The configure utility creates the header files misc.h, params.h, and preproc.h and the directory search path file Filepath. These files are written to the directory given by the -cam_bld argument of configure (the default is the directory from which configure is executed). It is not necessary to edit these files to produce supported CAM configurations as that can be easily accomplished by the configure utility. However, a user experimenting with non-standard configurations may need to edit these files directly. Thus, the file contents are summarized below. The use of these files by gmake is also discussed below in the section "Details of gmake procedure".
|COUP_CSM||Define if the flux-coupled ocean configuration
will be used.
COUP_CSM is always undefined for stand-alone mode.
|PERGRO||Define if you want to make error growth tests
with your model simulation. This token turns off parts of the prognostic
cloud water parameterization so that the error growth happens at a reasonable
Default setting is with PERGRO undefined.
|USEFFTLIB||Define if you want to use a intrinsic FFT
package rather than the ECMWF FFT package provided with the code in the
Default setting is USEFFTLIB undefined.
|SPMD||Enables the distributed memory (SPMD) implementation.|
|STAGGERED||Enables staggered grid processing. Required for use with the Lin-Rood dynamical core, otherwise undefined.|
|PCNST||Number of advected constituents including
water vapor and cloud-water.
Default setting is 1 (for water vapor).
|PNATS||Number of non-advected constituents.
Default setting is 1 (for cloud water).
|PLEV||Number of vertical levels.
Default setting is 26.
|PLEVR||Number of vertical levels over which radiation calculations are performed. Use of separate vertical coordinate for the radiation calculation has not been tested. Therefore this directive must currently be set to the same value as PLEV.|
|PLON||Number of longitudes on the transform grid.
Default setting is 128.
|PLAT||Number of Gaussian latitudes on the CAM2.0
Default setting is 64.
|PCOLS||Maximum number of columns to use for the
physics. This value can be tuned for different computer architectures
in order to increase performance.
Default setting is 16.
|PTRM||Spectral truncation of the zonal wavenumber
Default setting is 42.
|PTRN||Spectral truncation of the total wavenumber
for zonal wavenumber 0.
Default setting is 42.
|PTRK||Maximum total wavenumber k, for
any zonal wavenumber m.
Default setting is 42.
|COUP_CAM||Tell the CLM that it is being run as a subroutine beneath the atmospheric model.|
|LSMLON||Number of longitudes for the landmodel grid. Currently this directive must have the same value as PLON in params.h.|
|LSMLAT||Number of latitudes for the land-model grid. Currently this directive must have the same value as PLAT in params.h.|
cpp directives of the form #include, #if defined, etc., are used to enhance portability, and allow for the implementation of distinct blocks of platform-specific code within a single file. Header files, such as misc.h, are included with #include statements within the source code. When gmake is invoked, the C preprocessor includes or excludes blocks of code depending on which cpp tokens have been defined. cpp directives are also used to perform textual substitution for resolution-specific parameters in the code. The format of these cpp tokens follows standard cpp protocol in that they are all uppercase versions of the Fortran variables, which they define. Thus, a code statement like
parameter(plat = PLAT)
will result in the following processed line (for standard T42 resolution).
parameter(plat = 64)
gmake invokes the utility mkSrcfiles to generate a list of source files (written to the file Srcfiles) using each directory listed in Filepath. gmake then invokes the utility mkDepends to create a dependency file (written to the file Depends) in the CAM build directory. If a file listed as a dependency does not exist in the CAM build directory, gmake searches the directories contained in Filepath, in the order given, for a file with that name. The first file found satisfies the dependency. If user-modified code is to be introduced, Filepath should contain, as the first entry (or entries), the directory containing the user code. User code directories are specified with the -usr_src option to configure.
A parallel gmake is achieved in the build scripts by using gmake with the -j option, which specifies the number of jobs (commands) to run simultaneously.
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