functions in hex.i - h

 hex24b_track  
 
builtin function, documented at i0/hex.i   line 38  

 hex24f_track  
 
builtin function, documented at i0/hex.i   line 38  

             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 38  

             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 10  

             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 585  

             start= hex_query(mesh, xyz, bound, mbnds, blks)  
 
     query a mesh created by hex_mesh, returning the arrays  
     passed to that function (these are not copies -- be careful  
     not to clobber them)  
     function return value is the start index  
builtin function, documented at i0/hex.i   line 27  

             old_flag= hex_startflag(new_flag)  
 
     possibly set flag to NEW_FLAG, always return OLD_FLAG, where  
     flag value is 0 (default) to begin search for new entry point  
     at previous entry point, 1 to begin search for new entry point  
     from mesh start face for every ray.  Any other value of NEW_FLAG  
     returns OLD_FLAG without changing it.  
builtin function, documented at i0/hex.i   line 489  

             old_flag= hex_triang(new_flag)  
 
     possibly set flag to NEW_FLAG, always return OLD_FLAG, where  
     flag value is 0 for default mesh triangulation, 1 for opposite  
     triangulation, and 2 on input to signal not to change the  
     current value.  The triangulation value can affect the result  
     of hex5_track if the quad faces of the mesh are not planar.  
builtin function, documented at i0/hex.i   line 474  

 hydra_adj  
 
  
builtin function, documented at i0/hex.i   line 523  

 hydra_blks  
 
  
builtin function, documented at i0/hex.i   line 504  

 hydra_bnd  
 
  
builtin function, documented at i0/hex.i   line 509  

             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 531  

 hydra_mrk  
 
  
builtin function, documented at i0/hex.i   line 517  

             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 677