Standard Library

bowtie

DOCUMENT map= bowtie(rt, zt)
      or map= bowtie(rt, zt, ireg)
  returns a "bowtie map" for the quadrilateral mesh defined by
  RT, ZT, and (optionally) IREG.  If IREG is present, it should be
  an integer array of the same dimensions as RT and ZT; its first
  row and column are ignored, otherwise each non-zero element of
  IREG marks an existing zone in the mesh.  (An IREG with one fewer
  row and column than RT and ZT will also be accepted.)  If IREG
  is omitted, every zone is presumed to exist.

  The returned MAP is a 2-D integer array with one fewer row and
  column than RT and ZT.  It's values have the following meanings:

       2   marks a convex zone with positive area
       1   marks a concave (boomerang) zone with positive area
       0   marks a bowtied zone
      -1   marks a concave (boomerang) zone with negative area
      -2   marks a convex zone with negative area
      -9   marks a non-existent zone

  Use the nbow function to print the results.

SEE ALSO: nbow

nbow

DOCUMENT nbow, map
      or nbow, file
      or nbow, rt, zt
      or nbow, rt, zt, ireg
  prints information about topological oddities in a mesh.
  MAP is a bowtie map as returned by the bowtie function.
  FILE is a binary file containing rt, zt, and ireg arrays.
  RT, ZT and IREG are 2-D arrays defining a quadrilateral mesh.

  The information printed includes the zone index (corner with
  the largest indices) of zones which are concave (boomerangs)
  or bowtied, and of zones with negative area.  You can set
  the global variable nbow_negative to 1 to reverse the default
  sense of positive area.  By default, only the first 10 zones
  in each category are printed; use the all=1 keyword argument
  to print a complete (and maybe very long) list.

SEE ALSO: bowtie

nbow_negative

DOCUMENT nbow_negative
  default value is 0
  set to 1 to reverse the sense of positive area for the nbow function