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.\" RCSid "$Id: histo.1,v 1.7 2010/07/08 18:54:39 greg Exp $" | 
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.TH HISTO 1 9/6/96 RADIANCE | 
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.SH NAME | 
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histo - compute 1-dimensional histogram of N data columns | 
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.SH SYNOPSIS | 
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1.3 | 
.B "histo [-c][-p] xmin xmax nbins" | 
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1.1 | 
.br | 
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.B "histo [-c][-p] imin imax" | 
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.SH DESCRIPTION | 
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.I Histo | 
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bins columnular data on the standard input between the given minimum | 
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and maximum values. | 
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If three command line arguments are given, the third is taken as the | 
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number of data bins between the first two real numbers. | 
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If only two arguments are given, they are both assumed to be integers, | 
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and the number of data bins will be equal to their difference plus one. | 
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The bins are always of equal size. | 
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.PP | 
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The output is N+1 columns of data (for N columns input), where the | 
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first column is the centroid of each division, and each row | 
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corresponds to the frequencies for each column around that value. | 
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.PP | 
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If the | 
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.I \-c | 
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option is present, then | 
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.I histo | 
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computes the cumulative histogram for each column instead of the | 
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straight frequencies. | 
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The upper value of each bin is printed also instead of the centroid. | 
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This may be useful in computing percentiles, for example. | 
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Values below the minimum specified are still counted in the cumulative | 
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total. | 
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.PP | 
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The | 
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.I \-p | 
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option tells | 
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.I histo | 
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to report the percentage of the total number of input lines rather | 
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than the absolute counts. | 
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In the case of a cumulative total, this yields the percentile values | 
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directly. | 
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Values above the maximum are counted as well as values below in | 
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this case. | 
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.PP | 
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All input data is interpreted as real values, and columns must be | 
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white-space separated. | 
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If any value is less than the minimum or greater than the maximum, | 
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it will be ignored unless the | 
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.I \-c | 
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option is specified. | 
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1.1 | 
.SH EXAMPLE | 
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To count data values between \-1 and 1 in 50 bins: | 
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.IP "" .2i | 
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histo \-1 1 50 < input.dat | 
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.PP | 
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To count frequencies of integers between 0 and 255: | 
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.IP "" .2i | 
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histo 0 255 < input.dat | 
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.SH AUTHOR | 
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Greg Ward | 
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.SH "SEE ALSO" | 
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1.8 | 
cnt(1), neaten(1), rcalc(1), rcollate(1), rlam(1), tabfunc(1), total(1) |