.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.13.
.TH GBACORR "1" "June 2021" "gbacorr 6.2" "User Commands"
.SH NAME
gbacorr \- Compute auto/cross-correlation coefficients
.SH SYNOPSIS
.B gbacorr
[\fI\,options\/\fR]
.SH DESCRIPTION
Compute auto/cross\-correlation coefficients
.PP
If the input is a single columns x_1...X_T, the autocorrelation function
c(t) is printed, defined as
.IP
c_{t} = 1/(T\-t\-1) \esum_i (x_i\-m) (x_{i+t}\-m) /s^2
.PP
where m is the sample average and s the standard deviation.
With a second column y_1...y_T, the cross\-correlation
.IP
c_{t} = 1/(T\-t\-1) \esum_i (x_i\-mx) (y_{i+t}\-my) /(sx sy)
.PP
is printed where mx and my are the average values of the two columns and sx
and sy their standard deviations. With \fB\-M\fR 1 it is mx=my=0, the st.dev. is
computed accordingly and in the previous formula T\-t\-1 is replaced by T\-t.
The range of t is set by option \fB\-t\fR.
Options
.TP
\fB\-M\fR
choose the method (default '0'):
.TP
0
auto/cross\-correlation with mean removal,
.TP
1
auto/cross\-correlation without mean removal
.TP
\fB\-t\fR
set range of t (default '0,10'), accept negative integers
.TP
\fB\-p\fR
specify the confidence level in (0,1). Interval ac_low,ac_hi has a
probability 1\-confidence to contain the true value. With this option
the output becomes: lag ac ac_low ac_hi.
.TP
\fB\-F\fR
specify the input fields separators (default " \et")
.TP
\fB\-h\fR
this help
.SH EXAMPLES
.TP
gbacorr \-t 0,2 'file(1)'
first three a.c. coeff. of the first data column
.TP
gbacorr \-p 0.05 'file(1:2)' x\-corr of the first two columns together with
their 5% confidence intervals
.SH AUTHOR
Written by Giulio Bottazzi
.SH "REPORTING BUGS"
Report bugs to <gbutils@googlegroups.com>
.PP
.br
Package home page <http://cafim.sssup.it/~giulio/software/gbutils/index.html>
.SH COPYRIGHT
Copyright \(co 2001\-2018 Giulio Bottazzi
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
(version 2) as published by the Free Software Foundation;
.PP
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.