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Prescribed aerosols modal treatment produces erroneous random number distributions #246

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singhbalwinder opened this issue Jun 5, 2015 · 0 comments · Fixed by #312
Closed

Prescribed aerosols modal treatment produces erroneous random number distributions #246

singhbalwinder opened this issue Jun 5, 2015 · 0 comments · Fixed by #312
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Atmosphere bug

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@singhbalwinder
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Prescribed aerosol code uses Fortran intrinsic random number generator. There is an algorithm to generate seeds for this random number generator each time it is called. The intention here was to get uniformly distributed random numbers but during our experiments we found the random numbers are not uniformly distributed (due to incorrect seeding).

To fix this problem we are now using KISSVEC random number generator which already exists in CAM. KISSVEC is initialized with 4 predefined seeds and keep on producing uniformly distributed random numbers each time it is invoked. Our tests reveal that using KISSVEC solves the problem we were having with the skewed random number distributions.
singhbalwinder added a commit that referenced this issue Aug 27, 2015
@singhbalwinder
Random number generation fix for the prescribed aerosols in CAM
389d0ae 
This commit fixes the random number generation bug in prescribed
aerosols routine. Please see issue #246 for more details.The fix
make use of KISSVEC random number generator instead of the Fortran
intrinsic.

Fixes #246
[non-BFB]
AG-343
@singhbalwinder singhbalwinder mentioned this issue Aug 27, 2015
Merged
susburrows added a commit that referenced this issue Aug 31, 2015
@susburrows
Merge branch 'singhbalwinder/atm/fix-prescribed-aero-rand-num-gen' in…
77ba425 
…to next (PR #312)

Random number generation fix for the prescribed aerosols in CAM.

This commit fixes the random number generation bug in prescribed
aerosols routine. Please see issue #246 for more details.  The fix
make use of KISSVEC random number generator instead of the Fortran
intrinsic.

This commit passes the acme developer tests. It changes answers only
for the prescribed aerosols run as it is using a new random number
generator.

Fixes #246
[non-BFB]
AG-343
susburrows added a commit that referenced this issue Sep 2, 2015
@susburrows
Merge branch 'singhbalwinder/atm/fix-prescribed-aero-rand-num-gen' (PR …
2f6f92b 
…#312)

Random number generation fix for the prescribed aerosols in CAM

This commit fixes the random number generation bug in prescribed
aerosols routine. Please see issue #246 for more details.The fix
make use of KISSVEC random number generator instead of the Fortran
intrinsic.

This commit passes the acme developer tests. It changes answers only
for the prescribed aerosols run as it is using a new random number
generator.

Fixes #246
[non-BFB]
AG-343
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Random number generation fix for the prescribed aerosols in CAM E3SM-Project/E3SM
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@rljacob @singhbalwinder