# gp-2.9 man page

gp — The PARI calculator

## Synopsis

**gp** [**-s** *stacksize*] [**-p** *primelimit*] [**--emacs**] [**-f**|**--fast**] [**-q**|**--quiet**] [**-D**|**--default** *key=val*] [**--help**] [**--test**] [**--texmacs**] [**--version**] [**--version-short**] [ file1 file2 ...]

## Description

Invokes the PARI-GP calculator **gp**; gp is an advanced programmable calculator, specializing in number theory, which computes symbolically as long as possible, numerically where needed, and contains a wealth of arithmetic functions: factorizations, elliptic curves, Galois theory, class field theory... Commands, written in the GP scripting language, are input interactively or loaded from files.

If present at the end of the command line, files 'file1', 'file2', ... are loaded on startup; they must be written in the GP language.

## Options

Command line options are available in both short form (-f) and POSIX-like (--fast). Numeric arguments can be followed by a modifier **k** , **M** or **G** at the user's convenience; in that case the argument is multiplied by 10^3, 10^6, or 10^9 respectively.

**-f, --fast**Fast start (or factory settings). Do not read

**.gprc**(see below) upon startup.**-p limit**[DEPRECATED] Upon startup, gp computes a table of small primes used in number-theoretic applications. If

*primelimit*is set, the table include primes up to that bound instead of the default (= 500000). It is now mostly useless to change this value.**-q, --quiet**Quiet mode. Do not print headers or history numbers and do not say goodbye.

**-D, --default key=val**performs

**default(key, val)**; on startup, overriding values from the**gprc**preferences file. 'val' must be a constant value and is not allowed to involve any computation (e.g. 1+1 is forbidden). Any number of such default-setting statements may appear on the command line.**-s limit**Size of gp internal stack allocated on startup. When gp runs out of space, it interrupts the current computation and raises a

**stack overflow**exception. If this occurs frequently, start with a bigger stack. The stack size can also be increased from within gp, using**default(parisize,**limit)**;**it may be convenient to set**stacksize**from your**.gprc.**Note that computations with a**smaller**stack may be more efficient due to better data locality. Most computations should need less than 20MB.**--emacs**gp can be run in an

*Emacs*shell (see GP User's manual for details). This flag is then required for smooth interaction with the*PariEmacs*package (pari.el). It is set automatically by the pari.el package, and will produce nice display oddities if you set it outside of an*Emacs*session.**--help**print a summary of available command-line options.

**--test**run gp in test mode: suppress printing of history numbers and wrap long output lines (to get readable diff output). For benches only.

**--texmacs**gp can be run from a

*TeXmacs*frontend. This flag is set by TeXmacs, to enable special purpose communication channels. Do not set it yourself.**--version**output version info (banner) then exit.

**--version-short**output version number then exit.

## Use

**?**to get online help.

**??**to get extended online help (more precisely, to call the external help program,

**gphelp**by default)**quit**(or \q), or

**EOF**(Ctrl-D) to quit**gp**.

The following works only when gp was linked with GNU *readline* library:

- arrow keys
for editing and viewing the input history.

**TAB**for automatic completion

## Manuals

The following material is included in the standard distribution (originally in TeX format):

*The User's Guide to PARI/GP*(users.dvi)

*The User's Guide to the PARI library*(library.dvi)

*The Developer's Guide to the PARI library*(develop.dvi)

*PARI/GP, a tutorial*(tutorial.dvi)

*PARI/GP reference card*(refcard.ps): 4 pages, based on an earlier version by Joseph H. Silverman.

## Files

*gp*main executable

*$HOME/.gprc*(or $GPRC if set) user preference file, read at beginning of execution by each

**gp**shell. A default gprc*gprc.dft*is provided with the distribution. If this file cannot be found,*/etc/gprc*is checked instead.*pari.log*default logfile (can be changed in the gprc file or interactively using

**default()**)*pari.ps*default psfile used for postscript output (as above)

*gphelp*default external help program (as above)

**.gp*GP programs

## Environment

*$GPRC*place to look for the user's preference file (gprc); if the file does not exist, we then check in $HOME/.gprc, /etc/gprc, and finally for a file named 'gprc' in PARI's

**datadir.***$GP_DATA_DIR*directory containing data installed by optional PARI packages. For example, the Galois resolvents files in directory

*galdata/*needed by the**polgalois**function, in degrees 8 to 11; or the modular polynomials in*seadata/*used by the**ellap**function for large base fields. This environment variable overrides PARI's 'datadir', defined at Configure time.*$GP_POSTSCRIPT_VIEWER*an application able to display PostScript files, used by the

*plotps*graphic engine. This engine is a fallback used to output hi-res plots even when no compatible graphical library was available on your platform at Configure time. (Dumps the graph to a temporary file, then open the file.)*$GPHELP*name of the external help program invoked by ?? and ??? shortcuts.

*$GPTMPDIR*name of the directory where temporary files will be generated.

## Home Page

PARI's home page resides at

## Mailing Lists

There are a number of mailing lists devoted to the PARI/GP package, and most feedback should be directed to those. See

for details. The most important ones are:

- **pari-announce** (moderated): for us to announce major version changes.

- **pari-dev:** for everything related to the development of PARI, including suggestions, technical questions, bug reports or patch submissions.

- **pari-users:** for discuss about everything else, in particular ask for help.

To subscribe, send empty messages with a Subject: containing the word "subscribe" respectively to

pari-announce-request@pari.math.u-bordeaux.fr

pari-users-request@pari.math.u-bordeaux.fr

pari-dev-request@pari.math.u-bordeaux.fr

## Bug Reports

Bugs should be submitted online to our Bug Tracking System, available from PARI's home page, or directly from the URL

Further instructions can be found on that page.

## Trivia

Despite the leading G, GP has nothing to do with GNU. The first version was originally called GPC, for Great Programmable Calculator. For some reason, the trailing C was eventually dropped.

PARI has nothing to do with the French capital. The name is a pun about the project's early stages when the authors started to implement a library for "Pascal ARIthmetic" in the PASCAL programming language. They quickly switched to C.

For the benefit of non-native French speakers, here's a slightly expanded explanation: **Blaise Pascal** (1623-1662) was a famous French mathematician and philosopher who was one of the founders of probability and devised one of the first "arithmetic machines". He once proposed the following "proof" of the existence of God for the unbelievers: whether He exists or not I lose nothing by believing in Him, whereas if He does and I misbehave... This is the so-called "pari de Pascal" (Pascal's Wager).

Note that PARI also means "fairy" in Persian.

## Authors

PARI was originally written by Christian Batut, Dominique Bernardi, Henri Cohen, and Michel Olivier in Laboratoire A2X (Universite Bordeaux I, France), and was maintained by Henri Cohen up to version 1.39.15 (1995), and by Karim Belabas since then.

A great number of people have contributed to the successive improvements which eventually resulted in the present version. See the AUTHORS file in the distribution.

## See Also

gap(1), gphelp(1), perl(1), readline(3), *sage*(1), tex(1), texmacs(1),

## Copying

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License 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.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.