# Set \`emission\` parameter in FUND

**URL:** <https://forum.mimiframework.org/t/set-emission-parameter-in-fund/181>\
**Category:** Uncategorized\
**Created:** [July 7, 2021, 2:12pm UTC](https://forum.mimiframework.org/t/set-emission-parameter-in-fund/181 "2021-07-07T14:12:16Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tammyt123](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/tammyt123/32/81_2.png) [@tammyt123](https://forum.mimiframework.org/u/tammyt123)\
**Post date:** [July 7, 2021, 2:12pm UTC](https://forum.mimiframework.org/t/set-emission-parameter-in-fund/181/1 "2021-07-07T14:12:16Z")

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Hi there,

When I try to use `set_param!` on the `emission` parameter in FUND, it gives me the following error

> ERROR: Cannot set parameter :emission; not found in ModelDef or children

Just wondering why this is the case? When I call m[:emissions, :emission] it does seem to return the variable, and I can see it in the `:emissions` component of the code, so I’m not sure why it’s not letting me set the parameter. Thanks!

(The code I’m running is `set_param!(m, :emission, input_emissions)`)

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**Author:** ![lrennels](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/lrennels/32/6_2.png) [@lrennels](https://forum.mimiframework.org/u/lrennels)\
**Post date:** [July 7, 2021, 4:54pm UTC](https://forum.mimiframework.org/t/set-emission-parameter-in-fund/181/2 "2021-07-07T16:54:06Z")

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Hi Tammy,

I think it looks like `:emission` is a **Variable** in FUND, not a **Parameter** , right? In that case you can’t call `set_param!` on it. Happy to help further if that’s still confusing though or if it makes what you need to do to get your results difficult.

* * *

You can also feel free to start using the new parameter syntax, basically just always using `update_param!` as described [here](https://forum.mimiframework.org/t/psa-better-parameter-api/179) … so in this case if `emission` was a shared parameter, like most FUND parameters are at the moment, you do `update_param!(m, :emission, input_emissions)` or if it was unshared `update_param!(m, :emissions, :emission, input_emissions)` assuming you’ve pulled in the latest versions of FUND and Mimi.

**No pressure on that though** … all of the old syntax still works and no one has gotten around to actually updating the FUND code to use the new syntax ie. decide which parameters should actually be “shared” versus "unshared. You have plenty to do so you don’t have to spend time thinking on this until you have a break, just wanted to let you know! I’lll polish up that part of FUND sometime soon.

Lisa

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**Author:** ![tammyt123](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/tammyt123/32/81_2.png) [@tammyt123](https://forum.mimiframework.org/u/tammyt123)\
**Post date:** [July 7, 2021, 5:24pm UTC](https://forum.mimiframework.org/t/set-emission-parameter-in-fund/181/3 "2021-07-07T17:24:19Z")

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Ohhh, right, sorry – my bad! Yes, that makes sense. Thanks so much! 🙂