# integrated_algorithms

## IntegratedAlgorithm Objects

``````class IntegratedAlgorithm(ABC)
``````

Abstract class modeling Memgraph's built-in graph algorithms.

These algorithms are integrated into Memgraph's codebase and are called within a relationship part of a query. For instance: MATCH p = (:City {name: "Paris"}) -[:Road * bfs (r, n | r.length <= 200 AND n.name != "Metz")]-> (:City {name: "Berlin"})

#### __str__

``````@abstractmethod
def __str__() -> str
``````

Instance of IntegratedAlgorithm subclass is used as a string

#### to_cypher_lambda

``````@staticmethod
def to_cypher_lambda(expression: str) -> str
``````

Method for creating a general lambda expression.

Variables `r` and `n` stand for relationship and node. The expression is used e.g. for a filter lambda, to use only relationships of length less than 200: expression="r.length < 200" with the filter lambda being: (r, n | r.length < 200)

Arguments:

• `expression` - Lambda conditions or statements.

``````class BreadthFirstSearch(IntegratedAlgorithm)
``````

Build a BFS call for a Cypher query.

The Breadth-first search can be called in Memgraph with Cypher queries such as: `MATCH (a {id: 723})-[*BFS ..10 (r, n | r.x &gt; 12 AND n.y &lt; 3)]-() RETURN *;` It is called inside the relationship clause, `*BFS` naming the algorithm, `..10` specifying depth bounds, and `(r, n | &lt;expression&gt;)` is a filter lambda.

#### __init__

``````def __init__(lower_bound: int = None,
upper_bound: int = None,
condition: str = None) -> None
``````

Arguments:

• `lower_bound` - Lower bound for path depth.
• `upper_bound` - Upper bound for path depth.
• `condition` - Filter through nodes and relationships that pass this condition.

#### __str__

``````def __str__() -> str
``````

Get a Cypher query string for this algorithm.

#### to_cypher_bounds

``````def to_cypher_bounds() -> str
``````

If bounds are specified, returns them in grammar-defined form.

## DepthFirstSearch Objects

``````class DepthFirstSearch(IntegratedAlgorithm)
``````

Build a DFS call for a Cypher query. The Depth-First Search can be called in Memgraph with Cypher queries such as: MATCH (a {id: 723})-[ ..10 (r, n | r.x > 12 AND n.y < 3)]-() RETURN ; It is called inside the relationship clause, "" naming the algorithm ("" without "DFS" because it is defined like such in openCypher), "..10" specifying depth bounds, and "(r, n | <expression>)" is a filter lambda.

#### __init__

``````def __init__(lower_bound: int = None,
upper_bound: int = None,
condition: str = None) -> None
``````

Arguments:

• `lower_bound` - Lower bound for path depth.
• `upper_bound` - Upper bound for path depth.
• `condition` - Filter through nodes and relationships that pass this condition.

#### __str__

``````def __str__() -> str
``````

get Cypher query string for this algorithm.

#### to_cypher_bounds

``````def to_cypher_bounds() -> str
``````

If bounds are specified, returns them in grammar-defined form.

## WeightedShortestPath Objects

``````class WeightedShortestPath(IntegratedAlgorithm)
``````

Build a Dijkstra shortest path call for a Cypher query.

The weighted shortest path algorithm can be called in Memgraph with Cypher queries such as: " MATCH (a {id: 723})-[r WSHORTEST 10 (r, n | r.weight) weight_sum (r, n | r.x > 12 AND r.y < 3)]-(b {id: 882}) RETURN * " It is called inside the relationship clause, "WSHORTEST" naming the algorithm, "10" specifying search depth bounds, and "(r, n | <expression>)" is a filter lambda, used to filter which relationships and nodes to use.

#### __init__

``````def __init__(upper_bound: int = None,
condition: str = None,
total_weight_var: str = DEFAULT_TOTAL_WEIGHT,
weight_property: str = DEFAULT_WEIGHT_PROPERTY) -> None
``````

Arguments:

• `upper_bound` - Upper bound for path depth.
• `condition` - Filter through nodes and relationships that pass this condition.
• `total_weight_var` - Variable defined as the sum of all weights on path being returned.
• `weight_property` - property being used as weight.

## AllShortestPath Objects

``````class AllShortestPath(IntegratedAlgorithm)
``````

Build a Dijkstra shortest path call for a Cypher query.

The weighted shortest path algorithm can be called in Memgraph with Cypher queries such as: " MATCH (a {id: 723})-[r ALLSHORTEST 10 (r, n | r.weight) total_weight (r, n | r.x > 12 AND r.y < 3)]-(b {id: 882}) RETURN * " It is called inside the relationship clause, "ALLSHORTEST" naming the algorithm, "10" specifying search depth bounds, and "(r, n | <expression>)" is a filter lambda, used to filter which relationships and nodes to use.

#### __init__

``````def __init__(upper_bound: int = None,
condition: str = None,
total_weight_var: str = DEFAULT_TOTAL_WEIGHT,
weight_property: str = DEFAULT_WEIGHT_PROPERTY) -> None
``````

Arguments:

• `upper_bound` - Upper bound for path depth.
• `condition` - Filter through nodes and relationships that pass this condition.
• `total_weight_var` - Variable defined as the sum of all weights on path being returned.
• `weight_property` - Property being used as weight.