cnocco/dependency

This file defines the functional dependencies that are necessary for the evaluation of canonical covers.

Types

Dependency

opaque </>

The type that represents functional dependencies. Due to the long name of the actual term, the abbreviation Dependency is used.

In general, a Dependency has the form of “alpha -> beta”, where alpha and beta are sets of Ints.

The reason for this type being opaque is that an empty set for alpha is illegal.

pub opaque type Dependency

Values

alpha

</>

pub fn alpha(dep: Dependency) -> set.Set(Int)

A getter for the alpha value.

beta

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pub fn beta(dep: Dependency) -> set.Set(Int)

A getter for the beta value.

delete_empty_all

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pub fn delete_empty_all(
  deps: List(Dependency),
) -> List(Dependency)

Algorithm for deleting Dependencys with an empty beta when finding a canonical cover.

You can use this instead of the entire chain of algorithms if you want to only do a part.

left_reduce_all

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pub fn left_reduce_all(
  deps: List(Dependency),
) -> List(Dependency)

Algorithm for the left reduction when finding a canonical cover.

You can use this instead of the entire chain of algorithms if you want to only do a part.

merge_all

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pub fn merge_all(deps: List(Dependency)) -> List(Dependency)

Algorithm for merging Dependencys with the same alpha when finding a canonical cover.

You can use this instead of the entire chain of algorithms if you want to only do a part.

merge_betas

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pub fn merge_betas(betas: List(set.Set(Int))) -> set.Set(Int)

right_reduce_all

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pub fn right_reduce_all(
  deps: List(Dependency),
) -> List(Dependency)

Algorithm for the right reduction when finding a canonical cover.

You can use this instead of the entire chain of algorithms if you want to only do a part.

to_list_tuple

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pub fn to_list_tuple(dep: Dependency) -> #(List(Int), List(Int))

The reverse of try_from_list_tuple.

to_set_tuple

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pub fn to_set_tuple(
  dep: Dependency,
) -> #(set.Set(Int), set.Set(Int))

The reverse of try_from_set_tuple.

to_string

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pub fn to_string(dep: Dependency) -> String

Parses the Dependency to a nice human-readable String.

Examples:

let assert Ok(dep) = try_from_lists([1, 2], [3, 4])
to_string(dep)
// -> "{1, 2} -> {3, 4}"

try_from_list_tuple

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pub fn try_from_list_tuple(
  tuple: #(List(Int), List(Int)),
) -> Result(Dependency, Nil)

The behavior is the exact same as try_from_lists.

try_from_lists

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pub fn try_from_lists(
  alpha: List(Int),
  beta: List(Int),
) -> Result(Dependency, Nil)

Tries to create a Dependency based on the alpha and beta value provided.

Examples:

try_from_lists([1], [2])
// -> Ok(Dependency)

try_from_lists([], [2])
// -> Error(Nil)

try_from_set_tuple

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pub fn try_from_set_tuple(
  tuple: #(set.Set(Int), set.Set(Int)),
) -> Result(Dependency, Nil)

The behavior is the exact same as try_from_sets.

try_from_sets

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pub fn try_from_sets(
  alpha: set.Set(Int),
  beta: set.Set(Int),
) -> Result(Dependency, Nil)

Tries to create a Dependency based on the alpha and beta value provided.

Examples:

try_from_sets(set.from_list([1]), set.from_list([2]))
// -> Ok(Dependency)

try_from_sets(set.from_list([]), set.from_list([2]))
// -> Error(Nil)