Briefly, the shell commands should configure, build, and install this package.

How does configure work

The following more-detailed instructions are generic.

See the README' file for instructions specific to this package. Some packages provide this
INSTALL' file but do not implement all of the features documented below. The lack of an optional feature in a given package is not necessarily a bug.

The configure' shell script attempts to guess correct values for various system-dependent variables used during compilation.

It uses those values to create a Makefile' in each directory of the package. It may also create one or more .h' files containing system-dependent definitions.

Finally, it creates a shell script config.status' that you can run in the future to recreate the current configuration, and a file config.log' containing compiler output (useful mainly for debugging configure').

It can also use an optional file (typically called config.cache' and enabled with --cache-file=config.cache' or simply -C') that saves the results of its tests to speed up reconfiguring. Caching is
disabled by default to prevent problems with accidental use of stale cache files.

If you need to do unusual things to compile the package, please try to figure out how configure' could check whether to do them, and mail diffs or instructions to the address given in the README' so they can be considered for the next release. If you are using the cache, and at some point config.cache' contains results you don't want to keep, you may remove or edit it.

The file' (or') is used to create configure' by a program called autoconf'. You need' if you want to change it or regenerate configure' using a newer version of autoconf'.


The simplest way to compile this package

1. cd' to the directory containing the package's source code and type ./configure' to configure the package for your system. Running configure' might take a while. While running, it prints some messages telling which features it is checking for.

2. Type make' to compile the package.

3. Optionally, type make check' to run any self-tests that come with the package, generally using the just-built uninstalled binaries.

4. Type make install' to install the programs and any data files and documentation. When installing into a prefix owned by root, it is recommended that the package be configured and built as a regular user, and only the make install' phase executed with root privileges.

5. Optionally, type make install check' to repeat any self-tests, but this time using the binaries in their final installed location. This target does not install anything. Running this target as a regular user, particularly if the prior make install' required root privileges, verifies that the installation completed correctly.

6. You can remove the program binaries and object files from the source code directory by typing make clean'. To also remove the files that configure' created (so you can compile the package for a different kind of computer), type make distclean'. There is also a make maintainer-clean' target, but that is intended mainly for the package's developers. If you use it, you may have to get
all sorts of other programs in order to regenerate files that came with the distribution.

7. Often, you can also type make uninstall' to remove the installed files again. In practice, not all packages have tested that uninstallation works correctly, even though it is required by the GNU Coding Standards.

8. Some packages, particularly those that use Automake, provide make distcheck', which can by used by developers to test that all other targets like make install' and make uninstall' work correctly.

Compilers and Options

Some systems require unusual options for compilation or linking that the configure' script does not know about. Run ./configure --help' for details on some of the pertinent environment variables.

You can give configure' initial values for configuration parameters by setting variables in the command line or in the environment. Here is an example:


*Note Defining Variables::, for more details.

Compiling For Multiple Architectures

You can compile the package for more than one kind of computer at the
same time, by placing the object files for each architecture in their
own directory. To do this, you can use GNU
make'. cd' to the
directory where you want the object files and executables to go and run
configure' script. configure' automatically checks for the
source code in the directory that
configure' is in and in ..'. This
is known as a "VPATH" build.

With a non-GNU make', it is safer to compile the package for one architecture at a time in the source code directory. After you have installed the package for one architecture, use make distclean' before reconfiguring for another architecture.

On MacOS X 10.5 and later systems, you can create libraries and
executables that work on multiple system types--known as "fat" or
"universal" binaries--by specifying multiple
-arch' options to the
compiler but only a single -arch' option to the preprocessor. Like


By default, make install' installs the package's commands under /usr/local/bin', include files under /usr/local/include', etc. You can specify an installation prefix other than /usr/local' by giving configure' the option --prefix=PREFIX', where PREFIX must be an absolute file name.

You can specify separate installation prefixes for
architecture-specific files and architecture-independent files. If you
pass the option
--exec-prefix=PREFIX' to configure', the package uses
PREFIX as the prefix for installing programs and libraries.
Documentation and other data files still use the regular prefix.

In addition, if you use an unusual directory layout you can give
options like
--bindir=DIR' to specify different values for particular
kinds of files. Run configure --help' for a list of the directories
you can set and what kinds of files go in them. In general, the
default for these options is expressed in terms of
${prefix}', so that
specifying just --prefix' will affect all of the other directory
specifications that were not explicitly provided.

The most portable way to affect installation locations is to pass the
correct locations to
configure'; however, many packages provide one or
both of the following shortcuts of passing variable assignments to the
make install' command line to change installation locations without
having to reconfigure or recompile.

The first method involves providing an override variable for each
affected directory. For example,
make install
prefix=/alternate/directory' will choose an alternate location for all
directory configuration variables that were expressed in terms of
${prefix}'. Any directories that were specified during configure',
but not in terms of ${prefix}', must each be overridden at install
time for the entire installation to be relocated. The approach of
makefile variable overrides for each directory variable is required by
the GNU Coding Standards, and ideally causes no recompilation.
However, some platforms have known limitations with the semantics of
shared libraries that end up requiring recompilation when using this
method, particularly noticeable in packages that use GNU Libtool.

The second method involves providing the DESTDIR' variable. For
example, make install DESTDIR=/alternate/directory' will prepend
/alternate/directory' before all installation names. The approach of
DESTDIR' overrides is not required by the GNU Coding Standards, and
does not work on platforms that have drive letters. On the other hand,
it does better at avoiding recompilation issues, and works well even
when some directory options were not specified in terms of
at configure' time.

Optional Features

If the package supports it, you can cause programs to be installed
with an extra prefix or suffix on their names by giving
configure' the
option --program-prefix=PREFIX' or --program-suffix=SUFFIX'.

Some packages pay attention to --enable-FEATURE' options to
configure', where FEATURE indicates an optional part of the package.
They may also pay attention to --with-PACKAGE' options, where PACKAGE
is something like
gnu-as' or x' (for the X Window System). The
README' should mention any --enable-' and --with-' options that the
package recognizes.

For packages that use the X Window System, configure' can usually
find the X include and library files automatically, but if it doesn't,
you can use the
configure' options --x-includes=DIR' and
--x-libraries=DIR' to specify their locations.

Some packages offer the ability to configure how verbose the
execution of make' will be. For these packages, running ./configure
--enable-silent-rules' sets the default to minimal output, which can be
overridden with make V=1'; while running ./configure
--disable-silent-rules' sets the default to verbose, which can be
overridden with make V=0'.

Particular systems

On HP-UX, the default C compiler is not ANSI C compatible. If GNU
CC is not installed, it is recommended to use the following options in
order to use an ANSI C compiler:

./configure CC="cc -Ae -D_XOPEN_SOURCE=500"

and if that doesn't work, install pre-built binaries of GCC for HP-UX.

HP-UX make' updates targets which have the same time stamps as
their prerequisites, which makes it generally unusable when shipped
generated files such as configure' are involved. Use GNU make'

On OSF/1 a.k.a. Tru64, some versions of the default C compiler cannot
parse its <wchar.h>' header file. The option -nodtk' can be used as
a workaround. If GNU CC is not installed, it is therefore recommended
to try

./configure CC="cc"

and if that doesn't work, try

./configure CC="cc -nodtk"

On Solaris, don't put /usr/ucb' early in your PATH'. This
directory contains several dysfunctional programs; working variants of
these programs are available in /usr/bin'. So, if you need /usr/ucb'
in your PATH', put it _after_ /usr/bin'.

On Haiku, software installed for all users goes in /boot/common',
/usr/local'. It is recommended to use the following options:

./configure --prefix=/boot/common

Specifying the System Type

There may be some features configure' cannot figure out
automatically, but needs to determine by the type of machine the package
will run on. Usually, assuming the package is built to be run on the
_same_ architectures,
configure' can figure that out, but if it prints
a message saying it cannot guess the machine type, give it the
--build=TYPE' option. TYPE can either be a short name for the system
type, such as
sun4', or a canonical name which has the form:


where SYSTEM can have one of these forms:


See the file config.sub' for the possible values of each field. If
config.sub' isn't included in this package, then this package doesn't
need to know the machine type.

If you are _building_ compiler tools for cross-compiling, you should
use the option --target=TYPE' to select the type of system they will
produce code for.

If you want to _use_ a cross compiler, that generates code for a
platform different from the build platform, you should specify the
"host" platform (i.e., that on which the generated programs will
eventually be run) with

Sharing Defaults

If you want to set default values for configure' scripts to share,
you can create a site shell script called' that gives
default values for variables like CC', cache_file', and prefix'.
configure' looks for PREFIX/share/' if it exists, then
PREFIX/etc/' if it exists. Or, you can set the
CONFIG_SITE' environment variable to the location of the site script.
A warning: not all
configure' scripts look for a site script.

Defining Variables

Variables not defined in a site shell script can be set in the
environment passed to configure'. However, some packages may run
configure again during the build, and the customized values of these
variables may be lost. In order to avoid this problem, you should set
them in the
configure' command line, using VAR=value'. For example:

./configure CC=/usr/local2/bin/gcc

causes the specified gcc' to be used as the C compiler (unless it is
overridden in the site shell script).

Unfortunately, this technique does not work for CONFIG_SHELL' due to
an Autoconf bug. Until the bug is fixed you can use this workaround:

CONFIG_SHELL=/bin/bash /bin/bash ./configure CONFIG_SHELL=/bin/bash

configure' Invocation

configure' recognizes the following options to control how it

Print a summary of all of the options to
configure', and exit.

Print a summary of the options unique to this package's
configure', and exit. The short' variant lists options used
only in the top level, while the recursive' variant lists options
also present in any nested packages.

Print the version of Autoconf used to generate the
script, and exit.

Enable the cache: use and save the results of the tests in FILE,
config.cache'. FILE defaults to /dev/null' to
disable caching.

Alias for

Do not print messages saying which checks are being made. To
suppress all normal output, redirect it to
/dev/null' (any error
messages will still be shown).

Look for the package's source code in directory DIR. Usually
configure' can determine that directory automatically.

Use DIR as the installation prefix. *note Installation Names::
for more details, including other options available for fine-tuning
the installation locations.

Run the configure checks, but stop before creating any output

configure' also accepts some other, not widely useful, options. Run
`configure --help' for more details.



FFTW is a free collection of fast C routines for computing the
Discrete Fourier Transform in one or more dimensions. It includes
complex, real, symmetric, and parallel transforms, and can handle
arbitrary array sizes efficiently. FFTW is typically faster than
other publically-available FFT implementations, and is even
competitive with vendor-tuned libraries. (See our web page for
extensive benchmarks.) To achieve this performance, FFTW uses novel
code-generation and runtime self-optimization techniques (along with
many other tricks).

The doc/ directory contains the manual in texinfo, PDF, info, and HTML
formats. Frequently asked questions and answers can be found in the
doc/FAQ/ directory in ASCII and HTML.

For a quick introduction to calling FFTW, see the "Tutorial" section
of the manual.

Installation instructions are provided in the manual (don't worry, it
is straightforward).


FFTW was written by Matteo Frigo and Steven G. Johnson. You can
contact them at The latest version of FFTW,
benchmarks, links, and other information can be found at the FFTW home
page ( You can also sign up to the fftw-announce
mailing list to receive (infrequent) updates and information about new
releases; to do so, go to:


:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen: