/[MITgcm]/MITgcm/pkg/mnc/README.txt
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Revision 1.13 - (hide annotations) (download)
Wed Mar 24 15:29:33 2004 UTC (22 years, 5 months ago) by edhill
Branch: MAIN
CVS Tags: checkpoint57o_post, checkpoint52n_post, checkpoint53d_post, checkpoint54a_pre, checkpoint57m_post, checkpoint55c_post, checkpoint54e_post, checkpoint54a_post, checkpoint53c_post, checkpoint57k_post, checkpoint55d_pre, checkpoint57d_post, checkpoint57g_post, checkpoint57b_post, checkpoint57c_pre, checkpoint55j_post, checkpoint56b_post, checkpoint57i_post, checkpoint57e_post, checkpoint55h_post, checkpoint57g_pre, checkpoint54b_post, checkpoint53b_pre, checkpoint55b_post, checkpoint54d_post, checkpoint56c_post, checkpoint52m_post, checkpoint55, checkpoint53a_post, checkpoint57f_pre, checkpoint57a_post, checkpoint54, checkpoint54f_post, checkpoint53b_post, checkpoint55g_post, checkpoint55f_post, checkpoint57r_post, checkpoint57a_pre, checkpoint55i_post, checkpoint57, checkpoint56, checkpoint53, eckpoint57e_pre, checkpoint57h_done, checkpoint53g_post, checkpoint57n_post, checkpoint57p_post, checkpoint57f_post, checkpoint57q_post, checkpoint57c_post, checkpoint55e_post, checkpoint53f_post, checkpoint55a_post, checkpoint53d_pre, checkpoint54c_post, checkpoint57j_post, checkpoint57h_pre, checkpoint57l_post, checkpoint57h_post, checkpoint56a_post, checkpoint55d_post
Changes since 1.12: +5 -4 lines
File MIME type: text/plain 
 o in the MNC_CW_xxx_[R|W]_yyy calls, move the yyy=[R|D|I] part to
     a string variable within the argument list so that the output
     types are now run-time selectable
 o fix a bug in the initialization order -- ini_mnc_io() must be called
     after grid initialization
1 edhill 1.1
2 edhill 1.2 API Discussions:
3     ================
4    
5 edhill 1.1 As discussed in our group meeting of 2003-12-17 (AJA, CNH, JMC, AM,
6     PH, EH3), the NetCDF interface should resemble the following FORTRAN
7     subroutines:
8    
9     1) "stubs" of the form: MNC_WV_[G|L]2D_R[S|L] ()
10    
11 edhill 1.8 2) MNC_INIT_VGRID('V_GRID_TYPE', nx, ny, nz, zc, zg)
12 edhill 1.1
13 edhill 1.8 3) MNC_INIT_HGRID('H_GRID_TYPE', nx, ny, xc, yc, xg, yg)
14 edhill 1.1
15 edhill 1.8 4) MNC_INIT_VAR('file', 'Vname', 'Vunits', 'H_GTYPE', 'V_GTYPE', PREC, FillVal)
16 edhill 1.1
17 edhill 1.8 5) MNC_WRITE_VAR('file', 'Vname', var, bi, bj, myThid)
18 edhill 1.1
19     This is a reasonable start but its inflexible since it isn't easily
20     generalized to grids with dimensions other than [2,3,4] or grids with
21     non-horizontal orientations (eg. vertical slices).
22    
23    
24     Generalizing what we would like to write as "variables defined on 1-D
25     to n-D grids", one can imagine a small number of objects containing
26     all the relevant information:
27    
28     a dimension: [ name, size, units ]
29     a grid: [ name, 1+ dim-ref ]
30     a variable: [ name, units, *1* grid-ref, data ]
31     an attribute: [ name, units, data ]
32     a NetCDF file: [ name, 0+ attr, 0+ grid-ref, 0+ var-ref ]
33    
34     which can then be manipulated (created, associated, destroyed, etc.)
35     using a simple interface such as:
36    
37 edhill 1.8 MNC_INIT( myThid )
38 edhill 1.1
39 edhill 1.12 MNC_FILE_CREATE( fname, myThid )
40     MNC_FILE_OPEN( fname, itype, myThid )
41     MNC_FILE_ADD_ATTR_STR( fname, atname, sval, myThid )
42     MNC_FILE_ADD_ATTR_DBL( fname, atname, len, dval, myThid )
43     MNC_FILE_ADD_ATTR_REAL(fname, atname, len, rval, myThid )
44     MNC_FILE_ADD_ATTR_INT( fname, atname, len, ival, myThid )
45     MNC_FILE_ADD_ATTR_ANY( fname, atname, atype, cs,len,dv,rv,iv, myThid )
46 edhill 1.1 ...
47 edhill 1.12 MNC_FILE_READ_HEADER( fname, myThid )
48 edhill 1.1
49 edhill 1.12 MNC_DIM_INIT( fname, dname, dlen, myThid )
50 edhill 1.1
51 edhill 1.12 MNC_GRID_INIT( fname, gname, ndim, dnames, myThid )
52 edhill 1.1
53 edhill 1.12 MNC_VAR_INIT_DBL( fname, gname, vname, units, myThid )
54     MNC_VAR_INIT_REAL( fname, gname, vname, units, myThid )
55     MNC_VAR_INIT_INT( fname, gname, vname, units, myThid )
56     MNC_VAR_INIT_ANY( fname, gname, vname, units, type, myThid )
57     MNC_VAR_ADD_ATTR_STR( fname, vname, atname, sval, myThid )
58     MNC_VAR_ADD_ATTR_DBL( fname, vname, atname, nv, dval, myThid )
59     MNC_VAR_ADD_ATTR_REAL( fname, vname, atname, nv, rval, myThid )
60     MNC_VAR_ADD_ATTR_INT( fname, vname, atname, nv, ival, myThid )
61     MNC_VAR_ADD_ATTR_ANY( fname, vname, atname, atype, cs,len,dv,rv,iv, myThid )
62     MNC_VAR_WRITE_DBL( fname, vname, var, myThid )
63     MNC_VAR_WRITE_REAL( fname, vname, var, myThid )
64     MNC_VAR_WRITE_INT( fname, vname, var, myThid )
65     MNC_VAR_WRITE_ANY( fname, vname, vtype, dv, rv, iv, myThid )
66 edhill 1.1 ...
67 edhill 1.12 MNC_VAR_READ( fname, vname, var, myThid )
68 edhill 1.1
69 edhill 1.12 MNC_FILE_SYNC( fname, myThid )
70     MNC_FILE_CLOSE( fname, myThid )
71 edhill 1.8
72    
73     Heres a further "convenience wrapper" written on top of the above UI:
74    
75 edhill 1.12 MNC_CW_INIT( Gtype, Htype, Hsub, Vtype, Ttype, wHalo, myThid )
76 edhill 1.8
77 edhill 1.9 with pre-defined - xy - - n
78     combinations: U x c t y
79     'Cen_xy_c_t_Hn' V y i
80     'U_xy_i_t_Hn', Cen
81     'Cor_x_-_-_Hy' Cor
82 edhill 1.8
83 edhill 1.13 MNC_CW_SET_UDIM( fbname, udim, myThid )
84 edhill 1.1
85 edhill 1.13 MNC_CW_RX_W( 'R|D|I', fbname,bi,bj, vtype, indu, var, myThid )
86     MNC_CW_RX_R( 'R|D|I', fbname,bi,bj, vtype, indu, var, myThid )
87     |
88     +-- RX = 'RL', 'RS', or 'I'
89 edhill 1.11
90 edhill 1.12 MNC_COMP_VTYPE_VAR( ind_vt, ind_fv_ids, ires, myThid )
91 edhill 1.2
92    
93     To-Do:
94     ======
95    
96 edhill 1.7 1) NAMING -- We should (as much as possible) try to name variables so
97     that they are in agreement with the CF naming conventions.
98    
99     2) UNITS -- as with the names we need to follow conventions
100 edhill 1.6
101 edhill 1.7 3) AM described her "diags" (or "myDiags" or "mDiags") interface
102 edhill 1.6 which should use MNC for output. The data storage idea is similar
103     to the MNC tables-of-indicies approach but also includes one huge
104     double-precision "accumulator" to hold all the temporary values
105     (eg. partial sums for averages, current max/mins):
106    
107     vname ( ni )
108     vlen ( ni )
109 edhill 1.7 vind ( ni ) ------+
110 edhill 1.8 |
111 edhill 1.6
112     vij_diag ( i, j, [...] ) w/ lat/lon indicies
113     vgl_diag ( [...] ) wo/ lat/lon indicies (global)
114 edhill 1.7
115     4) CNH pointed out that grid interpolation needs to be handled
116     "on-the-fly" since pre-processing would result in overly large
117     input files. We need an interpolation API...
118 edhill 1.8
119     5) From the group meeting on 2004/01/21, we need to define
120     "sub-grids" corresponding to:
121    
122     var_name HGRID VGRID TIME
123     ===========================================
124     u U_xy r_c t
125     eta T_xy - t
126     rac T_xy - -
127    
128     And write a convenience wrapper so that users can write variables
129     using just two function calls. JMC and I worked out the
130     following:
131    
132 edhill 1.7
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