Program x06ajfe

!     X06AJF Example Program Text

!     Mark 29.3 Release. NAG Copyright 2023.

!     .. Use Statements ..
      Use nag_library, Only: x06aaf, x06abf, x06ajf, x06akf
!     .. Implicit None Statement ..
      Implicit None
!     .. Local Scalars ..
      Integer                          :: ifail, inner_num, inner_threads,     &
                                          max_active_levels, outer_threads,    &
                                          total, total_2, total_3
!     .. Executable Statements ..

!     Initialise totals
      total = 0
      total_2 = 0
      total_3 = 0

!     Set number of threads for inner and outer parallel regions
      inner_threads = 7
      outer_threads = 3
      ifail = 0
      Call x06aaf(outer_threads,ifail)

!     Testing implementation default behaviour

      !$Omp Parallel Shared (inner_threads,total,inner_num,ifail),             &
      !$Omp   Default (None)

        !$Omp Master
          Write (*,99997) 'Implementation max active levels default:',         &
            x06akf()
          Write (*,99998) 'No. threads in 1st parallel region:', x06abf()
        !$Omp End Master

        ifail = 0
        !$Omp Barrier
        Call x06aaf(inner_threads,ifail)

        !$Omp Parallel Shared (total,inner_num), Default (None)

!         Get max number of threads inside second active parallel region
          inner_num = x06abf()

          !$Omp Atomic
            total = total + 1
          !$Omp End Atomic

        !$Omp End Parallel

        !$Omp Master
          Write (*,99998) 'No. threads in 2nd parallel region:', inner_num
        !$Omp End Master

      !$Omp End Parallel

      Write (*,99999) 'Total threads:', total
      Write (*,*)
      Write (*,*)

!     Set max active parallel regions
      max_active_levels = 2
      ifail = 0
      Call x06ajf(max_active_levels,ifail)

!     Set number of threads for inner and outer parallel regions
      inner_threads = 7
      outer_threads = 3
      ifail = 0
      Call x06aaf(outer_threads,ifail)

!     Testing with max active levels set to 2

      !$Omp Parallel Shared (inner_threads,total_2,inner_num,ifail,            &
      !$Omp   max_active_levels), Default (None)

        !$Omp Master
          Write (*,99996) 'Max active levels set to:', max_active_levels
          Write (*,99995) 'x06ak return value:', x06akf()
          Write (*,99998) 'No. threads in 1st parallel region:', x06abf()
        !$Omp End Master

        ifail = 0
        !$Omp Barrier
        Call x06aaf(inner_threads,ifail)

        !$Omp Parallel Shared (total_2,inner_num), Default (None)

!         Get max number of threads inside second active parallel region
          inner_num = x06abf()

          !$Omp Atomic
            total_2 = total_2 + 1
          !$Omp End Atomic

        !$Omp End Parallel

        !$Omp Master
          Write (*,99998) 'No. threads in 2nd parallel region:', inner_num
        !$Omp End Master

      !$Omp End Parallel

      Write (*,99999) 'Total threads:', total_2
      Write (*,*)
      Write (*,*)

!     Set max active parallel regions
      max_active_levels = 1
      ifail = 0
      Call x06ajf(max_active_levels,ifail)

!     Testing with max active levels set to 1

      !$Omp Parallel Shared (inner_threads,total_3,inner_num,ifail,            &
      !$Omp   max_active_levels), Default (None)

        !$Omp Master
          Write (*,99996) 'Max active levels set to:', max_active_levels
          Write (*,99995) 'x06ak return value:', x06akf()
          Write (*,99998) 'No. threads in 1st parallel region:', x06abf()
        !$Omp End Master

        ifail = 0
        !$Omp Barrier
        Call x06aaf(inner_threads,ifail)

        !$Omp Parallel Shared (total_3,inner_num), Default (None)

!         Get max number of threads inside second active parallel region
          inner_num = x06abf()

          !$Omp Atomic
            total_3 = total_3 + 1
          !$Omp End Atomic

        !$Omp End Parallel

        !$Omp Master
          Write (*,99998) 'No. threads in 2nd parallel region:', inner_num
        !$Omp End Master

      !$Omp End Parallel

      Write (*,99999) 'Total threads:', total_3

99999 Format (4X,A,I35)
99998 Format (4X,A,I14)
99997 Format (1X,A,I11)
99996 Format (4X,A,I24)
99995 Format (4X,A,I30)
    End Program x06ajfe