initializing gru products to zero in fates runs

doc/ChangeLog

@@ -1,4 +1,78 @@
 ===============================================================
+Tag name: ctsm5.1.dev143
+Originator(s): rgknox (Ryan Knox,LAWRENCE BERKELEY NATIONAL LABORATORY,510-495-)
+Date: Fri Oct 13 08:53:38 MDT 2023
+One-line Summary: Zeroing of wood product fluxes on fates columns
+
+Purpose and description of changes
+----------------------------------
+
+This is a small change that initializes wood product fluxes on fates columns to zero. These
+products are otherwise zero'd in a p2c() routine that is incompatible with fates. When
+wood product fluxes become available via fates, these routines will be updated. These fluxes
+were previously left as uninitialized, which was causing math issues on some compilers.
+
+
+Significant changes to scientifically-supported configurations
+--------------------------------------------------------------
+
+There are no changes to scientifically-supported configurations.
+
+[ ] clm5_1
+
+[ ] clm5_0
+
+[ ] ctsm5_0-nwp
+
+[ ] clm4_5
+
+
+Bugs fixed or introduced
+------------------------
+
+Fixes CTSM issue 2165
+
+
+Notes of particular relevance for users
+---------------------------------------
+
+
+No caveats, no bugs, no issues of relevance.
+
+No noticable timing changes.
+
+
+Notes of particular relevance for developers:
+---------------------------------------------
+
+None
+
+
+Testing summary:
+----------------
+
+  regular tests (aux_clm: https://github.com/ESCOMP/CTSM/wiki/System-Testing-Guide#pre-merge-system-testing):
+
+    cheyenne ---- OK
+    izumi ------- PASS
+
+  Compared against baseline: ctsm5.1.dev142
+
+
+Answer changes
+--------------
+
+Answer changes only on FATES tests, and only on the specific wood product fluxes modified. These values
+are now zeros, instead of being uninitialized. Everything else is b4b.
+
+
+Other details
+-------------
+
+No other details.
+
+===============================================================
+===============================================================
 Tag name: ctsm5.1.dev142
 Originator(s): samrabin (Sam Rabin, UCAR/TSS, samrabin@ucar.edu)
 Date: Tue Sep 19 11:30:22 MDT 2023

doc/ChangeSum

@@ -1,5 +1,6 @@
 Tag                   Who      Date  Summary
 ============================================================================================================================
+    ctsm5.1.dev143   rgknox 10/13/2023 Zeroing of wood product fluxes on fates columns
     ctsm5.1.dev142 samrabin 09/19/2023 Merge 5 bit-for-bit pull requests
     ctsm5.1.dev141   slevis 09/13/2023 Change small snocan to zero
     ctsm5.1.dev140  afoster 09/12/2023 add lai_streams capability for FATES

src/biogeochem/CNProductsMod.F90

@@ -13,6 +13,7 @@ module CNProductsMod
   use clm_time_manager        , only : get_step_size_real
   use SpeciesBaseType         , only : species_base_type
   use PatchType               , only : patch
+  use clm_varctl              , only : use_fates_bgc
   !
   implicit none
   private
@@ -346,6 +347,17 @@ subroutine InitCold(this, bounds)
        this%tot_woodprod_grc(g) = 0._r8
     end do
 
+    ! We don't call the woodproduct fluxes routine if
+    ! no veg patches are active. This is what happens
+    ! when fates is on. Woodproduct fluxes use a p2g
+    ! upscaling for the gru_ pools. Must zero it here then.
+    if(use_fates_bgc)then
+       do g = bounds%begg, bounds%endg
+          this%gru_prod10_gain_grc(g) = 0._r8
+          this%gru_prod100_gain_grc(g) = 0._r8
+       end do
+    end if
+
     ! Need to set these patch-level fluxes to 0 everywhere for the sake of special
     ! landunits (because they don't get set over special landunits in the run loop)
     do p = bounds%begp, bounds%endp
@@ -387,6 +399,7 @@ subroutine Restart(this, bounds, ncid, flag, &
     ! !LOCAL VARIABLES:
     logical :: template_provided
     logical :: readvar
+    integer :: g
 
     character(len=*), parameter :: subname = 'Restart'
     !-----------------------------------------------------------------------
@@ -485,7 +498,20 @@ subroutine Restart(this, bounds, ncid, flag, &
     end if
 
     if (flag == 'read') then
+
+       ! We don't call the woodproduct fluxes routine if
+       ! no veg patches are active. This is what happens
+       ! when fates is on. Woodproduct fluxes use a p2g
+       ! upscaling for the gru_ pools. Must zero it here then.
+       if(use_fates_bgc)then
+          do g = bounds%begg, bounds%endg
+             this%gru_prod10_gain_grc(g) = 0._r8
+             this%gru_prod100_gain_grc(g) = 0._r8
+          end do
+        end if
+
        call this%ComputeSummaryVars(bounds)
+
     end if
 
   end subroutine Restart
@@ -789,6 +815,7 @@ subroutine ComputeProductSummaryVars(this, bounds)
 
        ! fluxes into wood & crop product pools, from landcover change
        this%cropprod1_grc(g) = this%cropprod1_grc(g) + this%dwt_cropprod1_gain_grc(g)*dt
+
        this%prod10_grc(g)    = this%prod10_grc(g)    + this%dwt_prod10_gain_grc(g)*dt
        this%prod100_grc(g)   = this%prod100_grc(g)   + this%dwt_prod100_gain_grc(g)*dt
 
@@ -834,7 +861,7 @@ subroutine ComputeSummaryVars(this, bounds)
        this%tot_woodprod_grc(g) = &
             this%prod10_grc(g) + &
             this%prod100_grc(g)
-
+       
        ! total loss from wood products
        this%tot_woodprod_loss_grc(g) = &
             this%prod10_loss_grc(g) + &