hprod.C: Histogram producer script. This script creates a memory mapped
{
// Histogram producer script. This script creates a memory mapped
// file and stores three histogram objects in it (a TH1F, a TH2F and a
// TProfile). It then fills, in an infinite loop (so use ctrl-c to
// stop this script), the three histogram objects with random numbers.
// Every 10 fills the objects are updated in shared memory.
// Use the hcons.C script to map this file and display the histograms.
//Author: Fons Rademakers
gROOT->Reset();
// Create a new memory mapped file. The memory mapped file can be
// opened in an other process on the same machine and the objects
// stored in it can be accessed.
TMapFile::SetMapAddress(0xb46a5000);
mfile = TMapFile::Create("hsimple.map","RECREATE", 1000000,
"Demo memory mapped file with histograms");
// Create a 1d, a 2d and a profile histogram. These objects will
// be automatically added to the current directory, i.e. mfile.
hpx = new TH1F("hpx","This is the px distribution",100,-4,4);
hpxpy = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
hprof = new TProfile("hprof","Profile of pz versus px",100,-4,4,0,20);
// Set a fill color for the TH1F
hpx->SetFillColor(48);
// Print status of mapped file
mfile->Print();
// Endless loop filling histograms with random numbers
Float_t px, py, pz;
int ii = 0;
while (1) {
gRandom->Rannor(px,py);
pz = px*px + py*py;
hpx->Fill(px);
hpxpy->Fill(px,py);
hprof->Fill(px,pz);
if (!(ii % 10)) {
mfile->Update(); // updates all objects in shared memory
if (!ii) mfile->ls(); // print contents of mapped file after
} // first update
ii++;
}
}
Last change: Wed Dec 17 10:56:31 2008
Last generated: 2008-12-17 10:56
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