Histo-Scope and NPlot - Interactive Histogramming and Plotting Tools


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Abstract

Histo-Scope is a tool to select and display histograms, n-tuples, and scalar values from a program as data is being created or analyzed. Using Histo- Scope, physicists can interactively "browse" through the large quantities of statistical data that their analysis and data acquisition programs gather as they run. It is intended to complement existing physics applications, providing immediate access to data while a program is running, as well as new interactive methods for viewing data.

Histo-Scope has two parts. The first is a small library of routines which can be in serted in physics analysis or data acquisition code without significantly changing its be havior. The other part is the "scope" process. Invoked upon user demand, the scope re quests and displays data continu ously from the analysis process. The scope concentrates on interacting effectively with users. It responds to mouse and key board input and provides the interactive graphing and plotting that enable users to view their data quickly and effectively. The scope program, on its own, can read HBOOK and Histo-Scope format files.

NPlot is a tool for quickly plotting columnar data from text files. It is a simple re-packaging of the Histo-Scope n-tuple interface with a file reader.

Both Histo-Scope and NPlot produce highly interactive graphs and plots. These include: multi-variable graphs, two and three dimensional scatter plots, one and two dimensional histograms, and a number of specialty plots such as adaptive histograms and cell plots. Users can re-scale, zoom, and pan these plots by dragging on axis scales and other sensitive areas. The three dimensional widgets, 2D histogram and 3D scatter plot, can be rotated accurately using the mouse as a hand on a "virtual track ball" sphere surrounding the plot. The plots can also be combined with animation sliders to reflect additional variables or to re-bin histograms.

The newest version Histo-Scope includes an enhanced application programming interface for working with n-tuple and histogram data independent of HBOOK, as well as methods for setting variables and activating routines within the connected executable.

Histo-Scope is available in executable form for IRIX, AIX, Ultrix, OSF/1, and Solaris by anonymous ftp to ftp.fnal.gov, in the /pub/histo/[ver] directory. For further information, see the Histo-Scope User's Guide, also available from the Fermilab Computing Division Library (Wilson Hall, 8th floor, NE corner). Send questions or comments to histoscope_support@fnal.gov.


histoscope_support@fnal.gov
October 12, 2000