(divcurlB) if required, densityiterate is called twice, computing dif…

…ferent things each time

build/Makefile

@@ -1785,7 +1785,7 @@ SOURCES= physcon.f90 ${CONFIG} ${SRCKERNEL} io.F90 units.f90 boundary.f90 \
          mpi_dens.F90 mpi_force.F90 stack.F90 mpi_derivs.F90 kdtree.F90 linklist_kdtree.F90 ${SRCTURB} \
          ${SRCPHOTO} ${SRCINJECT} ${SRCKROME} memory.F90 ${SRCREADWRITE_DUMPS}  \
          quitdump.f90 ptmass.F90 \
-         readwrite_infile.F90 dens.F90 mhd_divcurlB.F90 force.F90 utils_deriv.f90 deriv.F90 energies.F90 sort_particles.F90 \
+         readwrite_infile.F90 dens.F90 force.F90 utils_deriv.f90 deriv.F90 energies.F90 sort_particles.F90 \
          evwrite.F90 step_leapfrog.F90 writeheader.F90 ${SRCAN} step_supertimestep.F90 mf_write.f90 evolve.F90 \
          checksetup.F90 initial.F90
 

src/main/config.F90

@@ -226,10 +226,13 @@ module dim
  integer :: maxmhd = 0
 #ifdef MHD
  logical, parameter :: mhd = .true.
+ logical, parameter :: fast_divcurlB      = .false. ! true/false: will calculate divcurlB in/after densityiterate permitting/preventing a race condition
 #else
  logical, parameter :: mhd = .false.
+ logical, parameter :: fast_divcurlB      = .true.  ! do not toggle; multiple calculations controlled by this flag, and this is faster when excluding MHD
 #endif
- logical, parameter :: mhd_racecondition = .false. ! true/false: will calculate divcurlB in/after densityiterate permitting/preventing a race condition
+ logical            :: calculate_density  = .true.  ! do not toggle; initialised for efficiency
+ logical            :: calculate_divcurlB = .true.  ! do not toggle; initialised for efficiency
  integer, parameter :: maxBevol  = 4  ! size of B-arrays (Bx,By,Bz,psi)
  integer, parameter :: ndivcurlB = 4