- Added some note on SSE/SEE2 optimization.

- Supported SSE/SSE2 optimization with GCC.

git-svn-id: file:///home/svnrepos/software/liblbfgs/trunk@3 ecf4c44f-38d1-4fa4-9757-a0b4dd0349fc

README

@@ -2,7 +2,7 @@
            libLBFGS: C library of limited-memory BFGS (L-BFGS)
 
                                        Copyright (c) 1990, Jorge Nocedal 
-                                       Copyright (c) 2007, Naoaki Okazaki
+                                 Copyright (c) 2007,2008, Naoaki Okazaki 
 
 =========================================================================
 1. Introduction
@@ -22,19 +22,48 @@ http://www.chokkan.org/software/liblbfgs/
 
 
 =========================================================================
-2. How to build the sample program
+2. How to build
 =========================================================================
 [Microsoft Visual Studio 2005]
-Open the solution file "test/lbfgs.sln" and build it.
+Open the solution file "lbfgs.sln" and build it.
 
 [GCC]
-$ cd test
-$ ./build.sh
+$ ./configure
+$ make
+$ make install  # To install libLBFGS library and header.
 
 
 
 =========================================================================
-3. License
+3. Note on SSE/SSE2 optimization
+=========================================================================
+This library has SSE/SSE2 optimization routines for vector arithmetic
+operations on Intel/AMD processors. The SSE2 routine is for 64 bit double
+values whereas the SSE routine is for 32 bit float values. Since the
+default parameters for L-BFGS are tuned for double precision values, it
+may be more straightforward to use SSE2 optimization than to use SSE.
+
+To use the SSE2 optimization routine, specify --enable-sse2 option to the
+configure script.
+
+$ ./configure --enable-sse2
+
+To build libLBFGS with SSE optimization on Microsoft Visual Studio 2005,
+define USE_SSE and __SSE2__ symbols.
+
+Make sure to run libLBFGS on processors where SSE2 instrunctions are
+available.
+
+To package maintainers,
+
+Please do not enable SSE/SSE2 optimization routine. The library built
+with SSE/SSE2 optimization will crash without any notice when necessary
+SSE/SSE2 instructions are unavailable.
+
+
+
+=========================================================================
+4. License
 =========================================================================
 libLBFGS is distributed under the term of the MIT license.
 Please refer to COPYING file in the distribution.