Difference between ProjectionX and ProfileX

Hi,
From documents of TH2, I cannot tell the difference between ProfileX and ProjectionX. Any expert can tell the difference? If they are same, why do we have two same functions?

Zhiyi.

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Hi Zhiyi,

Though I’m not an expert I’ll try to explain. Profile and projection are not the same thing. I attach a pdf with explanation: 2d-histo, its projection and its profile.

2Dhisto_and_proj_and_prof.pdf (98.1 KB)

As you can see ProjectionX makes our histo to “lose” its y-values, so we know only how many X values were in this bin when we were dealing with 2d-histo, and all the information about what were y-values is lost.
And what about profiles: for every X-bin averaged y-value is calculated.

Hope it helps!

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