gradient-analysis.md

@@ -3,7 +3,18 @@ UNDER CONSTRUCTION
 Photoelatic image: gradient analysis
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+1. Motivation
+Shortcomes of the inverse solver: initial gauss sensitivity (fig), slower, not working for non-disc particles right now.
 
+2. $`G^2`$ description and its history
+
+3. $`G^2`$ as a global pressure indicator: global calibrations and different shapes.
+
+4. $`G^2`$ as a particle scale stress indicator: particle scale calibration and simulations: what are the factors that scale with $`G^2`$?
+
+5. $`G^2`$ as a contact scale stress indicator: citation and how accurate it is, connection to the inverse solver
+
+6. A sample code to calculate $`G^2`$.