Hello again. I was mistaken... I was accidently testing with 10^6 points and not 10^7 points. That extra order of magnitude causes a crash in ROOT with the following message: *** BREAK *** write on a pipe with no one to read it Error in <RootX11IOErrorHandler>: fatal X11 error (connection to server lost?) *** Save data and exit application *** So I did a little testing with how many points it would work with. If I have 1048570 (or fewer) data points, everything works fine. If I have 1048571 data points, the graph is displayed fine, but I get the following message: Error in <RootX11ErrorHandler>: BadMatch (invalid parameter attributes) (XID: 37750999, XREQ: 42) If I have 1048572 data points, the border/axes of the graph are displayed fine, but there is no plot of the data, and I get the following message: Error in <RootX11ErrorHandler>: BadLength (poly request too large or internal Xlib length error) (XID: 0, XREQ: 65) If I have 1048573 (or more) data points, ROOT crashes and I get the same error message as for 10^7 points. This failure limit is suspiciously close to 2^20 (1048576). Anyone else successful at plotting more than 2^20 data points? In case you don't have the original email that started this thread... I am using TGraph for plotting the x,y data points. +------------------------------------------------+ | Tony Colley ITT Industries A/CD | | Modeling/Simulation Group Fort Wayne, IN USA | +------------------------------------------------+ | Using ROOT 3.03/02 on RedHat Linux 7.2 | | Last CVS update: 26 Feb 2002 at 2218 GMT | +------------------------------------------------+ -----Original Message----- From: Faine, Valeri [mailto:fine@bnl.gov] Sent: Saturday, March 02, 2002 21:06 To: 'Eddy Offermann '; 'Tony.Colley@itt.com ' Cc: 'roottalk@pcroot.cern.ch ' Subject: RE: [ROOT] Event handling or graphing huge datasets Hello Eddy, I am not sure you correct. It is true "TGraph::PaintGrapHist" does take in account the screen resolution but ExecuteEvent. see: http://root.cern.ch/root/htmldoc/src/TGraph.cxx.html#TGraph:ExecuteEvent When one tries to move the graph (may be accidently, just the wrong mouse button was pressed) this entails the graph of the all fNpoints to be redrawn at least twice: The first time to clear the old graph position and the second time to draw it at the new place. Each of 10^7 points is drawn with 6 calls to TVirtualX::DrawLine sending at list 4 coordinate numbers as an X11-message. This means just one touched (occasionally) the middle button of the mouse the (4*2) * 2 * 6 * 10^7 bytes will be sent out to X-terminal. I believe this may shock the networking. Assuming we have 10Mbit / sec network one can calculate that 10^10 / 10 ^7 = 1000 sec per single mouse step (this assumes the X-terminal response time is as fast as its networking connection) -----Original Message----- From: Eddy Offermann To: Tony.Colley@itt.com Cc: roottalk@pcroot.cern.ch Sent: 2/26/02 12:46 PM Subject: Re: [ROOT] Event handling or graphing huge datasets Hi Tony, Take a look at "void TGraph::PaintGrapHist" and scan for "lowRes". You will see around line 2350 that if you draw the graph with option L or P, The number of data points is checked versus your screen resolution. In case of many data points it will not draw every point but just calculate the average pixel position. 10^7 should not be a problem Eddy A.J.M. Offermann Renaissance Technologies Corp. Route 25A, East Setauket NY 11733 e-mail: eddy@rentec.com http://www.rentec.com --- END OF INCLUDED MESSAGES --- \I'm not responsible for anything below this line/ ************************************ If this email is not intended for you, or you are not responsible for the delivery of this message to the addressee, please note that this message may contain ITT Privileged/Proprietary Information. In such a case, you may not copy or deliver this message to anyone. You should destroy this message and kindly notify the sender by reply email. Information contained in this message that does not relate to the business of ITT is neither endorsed by nor attributable to ITT. ************************************
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