Collect and Distribute

When a Collect and Distribute element is encountered in a workflow, the intermediate results from all the iteration units prior to that point are gathered. Based upon metadata and configuration done when launching the workflow, these are distributed as required for downstream steps.

Note: Collect and Distribute elements are only relevant in workflows with upstream Iterate elements.

Configuring a Collect and Distribute element

In the Outputs field of a Collect and Distribute element, terms are entered in a comma separated list. The number of terms determines the number of output channels from the Collect and Distribute element. The connections made between output channels of Collect and Distribute element and input channels of downstream elements specify how those groups of inputs are distributed in the following stage of the workflow. The possible groupings that can be configured when launching are based on metadata. There is, however, no requirement that the names given in the Outputs field of this element and terms used in the metadata match.

The terms entered in the Outputs field are used as names for the output channels, as shown in figure 11.44. These names are also displayed in the wizard when configuring a workflow for launch.

Image workflow_collect_configure_outputs
Figure 11.44: A comma separated list of terms in the Outputs field of the Collect and Distribute element defines the number of output channels and their names.

After selecting the inputs, batch units must be specified using a metadata table. The iterative part(s) of the workflow will be run once for each batch unit, using all the data in that batch unit together. When running such workflows, a workflow result metadata will be generated by default (by this option can be disabled). Read more about workflow result metadata tables in Workflow outputs and workflow result metadata tables.