Segmentation violation in icethd_do.F90 with nn_hls=2

[acc]

Context

The latest trunk is giving me segmentation violations with WED025 and nn_hls=2. The problem line is setting the heat content in this loop:

         ! Heat content
         DO ji = 1, npti
            jl = jcat(ji)                                                    ! categroy in which new ice is put
            zswinew  (ji) = MAX( 0._wp , SIGN( 1._wp , - za_b(ji,jl) ) )   ! 0 if old ice
         END DO

seemingly because jcat is ill-defined. jcat is set earlier in this loop:

         DO jl = 1, jpl
            DO ji = 1, npti
               IF( zh_newice(ji) > hi_max(jl-1) .AND. zh_newice(ji) <= hi_max(jl) ) THEN
                  a_i_2d(ji,jl) = a_i_2d(ji,jl) + za_newice(ji)
                  v_i_2d(ji,jl) = v_i_2d(ji,jl) + zv_newice(ji)
                  jcat(ji) = jl
               ENDIF
            END DO
         END DO

which doesn't guarantee to set jcat for all npti.

Analysis

Setting jcat=0 before this loop avoids the segmentation fault but risks an out-of-bounds on za_b

Recommendation

Ask an expert

[clem]

jcat should actually be defined for all npti.
The IF condition is fullfilled for one and only one jl but for all npti locations since zh_newice (i.e. ht_i_new) is defined as non-zero everywhere qlead<0

Mmmmh, the problem comes from this loop?

         DO_2D( 0, 0, 0, 0 )
            IF ( qlead(ji,jj) < 0._wp ) THEN ! cooling
...
               ht_i_new(ji,jj) = MAX( 0.01_wp, MIN( ht_i_new(ji,jj), hi_max(jpl) ) )
            ENDIF
         END_2D
         CALL lbc_lnk( 'icethd_do', zvrel, 'T', 1.0_wp, ht_i_new, 'T', 1.0_wp  )

If qlead is > 0 in the haloes maybe? Is it possible? There may be a problem with the lbc_lnk?

Setting ln_frazil to false should work at least

[acc]

Still stuck with this one. Clem is right in that the problem seems to be that qlead is zero everywhere EXCEPT in the haloes which means ht_i_new is not set in the loop he identifies. I've yet to trace a cause.

[acc]

Yay. Clem's changes at changeset:15053 have restored WED025 with nn_hls=2. This ticket can be closed.