topRules {arc}

Rule Generation

Description

A wrapper for the apriori method from the arules package that iteratively changes mining parameters until a desired number of rules is obtained, all options are exhausted or a preset time limit is reached. Within the arc package, this function serves as a replacement for the CBA Rule Generation algorithm (Liu et al, 1998) – without pessimistic pruning – with general apriori implementation provided by existing fast R package arules.

Usage

topRules(
  txns,
  appearance = list(),
  target_rule_count = 1000,
  init_support = 0,
  init_conf = 0.5,
  conf_step = 0.05,
  supp_step = 0.05,
  minlen = 2,
  init_maxlen = 3,
  iteration_timeout = 2,
  total_timeout = 100,
  max_iterations = 30,
  trim = TRUE,
  debug = FALSE
)

Arguments

txns

input transactions.

appearance

object named list or APappearance object (refer to arules package)

target_rule_count

the main stopping criterion, mining stops when the resulting rule set contains this number of rules.

init_support

initial support.

init_conf

initial confidence.

conf_step

confidence will be changed by steps defined by this parameter.

supp_step

support will be changed by steps defined by this parameter.

minlen

minimum length of rules, minlen=1 corresponds to rule with empty antecedent and one item in consequent. In general, rules with empty antecedent are not desirable for the subsequent pruning algorithm, therefore the value of this parameter should be set at least to value 2.

init_maxlen

maximum length of rules, should be equal or higher than minlen. A higher value may decrease the number of iterations to obtain target_rule_count rules, but it also increases the risk of initial combinatorial explosion and subsequent memory crash of the apriori rule learner.

iteration_timeout

maximum number of seconds it should take apriori to obtain rules with current configuration/

total_timeout

maximum number of seconds the mining should take.

max_iterations

maximum number of iterations.

trim

if set to TRUE and more than target_rule_count is discovered, only first target_rule_count rules will be returned.

debug

boolean indicating whether to output debug messages.

Value

Returns an object of class rules.

References

Ma, Bing Liu Wynne Hsu Yiming. Integrating classification and association rule mining. Proceedings of the fourth international conference on knowledge discovery and data mining. 1998.

See Also

prune

Examples

# Example 1
  utils::data(Adult)
  rules <- topRules(Adult, appearance = list(), target_rule_count = 100,
  init_support = 0.5,init_conf = 0.9, minlen = 1, init_maxlen = 10)

# Example 2
  rules <- topRules(as(discrNumeric(datasets::iris, "Species")$Disc.data,"transactions"),
  getAppearance(datasets::iris,"Species"))

# Example 3
  utils::data(datasets::iris)
  appearance <- list(rhs =  c("Species=setosa", "Species=versicolor",
   "Species=virginica"), default="lhs")
  data <- sapply(datasets::iris,as.factor)
  data <- data.frame(data, check.names=FALSE)
  txns <- as(data,"transactions")
  rules <- topRules(txns, appearance)