acx_blas

This macro looks for a library that implements the BLAS linear-algebra interface (see http://www.netlib.org/blas/). On success, it sets the BLAS_LIBS output variable to hold the requisite library linkages.

To link with BLAS, you should link with:

  $BLAS_LIBS $LIBS $FLIBS

in that order. FLIBS is the output variable of the AC_F77_LIBRARY_LDFLAGS macro (called if necessary by ACX_BLAS), and is sometimes necessary in order to link with F77 libraries. Users will also need to use AC_F77_DUMMY_MAIN (see the autoconf manual), for the same reason.

Many libraries are searched for, from ATLAS to CXML to ESSL. The user may also use --with-blas=<lib> in order to use some specific BLAS library <lib>. In order to link successfully, however, be aware that you will probably need to use the same Fortran compiler (which can be set via the F77 env. var.) as was used to compile the BLAS library.

ACTION-IF-FOUND is a list of shell commands to run if a BLAS library is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it is not found. If ACTION-IF-FOUND is not specified, the default action will define HAVE_BLAS.

This macro requires autoconf 2.50 or later.

AC_DEFUN([ACX_BLAS], [
AC_PREREQ(2.50)
AC_REQUIRE([AC_F77_LIBRARY_LDFLAGS])
acx_blas_ok=no

AC_ARG_WITH(blas,
	[AC_HELP_STRING([--with-blas=<lib>], [use BLAS library <lib>])])
case $with_blas in
	yes | "") ;;
	no) acx_blas_ok=disable ;;
	-* | */* | *.a | *.so | *.so.* | *.o) BLAS_LIBS="$with_blas" ;;
	*) BLAS_LIBS="-l$with_blas" ;;
esac

# Get fortran linker names of BLAS functions to check for.
AC_F77_FUNC(sgemm)
AC_F77_FUNC(dgemm)

acx_blas_save_LIBS="$LIBS"
LIBS="$LIBS $FLIBS"

# First, check BLAS_LIBS environment variable
if test $acx_blas_ok = no; then
if test "x$BLAS_LIBS" != x; then
	save_LIBS="$LIBS"; LIBS="$BLAS_LIBS $LIBS"
	AC_MSG_CHECKING([for $sgemm in $BLAS_LIBS])
	AC_TRY_LINK_FUNC($sgemm, [acx_blas_ok=yes], [BLAS_LIBS=""])
	AC_MSG_RESULT($acx_blas_ok)
	LIBS="$save_LIBS"
fi
fi

# BLAS linked to by default?  (happens on some supercomputers)
if test $acx_blas_ok = no; then
	save_LIBS="$LIBS"; LIBS="$LIBS"
	AC_CHECK_FUNC($sgemm, [acx_blas_ok=yes])
	LIBS="$save_LIBS"
fi

# BLAS in ATLAS library? (http://math-atlas.sourceforge.net/)
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(atlas, ATL_xerbla,
		[AC_CHECK_LIB(f77blas, $sgemm,
		[AC_CHECK_LIB(cblas, cblas_dgemm,
			[acx_blas_ok=yes
			 BLAS_LIBS="-lcblas -lf77blas -latlas"],
			[], [-lf77blas -latlas])],
			[], [-latlas])])
fi

# BLAS in PhiPACK libraries? (requires generic BLAS lib, too)
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(blas, $sgemm,
		[AC_CHECK_LIB(dgemm, $dgemm,
		[AC_CHECK_LIB(sgemm, $sgemm,
			[acx_blas_ok=yes; BLAS_LIBS="-lsgemm -ldgemm -lblas"],
			[], [-lblas])],
			[], [-lblas])])
fi

# BLAS in Alpha CXML library?
if test $acx_blas_ok = no; then
fi

# BLAS in Alpha DXML library? (now called CXML, see above)
if test $acx_blas_ok = no; then
fi

# BLAS in Sun Performance library?
if test $acx_blas_ok = no; then
	if test "x$GCC" != xyes; then # only works with Sun CC
		AC_CHECK_LIB(sunmath, acosp,
			[AC_CHECK_LIB(sunperf, $sgemm,
        			[BLAS_LIBS="-xlic_lib=sunperf -lsunmath"
                                 acx_blas_ok=yes],[],[-lsunmath])])
	fi
fi

# BLAS in SCSL library?  (SGI/Cray Scientific Library)
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(scs, $sgemm, [acx_blas_ok=yes; BLAS_LIBS="-lscs"])
fi

# BLAS in SGIMATH library?
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(complib.sgimath, $sgemm,
		     [acx_blas_ok=yes; BLAS_LIBS="-lcomplib.sgimath"])
fi

# BLAS in IBM ESSL library? (requires generic BLAS lib, too)
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(blas, $sgemm,
		[AC_CHECK_LIB(essl, $sgemm,
			[acx_blas_ok=yes; BLAS_LIBS="-lessl -lblas"],
			[], [-lblas $FLIBS])])
fi

# Generic BLAS library?
if test $acx_blas_ok = no; then
	AC_CHECK_LIB(blas, $sgemm, [acx_blas_ok=yes; BLAS_LIBS="-lblas"])
fi

AC_SUBST(BLAS_LIBS)

LIBS="$acx_blas_save_LIBS"

# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
if test x"$acx_blas_ok" = xyes; then
        ifelse([$1],,AC_DEFINE(HAVE_BLAS,1,[Define if you have a BLAS library.]),[$1])
        :
else
        acx_blas_ok=no
        $2
fi
])dnl ACX_BLAS