Dashboard Spatial Integrals Plot

[sleigh2022]

Working on implementing interactive plots of spatial integrals of fluid variables within the RMK dashboard.

Spatial integrals of variables are highly useful for checking quantity conservation and studying physical terms.

To do:

• Basic plotting of spatial domain integrals of fluid variables with respect to time
• Display total as an additional curve, with Checkbox widget
• Display plot either as lines or as a Stacked Area plot, with Checkbox widget
• StackedArea plot needs to properly stack datasets that change sign; try splitting data into positive and negative parts and plotting separately.
• Option to group/summate variable data by model - possibly for general use, but is useful for spatial integral plots.
• Fetch the current matplotlib colour cycle for line plots (currently implemented for area plots).
• Possibly merge Spatial Integral panel into Multi Variable panel as a third button alongside "Fixed x" and "Fixed t".

[sleigh2022]

After discussion today:

• Total Curve is partially implemented for line plot only. Total Curve should later be used in other plot formats as well and be toggled using a checkbox widget.

• Spatial integrals won't be part of v2.0.0, but will be in a later version.

• To properly make use of the functionality of stacking and integrating whole groups of variables like source terms, this requires additional work on the Variable selector, and some ways to programmatically select groups of variables based on evolved variable, model terms etc. These could be added as getters for VariableContainer, then called within or prior to Dashboard.