Hello,
Hum, sorry, I trusted your use of BOUNDARY_COLOUR but actually there is a mistake here. BOUNDARY_COLOUR is the last number of every line in the boundary conditions file, thus it is the boundary point number, so the line :
IF(BOUNDARY_COLOUR%I(KK).EQ.NBOR(K_DC)) THEN
should be:
IF(BOUNDARY_COLOUR%I(KK).EQ.K_DC) THEN
Please note that your scalar section lacks the -ZF in the HBOR formula, compared to your parallel section.
With best regards,
Jean-Michel Hervouet