Configure the K-Core component - Platform For AI

The k-core algorithm is used to find the subgraph with the specified coreness in a graph. The k-core of a graph refers to the remaining subgraph after vertices with the degree k or a lower degree are repeatedly excluded. The K-Core component can generate the vertices that are connected to each vertex in the subgraph.

Configure the component

Method 1: Configure the component on the pipeline page

You can add the K-Core component on the pipeline page of Machine Learning Designer in the Platform for AI (PAI) console. The following table describes the parameters.

Tab	Parameter	Description
Fields Setting	Source Vertex Column	The start vertex column in the edge table.
Fields Setting	Target Vertex Column	The end vertex column in the edge table.
Parameters Setting	k	The coreness of a vertex. Default value: 1. If a vertex belongs to the k-core but is not included in the (k+1)-core, the coreness of the vertex is k.
Tuning	Workers	The number of vertices for parallel job execution. The degree of parallelism and framework communication costs increase with the value of this parameter.
Tuning	Memory Size per Worker	The maximum size of memory that a single job can use. Unit: MB. Default value: 4096. If the size of used memory exceeds the value of this parameter, the `OutOfMemory` error is reported.

Method 2: Configure the component by using PAI commands

You can configure the K-Core component by using PAI commands. You can use the SQL Script component to run PAI commands. For more information, see Scenario 4: Execute PAI commands within the SQL script component in the "SQL Script" topic.

PAI -name KCore
    -project algo_public
    -DinputEdgeTableName=KCore_func_test_edge
    -DfromVertexCol=flow_out_id
    -DtoVertexCol=flow_in_id
    -DoutputTableName=KCore_func_test_result
    -Dk=2;

Parameter	Required	Default value	Description
inputEdgeTableName	Yes	No default value	The name of the input edge table.
inputEdgeTablePartitions	No	Full table	The partitions in the input edge table.
fromVertexCol	Yes	No default value	The start vertex column in the input edge table.
toVertexCol	Yes	No default value	The end vertex column in the input edge table.
outputTableName	Yes	No default value	The name of the output table.
outputTablePartitions	No	No default value	The partitions in the output table.
lifecycle	No	No default value	The lifecycle of the output table.
workerNum	No	Not specified	The number of vertices for parallel job execution. The degree of parallelism and framework communication costs increase with the value of this parameter.
workerMem	No	4096	The maximum size of memory that a single job can use. Unit: MB. Default value: 4096. If the size of used memory exceeds the value of this parameter, the `OutOfMemory` error is reported.
splitSize	No	64	The data split size.
k	Yes	1	The coreness of a vertex.

Example

Add the SQL Script component as a vertex to the canvas and execute the following SQL statements to generate training data.

drop table if exists KCore_func_test_edge;
create table KCore_func_test_edge as
select * from
(
  select '1' as flow_out_id,'2' as flow_in_id
  union all
  select '1' as flow_out_id,'3' as flow_in_id
  union all
  select '1' as flow_out_id,'4' as flow_in_id
  union all
  select '2' as flow_out_id,'3' as flow_in_id
  union all
  select '2' as flow_out_id,'4' as flow_in_id
  union all
  select '3' as flow_out_id,'4' as flow_in_id
  union all
  select '3' as flow_out_id,'5' as flow_in_id
  union all
  select '3' as flow_out_id,'6' as flow_in_id
  union all
  select '5' as flow_out_id,'6' as flow_in_id
)tmp;

Data structure

Add the SQL Script component as a vertex to the canvas and run the following PAI commands to train the model.

drop table if exists ${o1};
PAI -name KCore
    -project algo_public
    -DinputEdgeTableName=KCore_func_test_edge
    -DfromVertexCol=flow_out_id
    -DtoVertexCol=flow_in_id
    -DoutputTableName=${o1}
    -Dk=2;

Right-click the SQL Script component and choose View Data > SQL Script Output to view the training results.

| node1 | node2 |
| ----- | ----- |
| 1     | 2     |
| 1     | 3     |
| 1     | 4     |
| 2     | 1     |
| 2     | 3     |
| 2     | 4     |
| 3     | 1     |
| 3     | 2     |
| 3     | 4     |
| 4     | 1     |
| 4     | 2     |
| 4     | 3     |