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HIST

HIST

## Purpose

Compute histogram and corresponding x values. Allows weights.

## Calling Sequence

h = hist(a, [x, bin])

## Inputs

a = input array. in
bin = optional bin size. in
Def is a size to give about 30 bins.
NBINS over-rides bin value and returns value used.

## Keywords

MINH=mn sets min histogram value.
MAXH=mx sets max histogram value.
/EXACT means use MINH and MAXH exactly. Else
adjusts so histogram goes to 0 at ends.
/BIN_START means return x as bin start values,
else x is returned as bin mid values.
MAXBINS = mx. Set max allowed number of bins to mx.
Over-rides default max of 1000.
NBINS = n. Set number of bins used to about n.
Actual bin size is a nice number giving about n bins.
Over-rides any specified bin size.
WEIGHT=wt Array of weights for each input array element.
If this is given then the weights are summed for each
bin instead of the counts. Returned histogram is a
floating array. Slower.

## Outputs

x = optionally returned array of x values. out
h = resulting histogram. out

## Notes

Notes: the boundaries of the histogram bins are positioned
as follows: [...,-2*bin,-bin,0,bin,2*bin,...].
To be compatable with plot,x,h,psym=10 the returned x
array has values at the bin centers, that is:
[...,-2.5*bin,-1.5*bin,-.5*bin,.5*bin,1.5*bin,...].
This may be over-ridden using the /BIN_START keyword
which returns the X array with the bin starting X instead
of the bin center.

## Modification History

R. Sterner. Converted to SUN 11 Dec, 1989.
R. Sterner. Added MINH, MAXH, EXACT, and BIN_START, 14 Aug, 1991.
R. Sterner. Fixed integer overflow problem for bin size. 2 Oct, 1992.
R. Sterner. Added weighted histogram. 1994 Jan 27.
M. R. Keller. Fixed integer/float problem for binsize test. 27 Jan 2003.
R. Sterner, 2010 Jul 13 --- Converted arrays from () to [].
Copyright (C) 1989, Johns Hopkins University/Applied Physics Laboratory
This software may be used, copied, or redistributed as long as it is not
sold and this copyright notice is reproduced on each copy made. This
routine is provided as is without any express or implied warranties
whatsoever. Other limitations apply as described in the file disclaimer.txt.

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