FDS Source: Allow CVODE_ORDER at the COMB line

Author: cxp484

Source/chem.f90

@@ -928,13 +928,14 @@ SUBROUTINE CVODE_SERIAL(CC,ZZ_0, TMP_IN, TMP_UNMIX, PR_IN, ZETA0, TAU_MIX, CELL_
 END IF
 
 ! SET MAX ORDER
-MAXORD_C = 5
-!IF (IS_EXPONENT_LT_1) MAXORD_C = 1
-IERR_C = FCVODESETMAXORD(CVODE_MEM, MAXORD_C)
-IF (IERR_C /= 0) THEN
-   WRITE(LU_ERR,*) 'ERROR IN FCVODESETMAXORD, IERR = ', IERR_C, '; HALTING'
-   STOP 1
-END IF
+IF (CVODE_ORDER > 0) THEN
+   MAXORD_C = CVODE_ORDER
+   IERR_C = FCVODESETMAXORD(CVODE_MEM, MAXORD_C)
+   IF (IERR_C /= 0) THEN
+      WRITE(LU_ERR,*) 'ERROR IN FCVODESETMAXORD, IERR = ', IERR_C, '; HALTING'
+      STOP 1
+   END IF
+ENDIF
 
 ! SET ERROR HANDLER
 IERR_C = FCVODESETERRHANDLERFN(CVODE_MEM, C_FUNLOC(FDS_CVODE_ERR_HANDLER), C_NULL_PTR)

Source/cons.f90

@@ -905,7 +905,7 @@ MODULE CHEMCONS
 LOGICAL  :: DO_CHEM_LOAD_BALANCE = .FALSE.
 INTEGER  :: MAX_CVODE_SUBSTEPS=100000
 INTEGER  :: CVODE_MAX_TRY=4
-LOGICAL  :: IS_EXPONENT_LT_1 = .FALSE.
+INTEGER  :: CVODE_ORDER=0
 
 ! FOR WRITING CVODE SUBSTEPS
 LOGICAL  :: WRITE_CVODE_SUBSTEPS = .FALSE.

Source/read.f90

@@ -4506,11 +4506,11 @@ END SUBROUTINE PROC_SPEC_2
 !> \brief Read the COMBustion namelist line
 
 SUBROUTINE READ_COMB
-USE CHEMCONS, ONLY: ODE_MIN_ATOL, EQUIV_RATIO_CHECK, MIN_EQUIV_RATIO, MAX_EQUIV_RATIO, DO_CHEM_LOAD_BALANCE, &
+USE CHEMCONS, ONLY: ODE_MIN_ATOL,CVODE_ORDER,EQUIV_RATIO_CHECK, MIN_EQUIV_RATIO, MAX_EQUIV_RATIO, DO_CHEM_LOAD_BALANCE, &
                 FUEL_ID_FOR_AFT,USE_MIXED_ZN_AFT_TMP
 REAL(EB) :: ODE_REL_ERROR
 CHARACTER(LABEL_LENGTH) :: RAMP_ZETA_0='null'
-NAMELIST /COMB/ CHECK_REALIZABILITY,COMPUTE_ADIABATIC_FLAME_TEMPERATURE, DO_CHEM_LOAD_BALANCE, EQUIV_RATIO_CHECK, &
+NAMELIST /COMB/ CHECK_REALIZABILITY,COMPUTE_ADIABATIC_FLAME_TEMPERATURE,CVODE_ORDER,DO_CHEM_LOAD_BALANCE, EQUIV_RATIO_CHECK, &
                 EXTINCTION_MODEL,FINITE_RATE_MIN_TEMP, FIXED_MIX_TIME,FREE_BURN_TEMPERATURE, &
                 FUEL_ID_FOR_AFT,INITIAL_UNMIXED_FRACTION, MAX_CHEMISTRY_SUBSTEPS, MAX_EQUIV_RATIO, MIN_EQUIV_RATIO, &
                 N_FIXED_CHEMISTRY_SUBSTEPS, ODE_MIN_ATOL,ODE_REL_ERROR,ODE_SOLVER,SUPPRESSION,TAU_CHEM, &
@@ -5092,7 +5092,7 @@ END SUBROUTINE READ_REAC
 
 
 SUBROUTINE PROC_REAC_1
-USE CHEMCONS, ONLY: YP2ZZ,IS_EXPONENT_LT_1,FUEL_ID_FOR_AFT,I_FUEL,I_CO2,I_H2O,I_O2,I_N2
+USE CHEMCONS, ONLY: YP2ZZ,FUEL_ID_FOR_AFT,I_FUEL,I_CO2,I_H2O,I_O2,I_N2
 USE PROPERTY_DATA, ONLY : PARSE_EQUATION, SHUTDOWN_ATOM
 REAL(EB) :: MASS_PRODUCT,MASS_REACTANT,REACTION_BALANCE(118),NU_Y(N_SPECIES)
 INTEGER :: NS,NS2, NR
@@ -5315,16 +5315,6 @@ SUBROUTINE PROC_REAC_1
       ENDIF
    ENDDO
 
-   IF(TRIM(ODE_SOLVER)=='CVODE' .AND. .NOT. IS_EXPONENT_LT_1) THEN
-      DO NS=1,RN%N_SPEC
-         IF (RN%N_S(NS) .LT. 1) THEN
-            IS_EXPONENT_LT_1 = .TRUE.
-            !IF (MY_RANK==0) WRITE(LU_ERR,'(A)')"INFO: CVODE solver order set to 1 because one REAC has an N_S < 1."
-            EXIT
-         ENDIF
-      ENDDO
-   ENDIF
-
    ! Normalize the stoichiometric coefficients by that of the fuel.
    RN%NU_FUEL_0 = -RN%NU(RN%FUEL_SMIX_INDEX)
    RN%NU_NN = RN%NU