#1571 degree variance evolution

[ChristopherLausch]

Added an operators to calculate the degree variance evolution for a temporal graph.

Description

A graph to value operator that calculates the degree variance of a temporal graph. The result is a dataset of Tuple3<Long,Long,Float> where the tuple positions represent the following:

1. the interval start
2. the interval end
3. the value for that interval

Related Issue

#1571

How Has This Been Tested?

Unit Tests with a test graph

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly (if necessary).
• I have added tests to cover my changes.
• All new and existing tests passed.
• I ran a spell checker.