# Global masked summation over domain for 2D array

**URL:** <https://nemo-ocean.discourse.group/t/global-masked-summation-over-domain-for-2d-array/344>\
**Category:** Uncategorized\
**Tags:** DIA\
**Created:** [10 August 2022 15:15 UTC](https://nemo-ocean.discourse.group/t/global-masked-summation-over-domain-for-2d-array/344 "2022-08-10T15:15:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![robinson](https://avatars.discourse-cdn.com/v4/letter/r/848f3c/32.png) [@robinson](https://nemo-ocean.discourse.group/u/robinson)\
**Post date:** [10 August 2022 15:15 UTC](https://nemo-ocean.discourse.group/t/global-masked-summation-over-domain-for-2d-array/344/1 "2022-08-10T15:15:49Z")

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Dear All,

I am trying to code some diagnostic in Nemo, and for that I need to do `mpp_sum` on a 2D array.  
Meaning that `mpp_sum` would need to sum each member i,j of the array separately among all the processors. But I cannot find an example on how to do that, would have any idea ?

Thanks for your help,

Robinson

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**Author:** ![smasson](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@smasson](https://nemo-ocean.discourse.group/u/smasson)\
**Post date:** [18 August 2022 10:14 UTC](https://nemo-ocean.discourse.group/t/global-masked-summation-over-domain-for-2d-array/344/2 "2022-08-18T10:14:40Z")

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You have to use the function `glob_sum` to do that. There is several examples in _src/OCE/DIA/diaar5.F90_. The function itself is coded in _src/OCE/lib\_fortran.F90_ and _src/OCE/lib\_fortran\_generic.h90_.