11.6.1 General Equation Control Variables

The following set of variables are used by the general equation module to determine what to use in the construction of the discretised equation. The variables are all contained in the public include file geneqn.fh and can be set by each solved variable. The following table lists the names of the variables, the default value of the variable and what value the variable should contain

MOD_ID	0	Module identifying integer
VAR_ID	0	Pointer to the current values of the variable being solved
COR_ID	0	Pointer to the correction array of the variable being solved
DACOE_ID	0	Pointer to the array of element based diffusion coefficients
CACOE_ID	0	Pointer to the array of element based convection coefficients
BDY_COEVAL_ID	0	Pointer to the array of boundary patch coefficient-value array.
BDY_BDTYPE_ID	0	Pointer to the array of boundary patch type array.
VOL_COEVAL_ID	0	Pointer to the array of volume source coefficient-value array.
VOL_BDTYPE_ID	0	Pointer to the array of volume source type array.
TCN_ID	0	Pointer to the array of the coefficient of the current time step term
TCO_ID	0	Pointer to the array of the coefficient of the current time step term
FDIFFX_ID	0	Pointer to the face based x gradients of the solved variable
FDIFFY_ID	0	Pointer to the face based y gradients of the solved variable
FDIFFZ_ID	0	Pointer to the face based z gradients of the solved variable
MD_DAFLUX_ID	0	Pointer to the array of multi-domain diffusion fluxes
SUM_AA	0	Pointer to the array to hold the sum of off diagonal values in the system matrix.
VAR_AP	0	Pointer to the array to hold the diagonal value in the system matrix.
DA_TERM	DEFAULT_DIFFUSION	Flag to indicate if the diffusion term is to be used.
CA_TERM	DEFAULT_CONVECTION	Flag to indicate if the convection term is to be used.
DA_MEAN	HARMONIC_MEAN	Flag to indicate is the harmonic mean should be used to calculate face diffusion coefficients
GENEQN_FALSE_DT_VALUE	0.0	False time step value.
GENEQN_LINEAR_RELAX	DEFAULT_LINEAR_RELAX	linear relaxation value
GENEQN_LNORM	DEFAULT_GENEQN_LNORM	Norm to be used to calculate the residual
GENEQN_REF_VALUE	DEFAULT_REF_VALUE	Residual reference value
GENEQN_USER_TERM	DEFAULT_USER_TERM	Are there any extra user defined terms in the equation?
SCHEME_ID	DEFAULT_SCHEME	Which difference scheme should be used
EXPLICIT_VALUE	0.0	Proportion of discretised equation to be calculated using explicit assumptions
EXPLICIT_PART	0	Pointer to array holding explicit contribution.

In the above a 0 value is given to a pointer to indicate it has not been set. If the pointer is not 0 on entry to the general equation module it is assumed that the quantity is not relevant to the current variable. This will usually lead to any associated contributions not being calculated.