program m1      include 'p4f.h'*-----*  file:-  norm_master.f*  related files:-  *    norm_slave.f         (slave program)*    norm_<hostname>.pg   (process group file)**  Test program for new p4 library.*    Generate matrix,*    distribute columns to slaves,*    get sum norm of columns, verify and display result.**  features:-*    max vector length <= `NMAX'.  If you increase this value,*            be sure to increase the same value in slave program, too.*    4 data byte per integer (controlled by `LENINT')*    4 data byte per item    (real; controlled by `LENREAL')*  *  Debug code disabled by `c$$$'.*  status:- plain vanilla, no error control*  Volker Kurz, ANL & U Frankfurt, 04-Oct-91*-----*     .. p4 routines ..      external   p4init, p4crpg, p4ntotids, p4send, p4recv, p4cleanup,     $     p4clock**     .. constants ..      integer    NMAX,      LENINT,   LENREAL,   OFF      parameter (NMAX=200 , LENINT=4, LENREAL=4, OFF=-1)      integer    TAGCNT,    TAGDAT,    TAGNEW,    TAGEND      parameter (TAGCNT=10, TAGDAT=20, TAGNEW=30, TAGEND=40)**     .. variables and arrays ..      integer    nslaves, i, k, mnsl, time1, time2,     $     iretcd, ireclen, ip, msglen, itype      real       a(NMAX, NMAX), r(NMAX), rnorm      logical    errors*-----*      write (*,*) 'setting up parallel environment...'*      call p4init ()      call p4crpg ()      nslaves = p4ntotids() - 1*      write (*,*) 'initializing matrix...'*      do 1 k=1,NMAX         a(1,k) = float (k+1)         do 11 i=2,NMAX            a(i,k) = 1.0 11      continue 1    continue*-----------------------------------------------------------------------*  Beginning of main loop*  ~~~~~~~~~~~~~~~~~~~~~~ 2    continue**  Ask for number of rows and columns.*  Provide a condition to end the program.*  Watch out, if they want to fool us by entering too big numbers.*  Calculate message length for slave data.*  Broadcast vector length to slaves.*      write (*,9993) NMAX      read (*,*) m      if (m.lt.1) then         goto 7      elseif (m.gt.NMAX) then         m = NMAX         write (*,*) 'value truncated to m = ',m      endif      write (*,9995) NMAX      read (*,*) n      if (n.lt.1) then         goto 7      elseif (n.gt.NMAX) then         n = NMAX         write (*,*) 'value truncated to n = ',n      endif*      msglen = m * LENREAL      time1 = p4clock()*      do 3 i=1,nslaves         call p4send (TAGCNT, i, m, LENINT, iretcd) 3    continue**  Compute norms of columns*  ~~~~~~~~~~~~~~~~~~~~~~~~*  Process columns by strips of length 'nslaves'.*  'mnsl' ensures that only 'n' columns are processed.*  1st sweep dials out columns,*  2nd sweep collects results.*        do 4 i=1,n,nslaves*        .. distribute columns to slaves ..         mnsl = min ( n-i+1, nslaves )          do 41 k=1,mnsl*           .. send column i+k-1 to slave k ..            call p4send (TAGDAT, k, a(1,i+k-1), msglen, iretcd) 41      continue         do 42 k=1,mnsl*           .. receive norm from slave ..            itype = TAGDAT            ip = OFF            call p4recv (itype, ip, rnorm, LENREAL, ireclen, iretcd)*           .. result is for column i+ip-1 ..            r(i+ip-1) = rnorm 42      continue 4    continue       time2 = p4clock()**  Check results and report any errors.  *  Norm of column k is:  #rows + k*  Note: There should be no rounding errors!*      errors = .FALSE.      do 5 k=1,n         if (r(k).ne.m+k) then            write (*,9999) k, m+k, r(k)            errors = .TRUE.         endifc$$$         write (*,*) 'norm of col', k,' is:', r(k) 5    continue      if (errors) then         write (*,*) 'mission completed, error(s) detected.'      else         write (*,*) 'mission completed, no errors detected.'      endif      write (*,9997) float (time2-time1) / 1000.0**  Tell slaves to get ready for a new session.*  Data is ignored, when slave detects data type TAGNEW.*      do 6 i=1,nslaves         call p4send (TAGNEW, i, m, LENINT, iretcd) 6    continue**  End of main loop*  ~~~~~~~~~~~~~~~~      goto 2 7    continue*------------------------------------------------------------------------------**  Terminate parallel session*  ~~~~~~~~~~~~~~~~~~~~~~~~~~*  Broadcast TAGEND signal to all slaves.*  A slave will terminate, when TAGEND is detected,*  the contents of the message will be ignored.*      do 8 i=1,nslaves         call p4send (TAGEND, i, n, LENINT, iretcd) 8    continue      call p4cleanup*-----      stop 9993 format(1x,'-----'/     $     ' input number of rows (1 <= m <=',i7,')'/     $     ' (any value <= 0 terminates program)') 9995 format(1x,     $     ' input number of columns (1 <= n <=',i7,')'/     $     ' (any value <= 0 terminates program)') 9997 format(1x,'time :',f12.3,' s') 9999 format(1x,'Error in column ',i7/     $     '   norm should be       :',i10/     $     '   but computed value is:',e14.4)      end