<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Dear experts,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I would like to fill a 2D histogram in Rivet's analyze() function, which I then turn into a 1D histogram during finalize(). This would be done by iterating along the x-axis and calculating y_bin[0] / (y_bin[0] + y_bin[1]). It's basically an efficiency histogram, but there doesn't seem to be an existing class that can handle this natively. However, naively using bookHisto2D and Histo2DPtr analogously to Histo1D doesn't work: these types don't seem to exist.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">How would you suggest I go about making the histogram that I need using Rivet 2?</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Thanks,<br>James</div></div>