GEOS-5

Useful Tools: Difference between revisions

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  CDO is a collection of command line Operators to manipulate and analyse Climate and NWP model Data.  
  CDO is a collection of command line Operators to manipulate and analyse Climate and NWP model Data.  


=== Where to find CDO ===


==== NCCS ====


Possible example uses of CDO are:
Users can access CDO in a variety of ways. On discover, the easiest way is to load the cdo module:


=== Display info about a file ===
module load other/cdo
 
It is also included in GMAO-Baselibs-4_0_0 and higher (corresponds to Ganymed-3_0 or newer). It will be located at
 
$BASEDIR/Linux/bin/cdo
 
once <tt>g5_modules</tt> is sourced.
 
==== NAS ====
 
At NAS, there are a couple options. First, it is available through Baselibs as above. You can also access a portable version (compiled with system gcc) at
 
/nobackup/gmao_SIteam/Utilities/bin/cdo
 
As this is completely portable, you can also copy this to a local <tt>bin</tt> directory if desired.
 
==== GSFC Desktops ====
 
If you are on a GMAO desktop and have access to <tt>/ford1</tt>, there is a version at
 
/ford1/local/EL6-64/bin/cdo
 
as well as at:
 
/ford1/share/gmao_SIteam/Utilities/bin/cdo
 
The <tt>/ford1/share</tt> version could be more bleeding-edge than the <tt>/ford1/local</tt> version as it will usually be whatever version is in the latest Baselibs tag.
 
=== Example Uses of CDO ===
 
==== Display info about a file ====


CDO offers many operators that provide information about a file. The most important two are '''infon''' and '''sinfon'''. Note the '''n''' at the end: that means "display variable names". If you don't provide that, you'll still get information, but it'll be for variables -1, -2, -3, etc.
CDO offers many operators that provide information about a file. The most important two are '''infon''' and '''sinfon'''. Note the '''n''' at the end: that means "display variable names". If you don't provide that, you'll still get information, but it'll be for variables -1, -2, -3, etc.


==== Short Information ====
===== Short Information =====


If you just want a summary of what's in the file, use '''sinfon''':
If you just want a summary of what's in the file, use '''sinfon''':
Line 64: Line 96:
  cdo sinfon: Processed 26 variables over 1 timestep ( 0.02s )
  cdo sinfon: Processed 26 variables over 1 timestep ( 0.02s )


==== Information and Simple Statistics ====
===== Information and Simple Statistics =====


The other operator, '''infon''', provides more information and some useful statistics:
The other operator, '''infon''', provides more information and some useful statistics:
Line 126: Line 158:
As you can see, you not only get information, but statistics. It provides the number of values on the grid, <tt>Gridsize</tt>; the number of Missing Values, <tt>Miss</tt>; and the <tt>Minimum</tt>, <tt>Mean</tt>, and <tt>Maximum</tt> for each <tt>Level</tt> for each value.
As you can see, you not only get information, but statistics. It provides the number of values on the grid, <tt>Gridsize</tt>; the number of Missing Values, <tt>Miss</tt>; and the <tt>Minimum</tt>, <tt>Mean</tt>, and <tt>Maximum</tt> for each <tt>Level</tt> for each value.


=== Diff two files ===
==== Diff two files ====
 
One of the main reasons CDO is attractive is for diffing two files. With binary files, such as the old restarts, one could use <tt>cmp</tt> or <tt>diff</tt> to check for differences. However, <tt>cmp</tt> will not work on NetCDF files because while the data might be the same, the metadata surely won't:
 
$ cmp stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 \
      mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4
stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 \
  mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4 differ: byte 55, line 4


One of the main reasons CDO is attractive is for diffing two files. There already is a tool for doing this with HDF5/NetCDF4 files: <tt>h5diff</tt>. However, <tt>h5diff</tt> is slow (at least the version we have):


  $ time h5diff stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4
There already is a tool for doing this with HDF5/NetCDF4 files: <tt>h5diff</tt>. However, <tt>h5diff</tt> is slow (at least the version we have):
 
  $ time h5diff stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 \
              mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4
  attribute: <Title of </>> and <Title of </>>
  attribute: <Title of </>> and <Title of </>>
  37 differences found
  37 differences found
  0.116u 0.412s 0:44.38 1.1% 0+0k 0+0io 0pf+0w
  0.116u 0.412s '''0:44.38''' 1.1% 0+0k 0+0io 0pf+0w
  $ time cdo diffn stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4
 
CDO, however, seems to be much more efficient at doing diff comparisons:
 
  $ time cdo diffn stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4 \
                  mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4
   0 of 1201 records differ
   0 of 1201 records differ
  cdo diffn: Processed 39344760 values from 52 variables over 2 timesteps ( 0.49s )
  cdo diffn: Processed 39344760 values from 52 variables over 2 timesteps ( 0.49s )
  0.424u 0.068s 0:04.28 11.2% 0+0k 0+0io 0pf+0w
  0.424u 0.068s '''0:04.28''' 11.2% 0+0k 0+0io 0pf+0w


Of course, 44 seconds v 4 seconds isn't much (and with smaller files, GPFS can sometimes 'cache' the files making it seem fast), but with c360, things get inflated. Let's diff two fvcore_internal_rst files:
Of course, 44 seconds v 4 seconds isn't much (and with smaller files, GPFS can sometimes 'cache' the files making it seem fast), but with c360, things get inflated. Let's diff two c360 NetCDF4 fvcore_internal_rst files:


  $ time h5diff fvcore_internal_rst.control.nc4 fvcore_internal_rst.test.nc4
  $ time h5diff fvcore_internal_rst.control.nc4 fvcore_internal_rst.test.nc4
Line 148: Line 193:
  17.125u 1.648s '''2:33.97''' 12.1% 0+0k 0+0io 0pf+0w
  17.125u 1.648s '''2:33.97''' 12.1% 0+0k 0+0io 0pf+0w


=== Extract fields(s) from a file ===
This tells us two things, the <tt>h5diff</tt> we have to use is slow and one should develop at lower-resolution if diffing restarts is part of your process.


==== Extract variable(s) from a file ====
==== Behavior when two files differ ====
 
All the above examples show two files that don't differ. If they do differ, CDO provides additional useful information like:
 
          For each pair of fields the operator prints one line with the following information:
          - Date and Time
          - Level, Gridsize and number of Missing values
          - Occurrence of coefficient pairs with different signs (S)
          - Occurrence of zero values (Z)
          - Maxima of absolute difference of coefficient pairs
          - Maxima of relative difference of non-zero coefficient pairs with equal signs
          - Parameter name
 
as seen here:
 
$ cdo diffn stock-G40U-CPU-2013Jun11-6hour-144.geosgcm_prog.20000415_0000z.nc4 stock-G40U-GPU-2013Jun11-6hour-144.geosgcm_prog.20000415_0000z.nc4
              Date    Time  Level Gridsize    Miss : S Z  Max_Absdiff Max_Reldiff : Parameter name
    1 : 2000-04-15 00:00:00    1000    13104    5606 : F T      0.64627    0.041020 : H         
    2 : 2000-04-15 00:00:00    975    13104    3202 : F F      0.64383    0.19488 : H         
    3 : 2000-04-15 00:00:00    950    13104    2394 : F F      0.64948  0.0014438 : H         
    4 : 2000-04-15 00:00:00    925    13104    2047 : F F      0.65057  0.00083438 : H         
    5 : 2000-04-15 00:00:00    900    13104    1793 : F F      0.67102  0.00067943 : H         
    6 : 2000-04-15 00:00:00    875    13104    1555 : F F      0.66370  0.00058364 : H         
    7 : 2000-04-15 00:00:00    850    13104    1401 : F F      0.65869  0.00043395 : H         
    8 : 2000-04-15 00:00:00    825    13104    1305 : F F      0.64941  0.00036629 : H         
    9 : 2000-04-15 00:00:00    800    13104    1188 : F F      0.63110  0.00033837 : H         
...snip...
  477 : 2000-04-15 00:00:00    0.2    13104      0 : F F    0.019527    0.32925 : V         
  478 : 2000-04-15 00:00:00    0.1    13104      0 : F F    0.059674    0.77863 : V         
  479 : 2000-04-15 00:00:00    0.07    13104      0 : F F    0.057358    0.46071 : V         
  480 : 2000-04-15 00:00:00    0.05    13104      0 : T F    0.021697    0.74741 : V         
  481 : 2000-04-15 00:00:00    0.04    13104      0 : T F    0.021576    0.40354 : V         
  482 : 2000-04-15 00:00:00    0.03    13104      0 : F F    0.020691    0.34921 : V         
  483 : 2000-04-15 00:00:00    0.02    13104      0 : T F    0.020302    0.62736 : V         
  438 of 483 records differ
  389 of 483 records differ more than 0.001
cdo diffn: Processed 12658464 values from 26 variables over 2 timesteps ( 0.17s )
$ echo $?
0
 
''''NOTE'''': CDO returns a status of 0 any time it doesn't encounter an error. Thus, if two files are different, CDO will report differences, but the return status will still be 0 as cdo technically completed successfully as seen above. Thus, any tests you might have that depend on the return of cmp for binary need to be altered for NetCDF4. One possible formulation is:
 
set NUMDIFF = `cdo -s diffn | grep differ | awk '{print $1}'`
if ( $NUMDIFF == 0 ) then
  success
else
  failure
endif
 
==== Extract fields(s) from a file ====
 
===== Extract variable(s) from a file =====


Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables. For example, if you only want CLCN, use '''selname''':
Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables. For example, if you only want CLCN, use '''selname''':
Line 177: Line 273:
  cdo sinfon: Processed 1 variable over 1 timestep ( 0.00s )
  cdo sinfon: Processed 1 variable over 1 timestep ( 0.00s )


==== Extract time(s) from a file ====
===== Extract time(s) from a file =====


To extract a single (or multiple) year from a multi-step file, you can use <tt>selyear</tt>,''year''. For multiple years, you can either do <tt>cdo '''selyear,1999,2000,2001'''</tt> or <tt>cdo '''selyear,1999/2001'''</tt>.
To extract a single (or multiple) year from a multi-step file, you can use <tt>selyear</tt>,''year''. For multiple years, you can either do <tt>cdo '''selyear,1999,2000,2001'''</tt> or <tt>cdo '''selyear,1999/2001'''</tt>.
Line 268: Line 364:
  cdo sinfon: Processed 7 variables over 36 timesteps ( 0.00s )
  cdo sinfon: Processed 7 variables over 36 timesteps ( 0.00s )


==== Other select operators ====
===== Other select operators =====
CDO has many of these operators:
CDO has many of these operators:


Line 296: Line 392:
   selindexbox Select an index box
   selindexbox Select an index box


=== Combining Operators ===
==== Combining Operators ====


Often, you want to do multiple operations on a file. You could, say, do a '''selname''' and output only one variable to a file, then a '''sellevel''' on that new file to select a single level, and then a '''selyear''' on ''that'', etc.:
Often, you want to do multiple operations on a file. You could, say, do a '''selname''' and output only one variable to a file, then a '''sellevel''' on that new file to select a single level, and then a '''selyear''' on ''that'', etc.:
Line 303: Line 399:
  cdo selname: Processed 17926272 values from 7 variables over 2736 timesteps ( 9.60s )
  cdo selname: Processed 17926272 values from 7 variables over 2736 timesteps ( 9.60s )
  $ cdo '''sellevel,1.5''' onlyOX.nc4 onlyOX.only1.5.nc4
  $ cdo '''sellevel,1.5''' onlyOX.nc4 onlyOX.only1.5.nc4
cdo sellevel: Processed 248976 values from 1 variable over 2736 timesteps ( 0.76s )
cdo sellevel: Processed 248976 values from 1 variable over 2736 timesteps ( 0.76s )
  $ cdo '''selyear,1999''' onlyOX.only1.5.nc4 onlyOX.only1.5.only1999.nc4
  $ cdo '''selyear,1999''' onlyOX.only1.5.nc4 onlyOX.only1.5.only1999.nc4
  cdo selyear: Processed 1092 values from 1 variable over 2736 timesteps ( 0.05s )
  cdo selyear: Processed 1092 values from 1 variable over 2736 timesteps ( 0.05s )
Line 377: Line 473:
   0 of 12 records differ
   0 of 12 records differ


== tkcvs ==
== TkCVS ==
 
The main website for TkCVS can be found [http://www.twobarleycorns.net/tkcvs.html here].
 
On discover, you can use TkCVS by loading the <tt>other/tkcvs-8.2.3</tt> module:
 
module load other/tkcvs-8.2.3


== ack ==
== ack ==


The main website for ack can be found [http://beyondgrep.com/ here].
If you'd like to try ack out, you can run:
  curl http://beyondgrep.com/ack-2.04-single-file > ~/bin/ack && chmod 0755 !#:3
and it will install ack for you in your local bin directory.


[[Category:SI Team]]
[[Category:SI Team]]
[[Category:Brown Bags]]
[[Category:Brown Bags]]
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