Chaining
========

.. figure:: icons/chaining.png

Profiles objects of one type in the latent space of another object type
through chaining of latent matrices along paths in a data fusion graph.

Signals
-------

**Inputs**:

-  **Fitted Fusion Graph**

   Fitted collective latent data model.

**Outputs**:

-  **Relation**

   Relationships between two groups of objects.

Description
-----------

**Chaining** constructs data profiles of objects of one type that are
expressed in the latent space of another object type. This is done by
appropriately multiplying the latent matrices along paths that connect
start and end nodes in the fusion graph. The widget displays a fitted
fusion graph on the right, where you can select the start and end node
(object type) that are then used in chaining.

.. figure:: images/Chaining1-stamped.png

1. The widget displays all chains that connect selected start node with
   the selected end node (in orange). Click on the chain you wish to
   output.
2. Select what type of chain you wish to output:

   -  **latent space** (widget outputs data profiles in the latent space)
   -  **feature space** (widget outputs data profiles in the original
      domain space)

Example
-------

This widget is great for constructing profiles that relate objects,
which are not directly connected in a fusion graph. In the example below
we have three data sets: annotations of genes from the Gene Ontology,
literature on genes and literature on ontology terms. We use
**Chaining** to see how genes relate to ontology terms.

.. figure:: images/Chaining-Example.png