Radiance histo program

HISTO(1)                                                              HISTO(1)

NAME

       histo - compute 1-dimensional histogram of N data columns

SYNOPSIS

       histo [-c][-p] xmin xmax nbins
       histo [-c][-p] imin imax

DESCRIPTION

       Histo bins columnular data on the standard input between the given min-
       imum and maximum values.  If three command line  arguments  are  given,
       the  third  is  taken  as the number of data bins between the first two
       real numbers.  If only two arguments are given, they are  both  assumed
       to be integers, and the number of data bins will be equal to their dif-
       ference plus one.  The bins are always of equal size.

       The output is N+1 columns of data (for  N  columns  input),  where  the
       first column is the centroid of each division, and each row corresponds
       to the frequencies for each column around that value.

       If the -c option is present, then histo computes  the  cumulative  his-
       togram  for each column instead of the straight frequencies.  The upper
       value of each bin is printed also instead of the centroid.  This may be
       useful in computing percentiles, for example.  Values below the minimum
       specified are still counted in the cumulative total.

       The -p option tells histo to report the percentage of the total  number
       of input lines rather than the absolute counts.  In the case of a cumu-
       lative total, this yeilds the percentile values directly.  Values above
       the maximum are counted as well as values below in this case.

       All  input  data  is  interpreted  as  real values, and columns must be
       white-space separated.  If any  value  is  less  than  the  minimum  or
       greater  than  the  maximum, it will be ignored unless the -c option is
       specified.

EXAMPLE

       To count data values between -1 and 1 in 50 bins:

         histo -1 1 50 < input.dat

       To count frequencies of integers between 0 and 255:

         histo 0 255 < input.dat

AUTHOR

       Greg Ward

SEE ALSO

       cnt(1), neaten(1), rcalc(1), rlam(1), tabfunc(1), total(1)

RADIANCE                            9/6/96                            HISTO(1)