FUNCTION alloc_pd_vars (nrot_yrs, nperiods)

    USE pd_var_type_def
    USE pd_dates_vars
    USE pd_update_vars
    USE pd_report_vars

    USE pd_var_tables

    IMPLICIT NONE

    INTEGER :: alloc_pd_vars            ! Allocate status return
    INTEGER, INTENT (IN) :: nrot_yrs    ! Number of rotation years
    INTEGER, INTENT (IN) :: nperiods    ! Number of total periods

    INTRINSIC ASSOCIATED                ! use to verify status of pointers

    INTEGER :: i, j, m, y               ! Local loop variables

    INTEGER :: alloc_status = 0         ! Local allocate status return
    INTEGER :: ret_status = 0           ! Local allocate status return

    alloc_pd_vars = 0                   ! Init return value to zero


! Allocate for "update" variables
    ALLOCATE (yrly_update(Max_yrly_vars), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating yrly_update(Max_yrly_vars)"
        ret_status = ret_status + alloc_status
    END IF

    ALLOCATE (monthly_update(Max_monthly_vars), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating monthly_update(Max_monthly_vars)"
        ret_status = ret_status + alloc_status
    END IF

    ALLOCATE (hmonth_update(Max_hmonth_vars), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating hmonth_update(Max_hmonth_vars)"
        ret_status = ret_status + alloc_status
    END IF

    ALLOCATE (period_update(Min_period_vars:Max_period_vars), &
              STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, &
          "Error allocating period_update(Min_period_vars:Max_period_vars)"
        ret_status = ret_status + alloc_status
    END IF

! Allocate for all "report" variables
    ALLOCATE (yrly_report(Max_yrly_vars,0:nrot_yrs), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating yrly_report(Max_yrly_vars,0:nrot_yrs)"
        ret_status = ret_status + alloc_status
    END IF
    ALLOCATE (monthly_report(Max_monthly_vars,1:12,0:nrot_yrs), &
       STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, &
          "Error allocating monthly_report(Max_monthly_vars,1:12,0:nrot_yrs)"
        ret_status = ret_status + alloc_status
    END IF
    ALLOCATE (hmonth_report(Max_hmonth_vars,1:nrot_yrs*24), &
        STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, &
          "Error allocating hmonth_report(Max_hmonth_vars,1:nrot_yrs*24)"
        ret_status = ret_status + alloc_status
    END IF

    ALLOCATE (period_report(Min_period_vars:Max_period_vars,1:nperiods), &
        STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, &
          "Error allocating period_report(Min_period_vars:Max_period_vars,1:nperiods)"
        ret_status = ret_status + alloc_status
    END IF

! Allocate for reporting period dates
    ALLOCATE (yrly_dates(0:nrot_yrs), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating yrly_dates(0:nrot_yrs)"
        ret_status = ret_status + alloc_status
    END IF
    ALLOCATE (monthly_dates(1:12,0:nrot_yrs), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating monthly_dates(,1:12,0:nrot_yrs)"
        ret_status = ret_status + alloc_status
    END IF
    ALLOCATE (hmonth_dates(1:nrot_yrs*24), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating hmonth_dates(1:nrot_yrs*24)"
        ret_status = ret_status + alloc_status
    END IF
    ALLOCATE (period_dates(1:nperiods), STAT = alloc_status) 
    IF (alloc_status /= 0) THEN
        print *, "Error allocating period_dates(1:nperiods)"
        ret_status = ret_status + alloc_status
    END IF



! Associate "dates" pointers in "report" variable structures
    do i=1, Max_yrly_vars
      do y=0, nrot_yrs
        yrly_report(i,y)%date => yrly_dates(y)
      end do
      do m=1, 12 !for each month
        do y=0, nrot_yrs
        monthly_report(i,m,y)%date => monthly_dates(m,y)
        end do
      end do
    end do

    do i=1, Max_hmonth_vars
      do j=1, nrot_yrs*24
        hmonth_report(i,j)%date => hmonth_dates(j)
      end do
    end do

    do i=Min_period_vars, Max_period_vars
      do j=1, nperiods
        period_report(i,j)%date => period_dates(j)
      end do
    end do

!  print *, "Max_yrly_vars: ", Max_yrly_vars
!  do y=0, nrot_yrs
!    IF (ASSOCIATED (yrly_report(Wind_energy,y)%date)) THEN
!        print *, "alloc: %date is associated"
!    ELSE
!        print *, "alloc: %date is NOT associated"
!    END IF
!    print *, "alloc: ", yrly_report(Wind_energy,y)%date
!  end do


! Associate "pd_dates" pointers in "pd_update" structures
! (initially point to first "pd_report_dates" for each var)

    DO i=1, Max_yrly_vars
        yrly_update(i)%date => yrly_dates(0)         ! Use yrly dates
        monthly_update(i)%date => monthly_dates(1,0) ! 1st mon of 1st yr dates
    END DO

    DO i=1, Max_hmonth_vars
        hmonth_update(i)%date => hmonth_dates(1)     ! 1st half month period
    END DO

    DO i=Min_period_vars, Max_period_vars
        period_update(i)%date => period_dates(1)     ! 1st period of rotation
    END DO


    alloc_pd_vars = ret_status

END FUNCTION alloc_pd_vars