computeEgoGraph: Find the vertices not farther than a given limit from another...

In teradata-aster-field/toaster: Big Data in-Database Analytics that Scales with Teradata Aster Distributed Platform

Description

Find the vertices not farther than a given limit from another fixed vertex, and create egographs (subgraphs) with the given order parameter.

Usage

computeEgoGraph(channel, graph, ego, order = 1, mode = "all",
  createDistanceAttr = TRUE, distanceAttrname = "ego.distance",
  vertexWhere = graph$vertexWhere, edgeWhere = graph$edgeWhere,
  allTables = NULL, test = FALSE)

Arguments

channel	connection object as returned by odbcConnect
graph	an object of class 'toagraph' referencing graph tables in Aster database.
ego	list of vertices for which the calculation of corresponding ego graphs is performed.
order	integer giving the order of the ego graph neighborhood.
mode	character constant, it specifies how to use the direction of the edges if a directed graph is analyzed. For 'out' only the outgoing edges are followed, so all vertices reachable from the source vertex in at most order steps are counted. For 'in' all vertices from which the source vertex is reachable in at most order steps are counted. 'all' ignores the direction of the edges. This argument is ignored for undirected graphs.
createDistanceAttr	logical: indicates if vertices should receive attribute with the distance to ego graph centeral vertex.
distanceAttrname	name of the vertex distance attribute.
vertexWhere	SQL WHERE clause limiting data from the vertex table. This value when not null overrides corresponding value vertexWhere from graph (use SQL as if in WHERE clause but omit keyword WHERE).
edgeWhere	SQL WHERE clause limiting data from the edge table. This value when not null overrides corresponding value edgeWhere from graph (use SQL as if in WHERE clause but omit keyword WHERE).
allTables	pre-built information about existing tables.
test	logical: if TRUE show what would be done, only (similar to parameter test in RODBC functions: sqlQuery and sqlSave).

Examples

if(interactive()) {
library(GGally)

policeGraphDi = toaGraph(vertices = "dallaspolice_officer_vertices", 
                         edges = "dallaspolice_officer_edges_di", 
                         directed = TRUE,
                         key = "officer", source = "officer1", target = "officer2", 
                         vertexAttrnames = c("offense_count"),
                         edgeAttrnames = c("weight"))
               
# initialize connection to Lahman baseball database in Aster 
conn = odbcDriverConnect(connection="driver={Aster ODBC Driver};
                         server=<dbhost>;port=2406;database=<dbname>;uid=<user>;pwd=<pw>")
                         
setVertexColor <- function(graph, vertex, color="red", default="grey") {
  graph %v% "color" = 
  ifelse(get.vertex.attribute(graph, "vertex.names") == as.character(vertex),
         color, default)
  
  return(graph)
}

topPagerankPolice = computeGraphMetric(conn, policeGraphDi, type='pagerank', top=3)
egoCenters = as.list(as.character(topPagerankPolice$key))

egoGraphsTopPagerank = computeEgoGraph(conn, policeGraphDi, order = 1, ego = egoCenters)

egoGraph = setVertexColor(egoGraphsTopPagerank[[1]], egoCenters[[1]])
ggnet2(egoGraph, node.label="vertex.names",  node.size="offense_count",
       legend.position="none", color="color")

egoGraph = setVertexColor(egoGraphsTopPagerank[[2]], egoCenters[[2]])
ggnet2(egoGraph, node.label="vertex.names",  node.size="offense_count",
       legend.position="none", color="color")

egoGraph = setVertexColor(egoGraphsTopPagerank[[3]], egoCenters[[3]])
ggnet2(egoGraph, node.label="vertex.names",  node.size="offense_count",
       legend.position="none", color="color")
}

teradata-aster-field/toaster documentation built on May 31, 2019, 8:36 a.m.