# Fast Physics

**URL:** <https://cms-helpdesk.ncas.ac.uk/t/fast-physics/1375>\
**Category:** Uncategorized\
**Created:** [22 March 2024 09:24 UTC](https://cms-helpdesk.ncas.ac.uk/t/fast-physics/1375 "2024-03-22T09:24:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![hannahbryant](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@hannahbryant](https://cms-helpdesk.ncas.ac.uk/u/hannahbryant)\
**Post date:** [22 March 2024 09:24 UTC](https://cms-helpdesk.ncas.ac.uk/t/fast-physics/1375/1 "2024-03-22T09:24:55Z")

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Hi!

I have a NaN in some of my model results (just in the reaction fluxes and the depositions in 2 months of the year, at the same gridcell every time). I have found that switching the print diagnostic output from ‘extra’ to ‘normal’ gets rid of this NaN but it has been suggested to me that this could be indicative of a different problem. Also, the model runs fine, it is just that the NaN is present in the output.

The only mention of NaN in the pe\_output is in this part of the code:  
Fast physics sources for ENDGame from atmos\_physics2:

min max average (non-bit reproducing (1=has NaN 0= no NaN)

s\_u : -0.5564579735829906E+01 0.5802499317287101E+01 0.1589033852216605E-02 0.0000000000000000E+00

s\_v : -0.8444975193034946E+01 0.5780337396182014E+01 0.1867734409725696E-02 0.0000000000000000E+00

s\_w : 0.0000000000000000E+00 0.0000000000000000E+00 0.0000000000000000E+00 0.0000000000000000E+00

s\_thetav : -0.6033176751342552E+01 0.5222628785879749E+01 0.6732461536329830E-02 0.0000000000000000E+00

s\_m\_v : -0.2867714156057954E-02 0.4943025615899429E-02 0.7890842180805032E-06 0.0000000000000000E+00

s\_m\_cl : -0.5100833351312710E-03 0.7124591886542622E-03 -0.1587211086800438E-07 0.0000000000000000E+00

s\_m\_cf : -0.2160993887597663E-03 0.3359977660962913E-03 0.1637545710665547E-06 0.0000000000000000E+00

s\_m\_rain : -0.5828132731526547E-05 0.3544967582433885E-05 -0.1496926075626854E-09 0.0000000000000000E+00

I wondered if this 1= has NaN is what is causing the issue? When the print statement is not extra this section of the pe\_output is not printed.

Thanks,  
Hannah