Index: /issm/trunk-jpl/m4/issm_options.m4
===================================================================
--- /issm/trunk-jpl/m4/issm_options.m4	(revision 15658)
+++ /issm/trunk-jpl/m4/issm_options.m4	(revision 15659)
@@ -494,4 +494,35 @@
 	AC_MSG_RESULT($HAVE_ADIC2)
 	dnl }}}
+	dnl atlas{{{
+	AC_ARG_WITH([atlas-dir],
+	  AS_HELP_STRING([--with-atlas-dir=DIR],[atlas root directory]),
+	  [ATLAS_ROOT=$withval],[ATLAS_ROOT=""])
+			  
+	AC_MSG_CHECKING(for atlas and cblas libraries in $ATLAS_ROOT)
+	if test -d "$ATLAS_ROOT"; then
+
+		dnl defaults
+		HAVE_ATLAS=yes
+	
+		dnl: branch on whether we are running on windows or linux.
+		case "${host_os}" in
+			*cygwin*)
+			ATLASLIB="-L`cygpath -m $ATLAS_ROOT` -Wl,libatlas.lib  -Wl,libcblas.lib"
+			;;
+			*linux*)
+			ATLASLIB=-L"$ATLAS_ROOT/lib -lcblas -latlas -lm " 
+			;;
+			*darwin*)
+			ATLASLIB=-L"$ATLAS_ROOT/lib -lcblas -latlas -lm" 
+			;;
+		esac
+
+		AC_DEFINE([_HAVE_ATLAS_],[1],[with ATLAS in ISSM src])
+		AC_SUBST([ATLASLIB])
+	else
+		HAVE_ATLAS=no
+	fi
+	AC_MSG_RESULT($HAVE_ATLAS)
+	dnl }}}
 	dnl gsl{{{
 	AC_ARG_WITH([gsl-dir],
@@ -505,5 +536,10 @@
 		HAVE_GSL=yes
 		GSLINCL="-I$GSL_ROOT/include"
-		GSLLIB="-dy -L$GSL_ROOT/lib -lgsl -lgslcblas -lm"
+
+		if test "x$HAVE_ATLAS" = "xyes" ; then
+			GSLLIB="-dy -L$GSL_ROOT/lib -lgsl -L$ATLAS_ROOT/lib -lcblas -latlas -lm"
+		else
+			GSLLIB="-dy -L$GSL_ROOT/lib -lgsl -lgslcblas -lm"
+		fi
 
 		AC_DEFINE([_HAVE_GSL_],[1],[with gsl in ISSM src])
@@ -826,5 +862,5 @@
 	AC_MSG_RESULT($HAVE_SCALAPACK)
 	dnl }}}
-	dnl blas{{{
+	dnl blas-lapack{{{
 	AC_ARG_WITH([blas-lapack-dir],
 	  AS_HELP_STRING([--with-blas-lapack-dir=DIR],[blas-lapack root directory]),