The document discusses calculation chains in spreadsheets, which refer to the order cells were last calculated but do not include dependency information. The calculation order can change based on dependencies, what cells have changed, and optimizations for multi-threaded calculations. Multi-threaded calculations are split into "child chains" that can be calculated concurrently and "dependency levels" that indicate points where calculation must wait for concurrent threads to complete. An example workbook is referenced to illustrate these concepts.

1. SpreadsheetML
Subject – Calculation Chain

2. Calculation Chain
• The order in which cells were last
calculated
• Does not include dependency information
• Calc order will change, based on:
– Dependency information
– What cells have changed
– Multi-threading optimizations
• Doesn’t force application to calculate in
any particular order

3. Multi-Threaded Calculation
• “Child Chain” (@s) flags indicate subsets
of the calculation chain that can be
calculated concurrently
– Not figured using dependencies, only using
calculation order
• “Dependency Level” (@l) flags indicate
where calculation must wait for all
concurrent threads to complete before
continuing with calculation

4. Example Workbook

5. 1st Calculation

6. 2nd Full Calculation

7. 20th Full Calculation

8. Disclaimer
This presentation is for informational purposes only, and should
not be relied upon as a substitute or replacement for Microsoft
formal file format documentation, which is available at the
following website: https://msdn.microsoft.com/en-
us/library/cc313118(v=office.12).aspx. Any views or opinions
presented in this material are solely those of the author and do
not necessarily represent those of Microsoft. Microsoft
disclaims all liability for mistakes or inaccuracies in this
presentation.