Merge pull request #3 from jimmielin/hplin/fixes2

Add note to change -pcols with --append

docs/conversion/run-cam-sima.md

@@ -56,7 +56,7 @@ Once you have successfully run CAM-SIMA and all answer changes have either accep
 
 - Make sure that your snapshot is taken with an updated atmospheric_physics, especially if answers changed during development
 - Check all of your standard_names.  CAM-SIMA will run successfully, but if a standard_name is incorrect, you may be running with an incorrect variation of the variable that you intended
-- If comparing printed values on the physics grid between CAM and CAM-SIMA, then it might be good to turn-off chunking in CAM, which can be done by setting “-pcols” in “CAM_CONFIG_OPTS” to be a large number (e.g. >500 for the ne3 grid).
+- If comparing printed values on the physics grid between CAM and CAM-SIMA, then it might be good to turn-off chunking in CAM, which can be done by setting `-pcols` in `CAM_CONFIG_OPTS` to be a large number (e.g. >500 for the ne3 grid): `./xmlchange CAM_CONFIG_OPTS="-pcols 1352" --append` (use the `--append` option to not lose existing options.)
     - You can also utilize the `tools/find_max_nonzero_index.F90` tool to (more) easily compare values between CAM and CAM-SIMA at a specific rank and index that is known to be non-zero
 - Note that the way latitude in radians is calculated for the null dycore in CAM-SIMA is different (at a round-off level) to the way it is calculated in the SE dycore in CAM.  This means if you are validating a physics scheme that has latitude (in radians) as an input, then in CAM you’ll need to change the scheme interface to read in latitude in degrees, and then convert to radians by multiplying by pi/180 (which you’ll only want to do when creating the snapshot file, not when validating CAM itself).
 - Sometimes CAM-SIMA will set a state variable directly, while CAM will only set a tendency variable and then use the “physics_update” routine to update the state using the tendency.  This can result in round-off level differences.  If this happens then simply try setting the state variable directly in CAM when creating the snapshot files for CAM-SIMA testing.
@@ -66,4 +66,4 @@ Once you have successfully run CAM-SIMA and all answer changes have either accep
     !!! Warning "timestep discrepancy"
         The cam_snapshot file will be written starting with the second timestep, so your **CAM** run will need to advance past the first timestep before you can start comparing.
 
-- If you run into a "tip" that should be added here, please confer with the other CAM SEs to get it added to the documentation!!
+- If you run into a "tip" that should be added here, please confer with the other CAM SEs to get it added to the documentation!!