# GaussianRandomWalk parameters

**URL:** <https://discourse.pymc.io/t/gaussianrandomwalk-parameters/4895>\
**Category:** Questions\
**Created:** [April 19, 2020, 7:28pm UTC](https://discourse.pymc.io/t/gaussianrandomwalk-parameters/4895 "2020-04-19T19:28:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gpoon](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/gpoon/32/2038_2.png) [@gpoon](https://discourse.pymc.io/u/gpoon)\
**Post date:** [April 19, 2020, 7:28pm UTC](https://discourse.pymc.io/t/gaussianrandomwalk-parameters/4895/1 "2020-04-19T19:28:00Z")

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In the timeseries doc page, the GaussianRandomWalk (as well as AR actually) has a sd parameter as well as sigma parameter. How are they different? The docs do not seem to refer to the sd parameter anywhere.

[https://docs.pymc.io/api/distributions/timeseries.html#pymc3.distributions.timeseries.GaussianRandomWalk](https://docs.pymc.io/api/distributions/timeseries.html#pymc3.distributions.timeseries.GaussianRandomWalk)

Thanks for your insight,  
Gregory

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**Author:** ![tirthasheshpatel](https://avatars.discourse-cdn.com/v4/letter/t/ac91a4/32.png) [@tirthasheshpatel](https://discourse.pymc.io/u/tirthasheshpatel)\
**Post date:** [April 19, 2020, 8:18pm UTC](https://discourse.pymc.io/t/gaussianrandomwalk-parameters/4895/2 "2020-04-19T20:18:00Z")

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The `sd` parameter is equivalent to `sigma` parameter but deprecated since pymc3 v3.8. You can specify either of those for now but in future `sd` would be removed.

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**Author:** ![gpoon](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/gpoon/32/2038_2.png) [@gpoon](https://discourse.pymc.io/u/gpoon)\
**Post date:** [April 19, 2020, 8:33pm UTC](https://discourse.pymc.io/t/gaussianrandomwalk-parameters/4895/3 "2020-04-19T20:33:44Z")

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Many thanks for your clarification!