Fsdb::Filter::dbcolscorrelate(3)

NAME
dbcolscorrelate - find the coefficient of correlation over columns

SYNOPSIS
    dbcolscorrelate column1 column2 [column3...]

DESCRIPTION
Compute the coefficient of correlation over two (or more) columns.

The output is one line of correlations.

With exactly two columns, a new column correlation is created.

With more than two columns, correlations are computed for each pairwise combination of rows, and each output column is given a name which is the concatenation of the two source rows, joined with an underscore.

By default, we compute the population correlation coefficient (usually designed rho, ρ) and assume we see all members of the population. With the --sample option we instead compute the sample correlation coefficient, usually designated r. (Be careful in that the default here to full-population is the opposite of the default in dbcolstats.)

This program requires a complete copy of the input data on disk.

OPTIONS

--sample
    Select a the Pearson product-moment correlation coefficient (the "sample correlation coefficient", usually designated r).

--nosample
    Select a the Pearson product-moment correlation coefficient (the "sample correlation coefficient", usually designated r).

-f FORMAT or --format FORMAT
    Specify a printf(3)-style format for output statistics. Defaults to "%.5g".

-T TmpDir
    where to put tmp files. Also uses environment variable TMPDIR, if -T is not specified. Default is /tmp.

This module also supports the standard fsdb options:

-d  Enable debugging output.

-i or --input InputSource
    Read from InputSource, typically a file name, or "-" for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

-o or --output OutputDestination
    Write to OutputDestination, typically a file name, or "-" for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

--autorun or --noautorun
    By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The "--(no)autorun" option controls that behavior within Perl.

--help
    Show help.

--man
    Show full manual.

SAMPLE USAGE

  Input:
    #fsdb name id test1 test2
    a 1 80 81
    b 2 70 71
    c 3 65 66
    d 4 90 91
    e 5 70 71
    f 6 90 91

  Command:
    cat DATA/more_grades.fsdb | dbcolscorrelate test1 test2

  Output:
    #fsdb correlation
    0.83329
    #  | dbcolscorrelate test1 test2

SEE ALSO
Fsdb, dbcolstatscores, dbcolsregression.

CLASS FUNCTIONS

  new
    $filter = new Fsdb::Filter::dbcolscorrelate(@arguments);

Create a new dbcolscorrelate object, taking command-line arguments.

  set_defaults
    $filter->set_defaults();

Internal: set up defaults.

  parse_options
    $filter->parse_options(@ARGV);

Internal: parse command-line arguments.

  setup
    $filter->setup();

Internal: setup, parse headers.

  run
    $filter->run();

Internal: run over each rows.

AUTHOR and COPYRIGHT
Copyright (C) 1991-2018 by John Heidemann <johnh@isi.edu>

This program is distributed under terms of the GNU general public license, version 2. See the file COPYING with the distribution for details.