A Tour of NTL: Obtaining and Installing NTL for UNIX
[Previous] [Up] [Next]

A Tour of NTL: Obtaining and Installing NTL for UNIX

To obtain the source code and documentation for NTL, download ntl-xxx.tar.gz, placing it a directory, and then, working in this directory, do the following. Here, "xxx" denotes the current version number.

Step 1. Extract the source files by executing:

   % gunzip ntl-xxx.tar.gz
   % tar xvf ntl-xxx.tar

Note that this will unpack everything into a sub-directory ntl-xxx, creating this directory if necessary. Next:

   % cd ntl-xxx
   % ls
You should see a file "README", and directories "include", "doc", and "src". The directory "doc" contains all the documentation. The file "doc/tour.html" contains a copy of the on-line documentation. The directory "include" contains all the header files within a subdirectory "include/NTL". The directory "src" contains everything else. Go there now:
   % cd src

Step 2. Run the configuration script.

Execute the command

   % ./configure [ variable=value ]...
This configure script generates the file "makefile" and the file "../include/NTL/config.h", based upon the values assigned to the variables on the command line.

Here are the most important variables, and their default values.

   CC=gcc               # The C compiler
   CXX=g++              # The C++ compiler
   CFLAGS=-O2           # C complilation flags
   CXXFLAGS=$(CFLAGS)   # C++ compilation flags (by default, same as CFLAGS)

   PREFIX=/usr/local    # Directory in which to install NTL library components

   NTL_STD_CXX=off      # ISO Mode switch

   NTL_GMP_LIP=off      # Switch 'on' to enable the use of GMP as the primary
                        # long integer package
   NTL_GMP_HACK=off     # Switch 'on' to enable the use of GMP as a supplemental
                        # long integer package

   GMP_PREFIX=none      # Directory in which GMP components have been installed


There are a number of more esoteric configuration variables that can be set. See config.txt for a complete description.

Note that all of these configuration options can also be set by editing the two files makefile and ../include/NTL/def_config.h by hand. These files are fairly simple and well documented, and so this is not too hard to do.

Note that the file "../include/NTL/def_config.h" contains a backup copy of the original config.h file, and that the file "def_makefile" contains a backup copy of the original makefile file.

This command is intended only as a convenience and -- more importantly -- to allow the configuration process to be script driven. This script does not perform any "magic", like finding out what the local C compiler is called, etc. If the defaults are not correct for your platform, you have to set an appropriate variable.

Step 3. Execute make.

Just type:

   % make

The build process after this point is fully automatic. But here is a description of what happens.

  1. The makefile builds the file "../include/NTL/mach_desc.h", which defines some machine characteristics such as word size and machine precision. This is done by compiling and running a C program called MakeDesc that figures out these characteristics on its own, and prints some diagnostics to the terminal.

  2. A script is run that "automagically" determines the best way to write a timing function on your platform. It tries different routines in the files GetTime1.c, GetTime2.c, etc., and when it finds a good one, it copies the file into GetTime.c.

  3. The files "lip_gmp_aux_impl.h" and "../include/NTL/gmp_aux.h" are generated for use with GMP. If not using GMP, these files are still created, but they are empty.

  4. The configuration wizard script is run. This script works in a sub-directory, compiling several programs, and performing a number of timing experiments, in order to determine the optimal setting for a number of flags in the file ../include/NTL/config.h. When the script finishes (it may take several minutes), you will be told what the wizard thinks are the best settings, and your config.h file will be automatically updated. Note that any flags you set in Step 2 will be in effect while the wizard runs, and will be retained in the updated config.h file, with the exception of the flags
    which are set by the wizard. Also note that if you do not want the wizard to run, you should pass WIZARD=off to the configure script; however, this is not recommended.

  5. The makefile will compile all the source files, and then creates the library "ntl.a" in the current directory.

Note that for finer control you can optionally break up this process into the five component steps:

   % make setup1
   % make setup2
   % make setup3
   % make setup4
   % make ntl.a

After NTL is built.

Executing make check runs a series of timing and test programs. It is a good idea to run this to see if everything really went well.

Executing make install copies a number of files to a directory <prefix> that you specify by passing PREFIX=<prefix> as an argument to configure at configuration time, or as an argument to make install at installation time. The default is /usr/local, so either you need root permissions, or you choose a <prefix> for which you have write permission. The files ../include/NTL/* are copied into <prefix>/include/NTL. The file ntl.a is copied to <prefix>/lib/libntl.a. The files ../doc/* are copied into <prefix>/doc/NTL.

You can also "fine tune" the installation procedure further. See the configure documentation for details.

Executing make uninstall undoes make install.

Executing make clobber essentially undoes make. Make sure you do this if you re-build NTL for a different architecture!

Executing make clean will remove object files, but not ntl.a. To rebuild after executing make clean, execute make ntl.a.

Assuming you have installed NTL as above, to compile a program foo.c that uses NTL, execute

   g++ -I<prefix>/include -L<prefix>/lib foo.c -o foo -lntl -lm
This compiles foo.c as a C++ program and creates the binary foo.

If you built NTL using GMP, execute:

   g++ -I<prefix>/include -L<prefix>/lib -L<gmp_prefix>/lib  foo.c -lntl -lgmp -lm

Of course, if <prefix> and <gmp_prefix> are the same, you do not need to duplicate the -L flags, and if either are standard directories, like /usr/local, you can leave out the corresponding -I and -L flags altogether.

This works even if you are not working in the directory in which you built NTL. If you are working in that directory, you can just execute

   make foo

[Previous] [Up] [Next]