explain.default

0th

Percentile

Create Model Explainer

Black-box models may have very different structures. This function creates a unified representation of a model, which can be further processed by functions for explanations.

Usage
explain.default(
  model,
  data = NULL,
  y = NULL,
  predict_function = NULL,
  residual_function = NULL,
  weights = NULL,
  ...,
  label = NULL,
  verbose = TRUE,
  precalculate = TRUE,
  colorize = TRUE,
  model_info = NULL,
  type = NULL
)

explain( model, data = NULL, y = NULL, predict_function = NULL, residual_function = NULL, weights = NULL, ..., label = NULL, verbose = TRUE, precalculate = TRUE, colorize = TRUE, model_info = NULL, type = NULL )

Arguments
model

object - a model to be explained

data

data.frame or matrix - data which will be used to calculate the explanations. If not provided then will be extracted from the model. Data should be passed without target column (this shall be provided as the y argument). NOTE: If target variable is present in the data, some of the functionalities my not work properly.

y

numeric vector with outputs / scores. If provided then it shall have the same size as data

predict_function

function that takes two arguments: model and new data and returns numeric vector with predictions. By default it is yhat.

residual_function

function that takes four arguments: model, data, response vector y and predict function (optionally). It should return a numeric vector with model residuals for given data. If not provided, response residuals (\(y-\hat{y}\)) are calculated. By default it is residual_function_default.

weights

numeric vector with sampling weights. By default it's NULL. If provided then it shall have the same length as data

...

other parameters

label

character - the name of the model. By default it's extracted from the 'class' attribute of the model

verbose

logical. If TRUE (default) then diagnostic messages will be printed

precalculate

logical. If TRUE (default) then predicted_values and residual are calculated when explainer is created. This will happen also if verbose is TRUE. Set both verbose and precalculate to FALSE to omit calculations.

colorize

logical. If TRUE (default) then WARNINGS, ERRORS and NOTES are colorized. Will work only in the R console.

model_info

a named list (package, version, type) containg information about model. If NULL, DALEX will seek for information on it's own.

type

type of a model, either classification or regression. If not specified then type will be extracted from model_info.

Details

Please NOTE, that the model is the only required argument. But some explanations may expect that other arguments will be provided too.

Value

An object of the class explainer.

It's a list with following fields:

  • model the explained model.

  • data the dataset used for training.

  • y response for observations from data.

  • weights sample weights for data. NULL if weights are not specified.

  • y_hat calculated predictions.

  • residuals calculated residuals.

  • predict_function function that may be used for model predictions, shall return a single numerical value for each observation.

  • residual_function function that returns residuals, shall return a single numerical value for each observation.

  • class class/classes of a model.

  • label label of explainer.

  • model_info named list contating basic information about model, like package, version of package and type.

References

Explanatory Model Analysis. Explore, Explain and Examine Predictive Models. https://pbiecek.github.io/ema/

Aliases
  • explain.default
  • explain
Examples
# NOT RUN {
# simple explainer for regression problem
aps_lm_model4 <- lm(m2.price ~., data = apartments)
aps_lm_explainer4 <- explain(aps_lm_model4, data = apartments, label = "model_4v")
aps_lm_explainer4

# various parameters for the explain function
# all defaults
aps_lm <- explain(aps_lm_model4)

# silent execution
aps_lm <- explain(aps_lm_model4, verbose = FALSE)

# user provided predict_function
aps_lm <- explain(aps_lm_model4, data = apartments, label = "model_4v", predict_function = predict)

# set target variable
aps_lm <- explain(aps_lm_model4, data = apartments, label = "model_4v", y = apartments$m2.price)
aps_lm <- explain(aps_lm_model4, data = apartments, label = "model_4v", y = apartments$m2.price,
                                   predict_function = predict)
# set model_info
model_info <- list(package = "stats", ver = "3.6.2", type = "regression")
aps_lm_model4 <- lm(m2.price ~., data = apartments)
aps_lm_explainer4 <- explain(aps_lm_model4, data = apartments, label = "model_4v",
                             model_info = model_info)

# }
# NOT RUN {
# set model_info
model_info <- list(package = "stats", ver = "3.6.2", type = "regression")
aps_lm_model4 <- lm(m2.price ~., data = apartments)
aps_lm_explainer4 <- explain(aps_lm_model4, data = apartments, label = "model_4v",
                             model_info = model_info)

aps_lm_explainer4 <- explain(aps_lm_model4, data = apartments, label = "model_4v",
                             weights = as.numeric(apartments$construction.year > 2000))

# more complex model
library("ranger")
aps_ranger_model4 <- ranger(m2.price ~., data = apartments, num.trees = 50)
aps_ranger_explainer4 <- explain(aps_ranger_model4, data = apartments, label = "model_ranger")
aps_ranger_explainer4
 
# }
# NOT RUN {
# }
Documentation reproduced from package DALEX, version 1.3.0, License: GPL

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