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<<  Port Validation in HP (formerly Compaq) Tru64, http://bb.cgd.ucar.edu//viewtopic.php?t=77 >>

PostereatonPostedMon Dec 13, 2004 4:48 pm MST, http://bb.cgd.ucar.edu//viewtopic.php?p=242#242
Message: The WACCM model is not currently a supported product (at least not by CSEG), though it may be in the future.
<br />
<br />I have never tried the perturbation growth tests in WACCM and would be amazed if the test worked.  As mentioned in the instructions for running the tests, CAM contains the CPP macro PERGRO which is used to modify algorithms that don't behave well in the perturbation test.  This work has not been carried out for WACCM.  The only way to validate the WACCM model is to do a climate simulation.
<br />
<br />We are not currently testing CAM on a Tru64 machine since we don't have access to one.  I'd suggest that a successful port validation of CAM on your machine would be a good sign that WACCM has been ported successfully as well.  But again, a full climate simulation is the final validation.

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PostersunnyabcPostedTue Dec 14, 2004 2:28 am MST, http://bb.cgd.ucar.edu//viewtopic.php?p=245#245
Message: Thanks for answers. 
<br />
<br />The pertrubation growth test in WACCM seems to work somehow, although
<br />I commented out one line [qm1(...) = dqv(...)] within CPP PERGRO in 
<br />vertical_diffusion.F90 in both the AIX and Tru64 machine.
<br />
<br />I agree with you. The port should be validated using a full climate
<br />simulation using WACCM. Nonetheless, I think, some criteria to ensure 
<br />the validity of the port is still needed in case of using the full climate 
<br />simulation.
<br />
<br />For example, even though climatology (e.g., 20-yr mean) obtained from a
<br />Tru64 machine is consistent with that obtained from a AIX machine, 
<br />temporal behavior of field variables might not be so consistent with each
<br />other, which results in inconsistent phase or amplitude. 
<br />In this case, is this port valid?
<br />
<br />Criteria of a valid port is somewhat unclear to me.
<br />
<br />Essentially, does a valid port mean almost identical resul!
 ts that are 
<br />different only at a few trailing digits?
<br />Or, does even a valid port admit differences of results?

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PostereatonPostedTue Dec 14, 2004 3:49 pm MST, http://bb.cgd.ucar.edu//viewtopic.php?p=246#246
Message: &gt; I agree with you. The port should be validated using a full climate
<br />&gt; simulation using WACCM. Nonetheless, I think, some criteria to ensure
<br />&gt; the validity of the port is still needed in case of using the full climate
<br />&gt; simulation.
<br />
<br />I believe the criteria to validate that two 20 year simulations are samples
<br />from the same climate is an open research question (and possibly not a well
<br />posed one).  In practice one focuses on comparing those aspects of the
<br />climate simulations that are of particular interest.
<br />
<br />The value of the perturbation growth test is that it provides a simple way
<br />to compare two simulations that are expected to differ only due to the
<br />growth of machine roundoff size differences.  This validation is extremely
<br />useful for catching obvious problems with the port, before beginning the
<br />much more difficult and expensive process of running long simulations and
<br /!
 >doing a full climate validation using appropriate scientific criteria.

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