/solve/graph

URL: https://<aws.fqdn>/<aws.cluster.name>/gpudb-0/solve/graph

Solves an existing graph for a type of problem (e.g., shortest path, page rank, travelling salesman, etc.) using source nodes, destination nodes, and additional, optional weights and restrictions.

IMPORTANT: It's highly recommended that you review the Graphs & Solvers concepts documentation, the Graph REST Tutorial, and/or some /solve/graph examples before using this endpoint.

Input Parameter Description

Name

Type

Description

graph_name

string

Name of the graph resource to solve.

weights_on_edges

array of strings

Additional weights to apply to the edges of an existing graph. Weights must be specified using identifiers; identifiers are grouped as combinations. Identifiers can be used with existing column names, e.g., 'table.column AS WEIGHTS_EDGE_ID', expressions, e.g., 'ST_LENGTH(wkt) AS WEIGHTS_VALUESPECIFIED', or constant values, e.g., '{4, 15, 2} AS WEIGHTS_VALUESPECIFIED'. Any provided weights will be added (in the case of 'WEIGHTS_VALUESPECIFIED') to or multiplied with (in the case of 'WEIGHTS_FACTORSPECIFIED') the existing weight(s). If using constant values in an identifier combination, the number of values specified must match across the combination. The default value is an empty array ( [] ).

restrictions

array of strings

Additional restrictions to apply to the nodes/edges of an existing graph. Restrictions must be specified using identifiers; identifiers are grouped as combinations. Identifiers can be used with existing column names, e.g., 'table.column AS RESTRICTIONS_EDGE_ID', expressions, e.g., 'column/2 AS RESTRICTIONS_VALUECOMPARED', or constant values, e.g., '{0, 0, 0, 1} AS RESTRICTIONS_ONOFFCOMPARED'. If using constant values in an identifier combination, the number of values specified must match across the combination. If remove_previous_restrictions option is set to true, any provided restrictions will replace the existing restrictions. Otherwise, any provided restrictions will be added (in the case of 'RESTRICTIONS_VALUECOMPARED') to or replaced (in the case of 'RESTRICTIONS_ONOFFCOMPARED'). The default value is an empty array ( [] ).

solver_type

string

The type of solver to use for the graph. The default value is SHORTEST_PATH.

Supported Values	Description
SHORTEST_PATH	Solves for the optimal (shortest) path based on weights and restrictions from one source to destinations nodes. Also known as the Dijkstra solver.
PAGE_RANK	Solves for the probability of each destination node being visited based on the links of the graph topology. Weights are not required to use this solver.
PROBABILITY_RANK	Solves for the transitional probability (Hidden Markov) for each node based on the weights (probability assigned over given edges).
CENTRALITY	Solves for the degree of a node to depict how many pairs of individuals that would have to go through the node to reach one another in the minimum number of hops. Also known as betweenness.
MULTIPLE_ROUTING	Solves for finding the minimum cost cumulative path for a round-trip starting from the given source and visiting each given destination node once then returning to the source. Also known as the travelling salesman problem.
INVERSE_SHORTEST_PATH	Solves for finding the optimal path cost for each destination node to route to the source node. Also known as inverse Dijkstra or the service man routing problem.
BACKHAUL_ROUTING	Solves for optimal routes that connect remote asset nodes to the fixed (backbone) asset nodes.
ALLPATHS	Solves for paths that would give costs between max and min solution radia - Make sure to limit by the 'max_solution_targets' option. Min cost shoudl be >= shortest_path cost.
STATS_ALL	Solves for graph statistics such as graph diameter, longest pairs, vertex valences, topology numbers, average and max cluster sizes, etc.
CLOSENESS	Solves for the centrality closeness score per node as the sum of the inverse shortest path costs to all nodes in the graph.

source_nodes

array of strings

It can be one of the nodal identifiers - e.g: 'NODE_WKTPOINT' for source nodes. For BACKHAUL_ROUTING, this list depicts the fixed assets. The default value is an empty array ( [] ).

destination_nodes

array of strings

It can be one of the nodal identifiers - e.g: 'NODE_WKTPOINT' for destination (target) nodes. For BACKHAUL_ROUTING, this list depicts the remote assets. The default value is an empty array ( [] ).

solution_table

string

Name of the table to store the solution, in [schema_name.]table_name format, using standard name resolution rules. The default value is 'graph_solutions'.

options

map of string to strings

Additional parameters. The default value is an empty map ( {} ).

Supported Parameters (keys)

Parameter Description

max_solution_radius

For ALLPATHS, SHORTEST_PATH and INVERSE_SHORTEST_PATH solvers only. Sets the maximum solution cost radius, which ignores the input parameter destination_nodes list and instead outputs the nodes within the radius sorted by ascending cost. If set to '0.0', the setting is ignored. The default value is '0.0'.

min_solution_radius

For ALLPATHS, SHORTEST_PATH and INVERSE_SHORTEST_PATH solvers only. Applicable only when max_solution_radius is set. Sets the minimum solution cost radius, which ignores the input parameter destination_nodes list and instead outputs the nodes within the radius sorted by ascending cost. If set to '0.0', the setting is ignored. The default value is '0.0'.

max_solution_targets

For ALLPATHS, SHORTEST_PATH and INVERSE_SHORTEST_PATH solvers only. Sets the maximum number of solution targets, which ignores the input parameter destination_nodes list and instead outputs no more than n number of nodes sorted by ascending cost where n is equal to the setting value. If set to 0, the setting is ignored. The default value is '1000'.

uniform_weights

When specified, assigns the given value to all the edges in the graph. Note that weights provided in input parameter weights_on_edges will override this value.

left_turn_penalty

This will add an additonal weight over the edges labelled as 'left turn' if the 'add_turn' option parameter of the /create/graph was invoked at graph creation. The default value is '0.0'.

right_turn_penalty

This will add an additonal weight over the edges labelled as' right turn' if the 'add_turn' option parameter of the /create/graph was invoked at graph creation. The default value is '0.0'.

intersection_penalty

This will add an additonal weight over the edges labelled as 'intersection' if the 'add_turn' option parameter of the /create/graph was invoked at graph creation. The default value is '0.0'.

sharp_turn_penalty

This will add an additonal weight over the edges labelled as 'sharp turn' or 'u-turn' if the 'add_turn' option parameter of the /create/graph was invoked at graph creation. The default value is '0.0'.

num_best_paths

For MULTIPLE_ROUTING solvers only; sets the number of shortest paths computed from each node. This is the heuristic criterion. Default value of zero allows the number to be computed automatically by the solver. The user may want to override this parameter to speed-up the solver. The default value is '0'.

max_num_combinations

For MULTIPLE_ROUTING solvers only; sets the cap on the combinatorial sequences generated. If the default value of two millions is overridden to a lesser value, it can potentially speed up the solver. The default value is '2000000'.

output_edge_path

If true then concatenated edge ids will be added as the EDGE path column of the solution table for each source and target pair in shortest path solves. The default value is false. The supported values are:

true
false

output_wkt_path

If true then concatenated wkt line segments will be added as the Wktroute column of the solution table for each source and target pair in shortest path solves. The default value is true. The supported values are:

true
false

server_id

Indicates which graph server(s) to send the request to. Default is to send to the server, amongst those containing the corresponding graph, that has the most computational bandwidth. For SHORTEST_PATH solver type, the input is split amongst the server containing the corresponding graph.

convergence_limit

For PAGE_RANK solvers only; Maximum percent relative threshold on the pagerank scores of each node between consecutive iterations to satisfy convergence. Default value is 1 (one) percent. The default value is '1.0'.

max_iterations

For PAGE_RANK solvers only; Maximum number of pagerank iterations for satisfying convergence. Default value is 100. The default value is '100'.

max_runs

For all CENTRALITY solvers only; Sets the maximum number of shortest path runs; maximum possible value is the number of nodes in the graph. Default value of 0 enables this value to be auto computed by the solver. The default value is '0'.

output_clusters

For STATS_ALL solvers only; the cluster index for each node will be inserted as an additional column in the output. The default value is false.

Supported Values	Description
true	An additional column 'CLUSTER' will be added for each node
false	No extra cluster info per node will be available in the output

solve_heuristic

Specify heuristic search criterion only for the geo graphs and shortest path solves towards a single target The default value is none.

Supported Values	Description
astar	Employs A-STAR heuristics to speed up the shortest path traversal
none	No heuristics are applied

astar_radius

For path solvers only when 'solve_heuristic' option is 'astar'. The shortest path traversal front includes nodes only within this radius (kilometers) as it moves towards the target location. The default value is '70'.

Output Parameter Description

The GPUdb server embeds the endpoint response inside a standard response structure which contains status information and the actual response to the query. Here is a description of the various fields of the wrapper:

Name

Type

Description

status

String

'OK' or 'ERROR'

message

String

Empty if success or an error message

data_type

String

'solve_graph_response' or 'none' in case of an error

data

String

Empty string

data_str

JSON or String

This embedded JSON represents the result of the /solve/graph endpoint:

Name	Type	Description
result	boolean	Indicates a successful solution on all servers.
result_per_destination_node	array of floats	Cost or Pagerank (based on solver type) for each destination node requested. Only populated if 'export_solve_results' option is set to true.
info	map of string to strings	Additional information.

Empty string in case of an error.