section h of routines in hex.i

functions in hex.i - h

hex24b_track


    hex24b_track  


Builtin function, documented at i0/hex.i   line 40

SEE hex5_track

hex24f_track


    hex24f_track  


Builtin function, documented at i0/hex.i   line 40

SEE hex5_track

hex5_track


    c= hex5_track(mesh, rays, s)  
    c= hex24f_track(mesh, rays, s)  
    c= hex24b_track(mesh, rays, s)  


track 3 x Nrays x 2 RAYS through the 3D MESH.  RAYS(,,1) are  
points on the rays, while RAYS(,,2) are normalized ray directions.  
The c return value and the S parameter are a long and double  
array respectively, with number of elements equal to the total  
number of intersections of all the RAYS with faces of the MESH,  
plus one for any RAY which misses MESH entirely.  The values of  
c are:  
  [#hits,cell1,cell2,cell3,..., #hits,cell1,cell2,cell3,..., ...]  
where each #hits is followed by the list of cell indices (assuming  
i=1, j=1, and k=1 are present but meaningless in cell arrays --  
that is, assuming zone centered arrays have the same dimensions  
as XYZ rather than one less in each direction).  Rays which miss  
the mesh entirely have #hits=1, all others have #hits>=2 since they  
must exit.  #hits<0 means a ray reentered the mesh for abs(#hits)  
more face crossings, but this currently cannot happen.  The values  
of S correspond to c:  
  [s0,s1,s2,s3,..., s0,s1,s2,s3,..., ...]  
which are the distances along the ray measured from RAYS(,,1) in  
the direction of RAYS(,,2) where the ray pierces a cell face.  For  
rays which miss the mesh, the value of s0 is a diagnostic telling  
why they missed (see compiled code).  
Function hex5_track uses the 5-tet decomposition for hexes,  
which is not unique when the quad faces are non-planar.  You may  
be able to get an idea of this effect by setting hex_triang the  
opposite way and redoing the trace.  
Functions hex24f_track and hex24b_track use the face and body  
centered 24-tet decompositions for hexes.  These are unique;  
however, hex_triang may in rare cases change the trace slightly,  
since the entry search algorithm still involves triangulating  
the surface quads.  
Builtin function, documented at i0/hex.i   line 40

SEE ALSO: hydra_mesh, hex_triang, reg_track, track_reduce, c_adjust, pic3_rays,
conv3_rays

hex_mesh


    mesh= hex_mesh(xyz, bound, nbnds, &mbnds, nblk, &blks, start)  


create a 3D mesh object from the multiblock mesh parameters  
XYZ   is NBLK 3 x Ni x Nj x Nk coordinate arrays packed together  
BOUND is NBLK 3 x Ni x Nj x Nk face boundary markers packed  
NBNDS is length of MBNDS  
MBNDS is HX_blkbnd describing each internal block boundary face  
NBLK  is number of blocks  
BLKS  is NBLK HX_block objects describing the block structure  
START is 0-origin 6*cell+face index of first boundary face/cell  
       or -1-cell to trace from centroid of that cell to point  
       p on ray to begin tracking  
Builtin function, documented at i0/hex.i   line 12

SEE ALSO: hex5_track, hydra_mesh, hex_startflag

hex_mesh2


    mesh= hex_mesh2(xyz, bounds)  


old interface for hex_mesh  
create a 3D mesh object from the 3 x Ni x Nj x Nk coordinate  
array XYZ and the list of 6 BOUNDS:  
  BOUNDS(1), BOUNDS(2)  for the i=1,Ni boundaries  
  BOUNDS(3), BOUNDS(4)  for the j=1,Nj boundaries  
  BOUNDS(5), BOUNDS(6)  for the k=1,Nk boundaries  
The BOUNDS values are:  
  1   if this is a problem boundary  
  2   if this is a reflecting boundary  
  3   if this is a periodic boundary  
Interpreted function, defined at i0/hex.i   line 692

SEE ALSO: hex5_track

hydra_adj


    hydra_adj  


  
     Builtin function, documented at i0/hex.i   line 630

hydra_blks


    hydra_blks  


  
     Builtin function, documented at i0/hex.i   line 611

hydra_bnd


    hydra_bnd  


  
     Builtin function, documented at i0/hex.i   line 616

hydra_mesh


    mesh= hydra_mesh(f)  
 or mesh= hydra_mesh(f, ublk, i0, j0, k0, face)  
 or mesh= hydra_mesh(f, ublk, i0, j0, k0)  


read a 3D mesh object from the hydra PDB/Silo file F.  
Note that the boundary arrays are adjusted to the hex convention  
that cells with i=1, j=1, k=1 are missing, rather than the hydra  
convention that i=imax, j=jmax, k=kmax are missing.  
In the first form, the ray entry search will start on the  
first open boundary face in the mesh.  If the actual problem  
boundary is not convex, you need to identify a surface of  
constant i, j, or k in the problem which is convex, and which  
all the rays you intend to trace intersect.  
UBLK is the user block number (starting from 0),  
I0, J0, K0 are the (1-origin) logical coordinates of a  
  hydra *cell*.  Note that unlike hex cells, the hydra  
  cell bounded by nodes (1,1,1) and (2,2,2) is numbered (1,1,1).  
  (Hex numbers it (2,2,2).)  
FACE is the face number on cell (I0,J0,K0) which you want a  
  ray to enter.  0 means the -I face, 1 the +I face, 2 the -J  
  face, 3 the +J face, 4 the -K face, and 5 the +K face.  
  As you step from this cell to its neighbors, then to their  
  neighbors, and so on, this face must trace out a convex  
  surface for the ray entry search.  Rays not intersecting  
  this surface will not enter the problem; the ray trace  
  will begin at this surface, not at -infinity.  
If FACE==-1 or is omitted (as in the third form), then the  
given points on the rays are assumed to lie inside the mesh,  
and a pseudo ray from the centroid of cell (I0, J0, K0) will be  
tracked to the given point on each ray; the ray will be launched  
into the cell containing that point.  
Interpreted function, defined at i0/hex.i   line 638

SEE ALSO: hex_query, hex5_track, h_data, h_openb

hydra_mrk


    hydra_mrk  


  
     Builtin function, documented at i0/hex.i   line 624

hydra_start


    hydra_start, mesh, start  


change the starting cell of the hydra MESH (returned by hydra_mesh)  
to START.  If called as a function, returns old start value.  
Interpreted function, defined at i0/hex.i   line 784