CFD Utilities Files

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!
      program deconstruct
!
!     Description:
!
!        (Originally, for testing unstructured grid forms oF ADT searching:)
!
!        Convert a multiblock structured surface or volume grid to a surface
!     triangulation or tetrahedral volume mesh.  Quadrilaterals become pairs
!     of triangles; hex cells become five tetrahedra each.
!
!        (This version:)
!
!        Preserving the input quad surface cells or hex volume cells is now
!     an option, as needed for use by US3D,  Avoiding duplicate vertices is
!     an added complication, that has initially been handled with a "brute-
!     force" method that will be slow on a large grid.
!
!        Outputs are in Tecplot format, as a single zone.
!
!        This version now allows for an accompanying function file that has
!     to be vertex-centered.  Note that a cell-centered output from DPLR is
!     really the grid formed by the cell centroids along with the cell-cen-
!     tered solution at those centroids,  so the files are actually vertex-
!     centered.   Output many be in either point or block order, the latter
!     being more efficient for Tecplot.
!
!        A function file option has NOT been implemented for the original
!     cell-splitting options.
!
!     Control File Format (standard input):
!
!        surface_grid.g               ! Structured grid
!        none                         ! Matching flow solution
!        n                            ! Subdivide cells?
!        y                            ! Eliminate repeated (x,y,z)s?
!        unstructured-unique-surf.dat ! Unstructured output (Tecplottable)
!        y                            ! Point order? n = block order
!
!
!     Procedures:
!
!        triangulation_io  I/O utilities for unstructured data
!        xyzq_io package   I/O utilities for PLOT3D grid and function files
!
!     History:
!
!        08/16/04  D.A.Saunders  Initial adaptation of EXTRACT_BLOCKS, to
!                                provide data for testing the tetrahedral mesh
!                                variant of the ADT search package.
!        09/25/2022   "     "    Option to preserve quad/hex cells.
!                                Duplicate vertices are NOT suppressed.
!        10/14/2022   "     "    75 years since Chuck Yeager/Bell X-1/Mach 1+.
!                                Debugging proved unusually difficult.
!                                Performance on a big volume grid may be
!                                intolerable.  Example: a 6-block volume grid
!                                with 942590 points required about 17 minutes
!                                with no function data.
!        10/18-21/22  "     "    Handled optional function data, starting with
!                                introduction of triangulation_io.  This means
!                                working with xyz(3,npoints) rather than the
!                                original x,y,z vectors.
!        10/23/2022   "     "    An input control file can be used in lieu of
!                                interactive inputs.
!        03/25/2024   "     "    Block order output request is ignored because
!                                triangulation_io doesn't support it.  Tell the
!                                user to convert to block order within Tecplot.
!        12/04/2024   "     "    Fixed a typo in the History.
!
!     Author:  David Saunders, ELORET, Inc. at NASA Ames Research Center, CA.
!              Now with AMA, Inc. at Ames.
!
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