2D plot draw command using 2 1D histograms

[nab]

Hi,

I have two 1D histograms in a macro. I want to make a 2D histogram using these 1D histograms by taking h1 on the x-axis and h2 on the y-axis.
How would I do this.

[couet]

Your question is not very clear.
I guess you want the X and Y axis of the 2D histograms equal to h1 Axis et H2 X axis.
You have all the getters in the TH1 class to retrieve these values …
But then what a out the bin contents ? …

[Axel]

You can not do that. Start with the values (x|y) = (0, 1), (1,1), (0, 1). In your head, fill two 1D histograms, and then try to create the 2D histogram that corresponds to the original values and you’ll see why

Axel.

[ksmith]

I posted an example of two different 2D histograms that produce similar 1D histograms, demonstrating that this is not possible. I thought it might be relevant / educational here.

Rebinning of 2D ROOT histogram in Python

This is still not possible. For example, you cannot know if the low values of x correspond to the low values of y, or the high values (slope positive or negative). Having the two distributions does provide some information about what situations can be excluded, but will not provide a single relation between x and y. Take this example: { TH2D* h2d_A = new TH2D("h2d_A","Dist A", 100, -2, 2, 100, -2, 2); TH2D* h2d_B = new TH2D("h2d_B","Dist B", 100, -2, 2, 100, -2, 2); for (int i=0;i<5…