Useful Tools: Difference between revisions

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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.

~~''''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~~:

==== 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

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Line 202:

$ 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:

@@ Line 163: / Line 163: @@
 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.
-''''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:
+==== 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
@@ Line 189: / Line 202: @@
   $ echo $?
+''''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: