#include <misc.h>#include <params.h>subroutine trunc!-----------------------------------------------------------------------!! Purpose:! Check consistency of truncation parameters and evaluate pointers! and displacements for spectral arrays!! Original version:  CCM1!!-----------------------------------------------------------------------!! $Id: trunc.F90,v 1.3 2001/09/16 22:13:35 rosinski Exp $! $Author: rosinski $!!-----------------------------------------------------------------------  use precision  use pmgrid  use pspect  use comspe  implicit none!---------------------------Local variables-----------------------------!  integer n              ! Loop index over diagonals  integer ik2            ! K+2  integer m              ! loop index!!-----------------------------------------------------------------------!! trunc first evaluates truncation parameters for a general pentagonal ! truncation for which the following parameter relationships are true!! 0 .le. |m| .le. ptrm!! |m| .le. n .le. |m|+ptrn for |m| .le. ptrk-ptrn!! |m| .le. n .le. ptrk     for (ptrk-ptrn) .le. |m| .le. ptrm!! Most commonly utilized truncations include:!  1: triangular  truncation for which ptrk=ptrm=ptrn!  2: rhomboidal  truncation for which ptrk=ptrm+ptrn!  3: trapezoidal truncation for which ptrn=ptrk .gt. ptrm!! Simple sanity check! It is necessary that ptrm .ge. ptrk-ptrn .ge. 0!  if (ptrm.lt.(ptrk-ptrn)) then     write(6,*)'TRUNC: Error in truncation parameters'     write(6,*)'       ntrm.lt.(ptrk-ptrn)'     call endrun  end if  if (ptrk.lt.ptrn) then     write(6,*)'TRUNC: Error in truncation parameters'     write(6,*)'       ptrk.lt.ptrn'     call endrun  end if!! Evaluate pointers and displacement info based on truncation params!! The following ifdef logic seems to have something do with SPMD ! implementation, although it's not clear how this info is used! Dave, can you check this with JR?!  ncoefi(1) = 1  ik2 = ptrk + 2  do n=1,pmax     ncoefi(n+1) = ncoefi(n) + min0(pmmax,ik2-n)     nalp(n) = ncoefi(n) - 1     nco2(n) = ncoefi(n)*2     nm(n) = ncoefi(n+1) - ncoefi(n)  end do  nstart(1) = 0  nlen(1) = ptrn + 1  do m=2,pmmax     nstart(m) = nstart(m-1) + nlen(m-1)     nlen(m) = min0(ptrn+1,ptrk+2-m)  end do!      write(6,*)'Starting index  length'!      do m=1,ptrm+1!         write(6,'(1x,i14,i8)')nstart(m),nlen(m)!      end do!! Define break-even point for vector lengths in GRCALC.  Don't implement! for non-PVM machines!  ncutoff = pmax#if ( defined PVP )  if (2*nm(1).lt.plev) ncutoff = 0  do n=2,pmax,2     if (2*nm(n).lt.plev) then        ncutoff = n        goto 100     end if  end do100 continue  write(6,*)'TRUNC: n cutoff for GRCALC vectorization = ',ncutoff#endif!  returnend subroutine trunc