Name

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      AUTOHIST

Purpose

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      Draw a histogram using automatic bin-sizing.

Explanation

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      AUTOHIST chooses a number of bins (initially, SQRT(2*N). If this leads
      to a histogram in which > 1/5 of the central 50% of the bins are empty,
      it decreases the number of bins and tries again. The minimum # bins is
      5. The max=199. Called by HISTOGAUSS and HALFAGAUSS.

Calling Sequence

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      AUTOHIST, Sample, XLines, Ylines, XCenters, YCenters, [/NOPLOT, ]
                            ...Plotting Keywords

Input

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      Sample = the vector to be histogrammed

Output

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      XLINES = vector of x coordinates of the points that trace the rectangular
              histogram bins
      YLINES = vector of y coordinates. To draw the histogram plot YLINES vs
                XLINES
      XCENTERS = the x values of the bin centers
      YCENTERS = the corresponding y values

Optional Input Keywords

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      /NOPLOT If set, nothing is drawn
      Any plotting keywords (e.g. XTITLE) may be supplied to AUTOHIST through
      the _EXTRA facility.

Revision History

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      Written, H. Freudenreich, STX, 1/91
      1998 March 17 - Changed shading of histogram. RSH, RSTX
      V5.0 update, _EXTRA keywords W. Landsman April 2002
      Added NOCLIP keyword for POLYFILL call C. Paxson/W. Landsman July 2003
      Use Coyote graphics W. Landsman Feb 2011