Continuous polarizability

[GoogleCodeExporter]

Implement continuous polarizability (not discrete values, as now), change
-read format accordingly. Possibly implement full tensor of polarizability.
This will open way to many new features, in particular Weighted Discretization.

Original issue reported on code.google.com by yurkin on 26 Nov 2008 at 8:16

• Blocking: Improve accuracy at backscattering direction #167, Self-term for particles near surface #180

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Original comment by yurkin on 23 Aug 2010 at 4:58

• Added labels: Milestone-2011

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Original comment by yurkin on 2 Dec 2010 at 4:39

• Added labels: Priority-High
• Removed labels: Priority-Medium

[GoogleCodeExporter]

Continuous polarizability together with the simplest discretization were 
implemented on a separate branch - r1071. For now it is just a 
proof-of-principle to play with. It will probably find its way into the main 
trunk after the release 1.1. 

r1071 - 2dad88a
https://github.com/adda-team/adda/tree/wd

Original comment by yurkin on 18 Sep 2011 at 6:45

• Added labels: Milestone-1.2
• Removed labels: Milestone-2011

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Original comment by yurkin on 4 Feb 2013 at 5:35

• Removed labels: Milestone-1.2

[GoogleCodeExporter]

Original comment by yurkin on 9 Jul 2013 at 9:10

• Now blocking: Improve accuracy at backscattering direction #167

[GoogleCodeExporter]

Original comment by yurkin on 6 Oct 2013 at 6:41

• Now blocking: Self-term for particles near surface #180

[myurkin]

The workaround is to use many domains - ADDA can use up to 255 (but need to be set in const.h before compilation). Then any continuous distribution of refractive index can be accurately represented by discrete steps. This has been used for the simplest implementation of the weighted discretization in
Liu C., Teng S., Zhu Y., Yurkin M.A., and Yung Y.L. Performance of the discrete dipole approximation for optical properties of black carbon aggregates, J. Quant. Spectrosc. Radiat. Transfer 221, 98–109 (2018).

[TonyaManina]

I will work on it

[myurkin]

Development of the weighted discretization has been performed at a separate branch https://github.com/TonyaManina/adda/tree/wd-21 , but I am not sure that it can be considered an MVP. More testing is required.