%N pgsubp %F $MIR/src/pgsubp.f
%D Subdivide view surface into panels
%B
      SUBROUTINE PGSUBP (NXSUB, NYSUB)
      INTEGER NXSUB, NYSUB

 PGPLOT divides the physical surface of the plotting device (screen,
 window, or sheet of paper) into NXSUB x NYSUB `panels'. When the 
 view surface is sub-divided in this way, PGPAGE moves to the next
 panel, not the next physical page. The initial subdivision of the
 view surface is set in the call to PGBEG. When PGSUBP is called,
 it forces the next call to PGPAGE to start a new physical page,
 subdivided in the manner indicated. No plotting should be done
 between a call of PGSUBP and a call of PGPAGE (or PGENV, which calls
 PGPAGE).

 If NXSUB > 0, PGPLOT uses the panels in row order; if <0, 
 PGPLOT uses them in column order, e.g.,

  NXSUB=3, NYSUB=2            NXSUB=-3, NYSUB=2   

 +-----+-----+-----+         +-----+-----+-----+
 |  1  |  2  |  3  |         |  1  |  3  |  5  |
 +-----+-----+-----+         +-----+-----+-----+
 |  4  |  5  |  6  |         |  2  |  4  |  6  |
 +-----+-----+-----+         +-----+-----+-----+

 PGPLOT advances from one panels to the next when PGPAGE is called,
 clearing the screen or starting a new page when the last panel has
 been used. It is also possible to jump from one panel to another
 in random order by calling PGPANL.

 Arguments:
  NXSUB  (input)  : the number of subdivisions of the view surface in
                    X (>0 or <0).
  NYSUB  (input)  : the number of subdivisions of the view surface in
                    Y (>0).
