## SYNOPSIS

**gbfun**[

*options*]

*<function definition>*...

## DESCRIPTION

Compute arbitrary colum-wise functions on data read from standard input. Variable 'xi' stands for the i-th column while 'x0' stands for the row number, e.g. a function f(x1,x2) operates on the first and secod column. With the option**-t**the function is computed, in turn, on every column. In this case f(x1,x2) stands for a function of the column itself and of the following column (the index being a lead operator). In these cases 'x' is equivalent to 'x1'. With

**-r**or

**-R**the function is recursevely computed "columwise" on each row. In this case the variable 'x' identifies the result of the previous evaluation. A lag operator can be specified with the letter l, like in 'x1l2', which means the first column two steps before. More functions can be specified and will be considered in turn.

## OPTIONS

**-t**- compute on each column
**-r**- set initial value and compute recursively
**-R**- set initial value, compute recursively and print intermediary results
**-v**- verbose mode
**-F**- specify the input fields separators (default " \t")
**-o**- set the output format (default '%12.6e')
**-s**- set the output separation string (default ' ')
**-h**- this help

## EXAMPLES

- gbfun 'x0+log(x2)' file
- print the log of the second column of 'file' adding the progressive number of the row
- gbfun -r 0 'x+sqrt(x1)' file
- print the sum of the square root of the elements of the first column of 'file'

## AUTHOR

Written by Giulio Bottazzi## REPORTING BUGS

Report bugs to <[email protected]>

Package home page <http://cafim.sssup.it/~giulio/software/gbutils/index.html>

## COPYRIGHT

Copyright © 2001-2015 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;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.