Creating a large histogram with tree splitting

[dave]

I was talking about the 1073741822 byte limit.

But I just came across the following post.
So hopefully THnSparse is the answer.

Creating TH3 larger than 810x810x810

Hello this is my first time posting to Root Support, I hope I’m following all the rules. My issue is that I want to build big 3 dimensional arrays. But, void cubeBuild() { TFile *File = new TFile(“cubeTest.root”,“RECREATE”); int nRange = 100; int nBins = 811; TH3S f(“h3”, “h3”, nBins, 0, nRange, nBins, 0, nRange, nBins, 0, nRange); File->Write(); } Causes: Error in TBufferFile::WriteByteCount: bytecount too large (more than 1073741822) But when nBins = 810 or lower there is no Error. …

Thanks