.

Value

an object of the broken class

Examples

## Not run: 
library("DALEX")
library("breakDown")
library("randomForest")
set.seed(1313)
# example with interaction
# classification for HR data
model <- randomForest(status ~ . , data = HR)
new_observation <- HRTest[1,]
data <- HR[1:1000,]
predict.function <- function(m,x) predict(m,x, type = "prob")[,1]

explainer_rf_fired <- explain(model,
                 data = HR[1:1000,1:5],
                 y = HR$status[1:1000] == "fired",
                 predict_function = function(m,x) predict(m,x, type = "prob")[,1],
                 label = "fired")

bd_rf <- break_down(explainer_rf_fired,
                 new_observation,
                 keep_distributions = TRUE)

bd_rf
plot(bd_rf)
plot(bd_rf, plot_distributions = TRUE)

bd_rf <- break_down(explainer_rf_fired,
                 new_observation,
                 check_interactions = FALSE,
                 keep_distributions = TRUE)

bd_rf
plot(bd_rf)

# example for regression - apartment prices
# here we do not have intreactions
model <- randomForest(m2.price ~ . , data = apartments)
explainer_rf <- explain(model,
         data = apartmentsTest[1:1000,2:6],
         y = apartmentsTest$m2.price[1:1000],
         label = "rf")

bd_rf <- break_down(explainer_rf,
         apartmentsTest[1,],
         check_interactions = FALSE,
         keep_distributions = TRUE)

bd_rf
plot(bd_rf)
plot(bd_rf, plot_distributions = TRUE)

## End(Not run)