Bug: Triangualte with 'a' and small values <10 ** -4 about triangle

[icemtel]

Getting detailed Triangle output (removed "Q", added "V" option, info) when triangulating a square of length=0.1 with option 'a0.00001'

Constructing Delaunay triangulation by divide-and-conquer method.
  Sorting vertices.
  Forming triangulation.
  Removing ghost triangles.
  Enclosing convex hull with segments.
Adding Steiner points to enforce quality.
  Looking for encroached subsegments.
  Making a list of bad triangles.
  Splitting bad triangles.

Writing vertices.
Writing triangles.
Writing edges.

Statistics:

  Input vertices: 4

  Mesh vertices: 4
  Mesh triangles: 2
  Mesh edges: 5
  Mesh exterior boundary edges: 4

Mesh quality statistics:

  Smallest area:             0.02   |  Largest area:             0.02
  Shortest edge:              0.2   |  Longest edge:          0.28284
  Shortest altitude:      0.14142   |  Largest aspect ratio:        2

  Triangle aspect ratio histogram:
  1.1547 - 1.5       :         0    |     15 - 25         :         0
     1.5 - 2         :         2    |     25 - 50         :         0
       2 - 2.5       :         0    |     50 - 100        :         0
     2.5 - 3         :         0    |    100 - 300        :         0
       3 - 4         :         0    |    300 - 1000       :         0
       4 - 6         :         0    |   1000 - 10000      :         0
       6 - 10        :         0    |  10000 - 100000     :         0
      10 - 15        :         0    | 100000 -            :         0
  (Aspect ratio is longest edge divided by shortest altitude)

  Smallest angle:              45   |  Largest angle:              90

  Angle histogram:
      0 -  10 degrees:         0    |     90 - 100 degrees:         0
     10 -  20 degrees:         0    |    100 - 110 degrees:         0
     20 -  30 degrees:         0    |    110 - 120 degrees:         0
     30 -  40 degrees:         0    |    120 - 130 degrees:         0
     40 -  50 degrees:         4    |    130 - 140 degrees:         0
     50 -  60 degrees:         0    |    140 - 150 degrees:         0
     60 -  70 degrees:         0    |    150 - 160 degrees:         0
     70 -  80 degrees:         0    |    160 - 170 degrees:         0
     80 -  90 degrees:         2    |    170 - 180 degrees:         0

Memory allocation statistics:

  Maximum number of vertices: 4
  Maximum number of triangles: 6
  Maximum number of subsegments: 4
  Approximate heap memory use (bytes): 816

Algorithmic statistics:

  Number of incircle tests: 1
  Number of 2D orientation tests: 12

Triangulating the same geometry with 'a0.001'

Constructing Delaunay triangulation by divide-and-conquer method.
  Sorting vertices.
  Forming triangulation.
  Removing ghost triangles.
  Enclosing convex hull with segments.
Adding Steiner points to enforce quality.
  Looking for encroached subsegments.
  Making a list of bad triangles.
  Splitting bad triangles.

Writing vertices.
Writing triangles.

Statistics:

  Input vertices: 4

  Mesh vertices: 41
  Mesh triangles: 68
  Mesh edges: 108
  Mesh exterior boundary edges: 12

Mesh quality statistics:

  Smallest area:       7.8125e-05   |  Largest area:       0.00094578
  Shortest edge:         0.027869   |  Longest edge:              0.1
  Shortest altitude:    0.0015625   |  Largest aspect ratio:       64

  Triangle aspect ratio histogram:
  1.1547 - 1.5       :        11    |     15 - 25         :         0
     1.5 - 2         :        33    |     25 - 50         :         0
       2 - 2.5       :        12    |     50 - 100        :         2
     2.5 - 3         :         5    |    100 - 300        :         0
       3 - 4         :         3    |    300 - 1000       :         0
       4 - 6         :         1    |   1000 - 10000      :         0
       6 - 10        :         1    |  10000 - 100000     :         0
      10 - 15        :         0    | 100000 -            :         0
  (Aspect ratio is longest edge divided by shortest altitude)

  Smallest angle:          1.7899   |  Largest angle:          176.42

  Angle histogram:
      0 -  10 degrees:         4    |     90 - 100 degrees:        12
     10 -  20 degrees:         2    |    100 - 110 degrees:         4
     20 -  30 degrees:         4    |    110 - 120 degrees:         3
     30 -  40 degrees:        25    |    120 - 130 degrees:         1
     40 -  50 degrees:        55    |    130 - 140 degrees:         1
     50 -  60 degrees:        30    |    140 - 150 degrees:         1
     60 -  70 degrees:        20    |    150 - 160 degrees:         0
     70 -  80 degrees:        20    |    160 - 170 degrees:         0
     80 -  90 degrees:        20    |    170 - 180 degrees:         2

Memory allocation statistics:

  Maximum number of vertices: 42
  Maximum number of triangles: 69
  Maximum number of subsegments: 12
  Maximum number of encroached subsegments: 1
  Maximum number of bad triangles: 55
  Maximum number of stacked triangle flips: 5
  Approximate heap memory use (bytes): 9584

Algorithmic statistics:

  Number of incircle tests: 533
  Number of 2D orientation tests: 256
  Number of triangle circumcenter computations: 65

The only difference I can see is "Writing edges." line..

[icemtel]

drufat#26 (comment)