Updated the INSTALL.swift file with the new configuration options.

INSTALL.swift

@@ -96,16 +96,20 @@ SWIFT depends on a number of third party libraries that should be available
 before you can build it.
 
 
- - HDF5: a HDF5 library (v. 1.8.x or higher) is required to read and
+ - HDF5:
+	A HDF5 library (v. 1.8.x or higher) is required to read and
         write particle data. One of the commands "h5cc" or "h5pcc"
         should be available. If "h5pcc" is located them a parallel
         HDF5 built for the version of MPI located should be
         provided. If the command is not available then it can be
         located using the "--with-hfd5" configure option. The value
         should be the full path to the "h5cc" or "h5pcc" commands.
+        SWIFT can make a very effective use of a parallel build of the
+        library when running on more than one node. This is highly
+        recommended.
 
-
- - MPI: to run on more than one node an MPI library that fully
+ - MPI:
+	To run on more than one node an MPI library that fully
         supports MPI_THREAD_MULTIPLE.  Before running configure the
         "mpirun" command should be available in the shell. If your
         command isn't called "mpirun" then define the "MPIRUN"
@@ -116,50 +120,63 @@ before you can build it.
 	much like the CC one. Use this when your MPI compiler has a
 	none-standard name.
 
- - GSL: To use cosmological time integration, a version of the GSL
+ - GSL:
+	To use cosmological time integration, a version of the GSL
 	must be available.
 
- - libtool: The build system relies on libtool as well as the other autotools.
+ - FFTW 3.x:
+	To run with periodic gravity forces, a build of the fftw 3
+	library must be available. Note that SWIFT does not make use
+	of the parallel capability of FFTW. Calculations are done by
+	single MPI nodes independently.
+
+- libtool:
+	The build system relies on libtool as well as the other autotools.
+
 
 
                            Optional Dependencies
                            =====================
 
 
- - METIS: a build of the METIS library can be optionally used to
+ - METIS:
+	a build of the METIS library can be optionally used to
         optimize the load between MPI nodes (requires an MPI
         library). This should be found in the standard installation
         directories, or pointed at using the "--with-metis"
-          configuration option.  In this case the top-level
-          installation directory of the METIS build should be
-          given. Note to use METIS you should at least supply
-          "--with-metis".
-
-
- - libNUMA: a build of the NUMA library can be used to pin the threads
-            to the physical core of the machine SWIFT is running
-            on. This is not always necessary as the OS scheduler may
-            do a good job at distributing the threads among the
-            different cores on each computing node.
-
-
- - TCMalloc: a build of the TCMalloc library (part of gperftools) can
-             be used to obtain faster allocations than the standard C
-             malloc function part of glibc. The option "-with-tcmalloc"
+        configuration option.  In this case the top-level installation
+        directory of the METIS build should be given. Note to use
+        METIS you should at least supply "--with-metis".
+
+- libNUMA:
+	a build of the NUMA library can be used to pin the threads to
+        the physical core of the machine SWIFT is running on. This is
+        not always necessary as the OS scheduler may do a good job at
+        distributing the threads among the different cores on each
+        computing node.
+
+ - tcmalloc / jemalloc / TBBmalloc:
+	a build of the tcmalloc library (part of gperftools), jemalloc
+	or TBBmalloc can be used be used to obtain faster and more
+	scalable allocations than the standard C malloc function part
+	of glibc. Using one of these is highly recommended on systems
+	with many cores per node. One of the options
+	"--with-tcmalloc", "--with-jemalloc" or "--with-tbbmalloc"
 	should be passed to the configuration script to use it.
 
+ - gperftools:
+	a build of gperftools can be used to obtain good profiling of
+        the code. The option "-with-profiler" needs to be passed to
+        the configuration script to use it.
 
- - gperftools: a build of gperftools can be used to obtain good
-               profiling of the code. The option "-with-profiler"
-               needs to be passed to the configuration script to use
-               it.
-
-
- - DOXYGEN: the doxygen library is required to create the SWIFT API
+ - DOXYGEN:
+	the doxygen library is required to create the SWIFT API
         documentation.
 
- - python:  Examples and solution script use python and rely on the
-   	    numpy library version 1.8.2 or higher.
+ - python:
+	Examples and solution script use python and rely on the numpy
+	library version 1.8.2 or higher.
+
 
 
                              SWIFT Coding style