_ROOT Version:6.18/00

*Platform:* x86_64-centos7-gcc8-opt

*Compiler:* gcc8

Dear all,

Here is a minimal non working example of the issue:

In [3]: h1 = np.array([1,2,3])

In [4]: h2 = np.array([4,5,6])

In [5]: from array import array

In [6]: h = r.TH2D(“h”, “h”, len(h1) -1, array(‘d’, h1), len(h2) -1, array(‘d’, h2))

In [7]: h.Draw()

In [8]: h.GetBinContent(10)

Out[8]: 0.0

As you can see, the TH2 is empty.

This little test was done using Python 2.7.16

This used to work in previous ROOT versions. It was even possible to build the TH2 using numpy arrays (without transforming them to C-like arrays).

If I try to use plain numpy arrays:

In [5]: h1 = np.array([1,2,3,4])

In [6]: h2 = np.array([10,20,30,40])

In [7]: h = r.TH2D(“h”, “h”, len(h1) -1, h1, len(h2) -1, h2)

In [8]: h.Draw()

Info in TCanvas::MakeDefCanvas: created default TCanvas with name c1

In [9]: Error in TCanvas::Range: illegal world coordinates range: x1=0.000000, y1=0.000000, x2=0.000000, y2=0.000000

Error in TCanvas::RangeAxis: illegal axis coordinates range: xmin=0.000000, ymin=0.000000, xmax=0.000000, ymax=0.000000`

Thx,

Fabrice