EQUATIONS: Completely rewrite this module.

Now, module EQUATIONS provides a complet interface for equation systems,
including the definition of the number of equations/independent
variables, variable indices and names, conversion subroutines between
primitive and conservative variables, flux and characteristic speed
calculation, and maximum speed determination.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>

src/driver.F90

@@ -37,7 +37,7 @@ program amun
   use blocks        , only : initialize_blocks, finalize_blocks, get_nleafs
   use boundaries    , only : initialize_boundaries
   use coordinates   , only : initialize_coordinates, finalize_coordinates
-  use equations     , only : initialize_equations
+  use equations     , only : initialize_equations, finalize_equations
   use evolution     , only : initialize_evolution, advance
   use evolution     , only : n, t, dt, dtn, cfl
 #ifdef FORCE
@@ -225,29 +225,13 @@ program amun
 !
   iterm = 0
 
-! print configuration information
+! initialize module EQUATIONS
 !
-  if (master) then
+  call initialize_equations(master, iret)
 
-    write (*,"(1x,a)"         ) "Physics:"
-    write (*,"(4x,a,1x,a)"    ) "equations              =",                    &
-#ifdef HYDRO
-    "HD"
-#endif /* HYDRO */
-#ifdef MHD
-    "MHD"
-#endif /* MHD */
-    write (*,"(4x,a,1x,a)"    ) "equation of state      =",                    &
-#ifdef ADI
-    "adiabatic"
-#endif /* ADI */
-#ifdef ISO
-    "isothermal"
-#endif /* ISO */
-    write (*,"(4x,a,1x,a)"    ) "geometry               =",                    &
-    "rectangular"
-
-  end if
+! jump to the end if the equations could not be initialized
+!
+  if (iret > 0) go to 30
 
 ! check if the domain is periodic
 !
@@ -309,10 +293,6 @@ program amun
 !
   call initialize_interpolations()
 
-! initialize module EQUATIONS
-!
-  call initialize_equations()
-
 ! initialize boundaries
 !
   call initialize_boundaries()
@@ -716,6 +696,14 @@ program amun
 
   end if
 
+! finalize module EQUATIONS
+!
+  call finalize_equations(iret)
+
+! jump point
+!
+  30 continue
+
 ! finalize parameters
 !
   call finalize_parameters()

src/evolution.F90

@@ -426,7 +426,7 @@ module evolution
 
 ! include external procedures
 !
-    use equations     , only : maxspeed
+    use equations     , only : maxspeed, cmax, cmax2
 #ifdef MPI
     use mpitools      , only : reduce_maximum_real, reduce_maximum_integer
 #endif /* MPI */
@@ -436,7 +436,6 @@ module evolution
     use blocks        , only : block_data, list_data
     use coordinates   , only : adx, ady, adz
     use coordinates   , only : toplev
-    use variables     , only : cmax
 
 ! local variables are not implicit by default
 !
@@ -494,6 +493,10 @@ module evolution
     call reduce_maximum_integer(lev , iret)
 #endif /* MPI */
 
+! calculate squared cmax
+!
+    cmax2 = cmax * cmax
+
 ! find the smallest spatial step
 !
 #if NDIMS == 2

src/schemes.F90

@@ -1072,7 +1072,7 @@ module schemes
 
 ! include external procedures
 !
-    use equations     , only : prim2cons, fluxspeed
+    use equations     , only : prim2cons, fluxspeed, cmax
     use interpolations, only : reconstruct
 #ifdef FIX_POSITIVITY
     use interpolations, only : fix_positivity
@@ -1088,7 +1088,6 @@ module schemes
     use variables     , only : ibx, iby, ibz
 #ifdef GLM
     use variables     , only : iph
-    use variables     , only : cmax
 #endif /* GLM */
 
 ! local variables are not implicit by default

src/variables.F90

@@ -55,10 +55,6 @@ module variables
 #endif /* MHD */
   integer(kind=4), parameter :: nvr = nqt
   integer(kind=4), parameter :: nt  = nqt
-
-! the maximum characteristic speed in the domain
-!
-  real           , save      :: cmax = 0.0d+0
 !
 !===============================================================================
 !