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C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/GAD_OPTIONS.h,v 1.11 2008/04/23 18:32:20 jahn Exp $ |
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C $Name: $ |
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CBOP |
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C !ROUTINE: GAD_OPTIONS.h |
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C !INTERFACE: |
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C #include "GAD_OPTIONS.h" |
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C !DESCRIPTION: |
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C Contains CPP macros/flags for controlling optional features of package. |
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CEOP |
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C CPP options file for GAD (Generic Advection Diffusion) package |
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C |
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C Use this file for selecting options within the GAD package |
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#ifndef GAD_OPTIONS_H |
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#define GAD_OPTIONS_H |
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#include "PACKAGES_CONFIG.h" |
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#ifdef ALLOW_GENERIC_ADVDIFF |
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#include "CPP_OPTIONS.h" |
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C This flag selects the form of COSINE(lat) scaling of bi-harmonic term. |
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C *only for use on a lat-lon grid* |
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C Setting this flag here only affects the bi-harmonic tracer terms; to |
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C use COSINEMETH_III in the momentum equations set it CPP_OPTIONS.h |
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#define COSINEMETH_III |
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C This selects isotropic scaling of harmonic and bi-harmonic term when |
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C using the COSINE(lat) scaling. |
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C Setting this flag here only affects the tracer diffusion terms; to |
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C use ISOTROPIC_COS_SCALING of the horizontal viscosity terms in the |
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C momentum equations set it CPP_OPTIONS.h; the following line |
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C even overrides setting the flag in CPP_OPTIONS.h |
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#undef ISOTROPIC_COS_SCALING |
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C As of checkpoint41, the inclusion of multi-dimensional advection |
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C introduces excessive recomputation/storage for the adjoint. |
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C We can disable it here using CPP because run-time flags are insufficient. |
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#undef DISABLE_MULTIDIM_ADVECTION |
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C This enable the use of 2nd-Order Moment advection scheme (Prather, 1986) |
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C due to large memory space (10 times more / tracer) requirement, |
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C by default, this part of the code is not compiled. |
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#undef GAD_ALLOW_SOM_ADVECT |
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C Hack to get rid of negatives caused by Redi. Works by restricting the |
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C outgoing flux (only contributions computed in gad_calc_rhs) for each cell |
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C to be no more than the amount of tracer in the cell (see Smolarkiewicz |
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C MWR 1989 and Bott MWR 1989). |
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C The flux contributions computed in gad_calc_rhs which are affected by |
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C this hack are: |
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C - explicit diffusion, Redi and the non-local part of KPP |
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C - advection is affected only if multiDimAdvection=.FALSE. |
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C - vertical diffusion (including the diagonal contribution from GMRedi) |
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C only if implicitDiffusion=.FALSE. |
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C - GM is affected only if GMREDI_AdvForm=.FALSE. |
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C |
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C The parameter SmolarkiewiczMaxFrac (defined in gad_init_fixed.F) |
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C specifies the maximal fraction of tracer that can leave a cell. |
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C By default it is 1. This will prevent the tracer from going negative |
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C due to contributions from gad_calc_rhs alone. In the presence of other |
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C contributions (or roundoff errors), it may be necessary to reduce this |
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C value to achieve strict positivity. |
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C |
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C This hack applies to all tracers except temperature and salinity! |
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C Don't use with Adams-Bashforth (for ptracers)! |
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C Don't use with OBCS! |
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#undef GAD_SMOLARKIEWICZ_HACK |
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#else |
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C If GAD is disabled then so is multi-dimensional advection |
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#define DISABLE_MULTIDIM_ADVECTION |
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#endif /* ALLOW_GENERIC_ADVDIFF */ |
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#endif /* GAD_OPTIONS_H */ |
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