Neighborhood analysis

Concept

The neighborhood analysis is a tool available in Dynamo that is meant to help describe the local spatial relationships of particles, especially after STA. As such, it is implemented in Dynamo as a function that analyses partilces through their LINKalignment tablesLINK.

Aligned particles are described LINKEULER ANGLE CONVENTIONSLINK

FIGURE FIGUREFIGURE

Function call

The most basic way to call the neighborhood analysis function is:
analysisOfmyTable = dpktbl.neighborhood.analize(myTable)

Where myTable is the table describing the set of aligned particle in the usual Dynamo format.

dpktbl.neighborhood.analize has a set of optional parameters:

1. distance: this is the maximal allowed distance between particles to still be analysed. The distance is measured in pixels between the centers of the particles after alignment. The default value is 5 pixels. This value should be kept reasonably small, so as to highlight short-range repeating spatial relationships as well as to reduce computing time.
2. modelColumn: this indicates which column of the table is used to separate the particles into groups. Particles in different groups cannot be considered as neighbors. The default column is 21 ("reg").
3. secondTable: this options changes the behaviour of the function. If this option is active, the distribution of particles defined in the second table will be analysed as seen from the particles in the original table. This option is deactivated by default.
4. indices: this options allows for the analysis of only a subset of the groups defined by modelColumn. By default all groups are analysed.

The output analysisOfmyTable is a structure. It contains three main fields: .originalTable, .coupleTable and .couples. .originalTable is merely a copy of the input table. .coupleTable is the table that records the geometric relationships between pairs of particles, in particular the distance vector is recordes in columns 24, 25 and 26 (x,y,z following the Dynamo table conventions). .couples records the indexes of the particles that make a pair in the original table. As such, .coupleTable will have the same number of rows as .couples.tbl.